Influence of Nodal signalling on pluripotency factor expression, tumour cell proliferation and cisplatin-sensitivity in testicular germ cell tumours.

BACKGROUND: Testicular germ cell tumours (TGCTs) are characterised by an overall high cisplatin-sensitivity which has been linked to their continued expression of pluripotency factors. Recently, the Nodal signalling pathway has been implicated in the regulation of pluripotency factor expression in fetal germ cells, and the pathway could therefore also be involved in regulating expression of pluripotency factors in malignant germ cells, and hence cisplatin-sensitivity in TGCTs. METHODS: We used in vitro culture of the TGCT-derived cell line NTera2, ex vivo tissue culture of primary TGCT specimens and xenografting of NTera2 cells into nude mice in order to investigate the consequences of manipulating Nodal and Activin signalling on pluripotency factor expression, apoptosis, proliferation and cisplatin-sensitivity. RESULTS: The Nodal signalling factors were markedly expressed concomitantly with the pluripotency factor OCT4 in GCNIS cells, seminomas and embryonal carcinomas. Despite this, inhibition of Nodal and Activin signalling either alone or simultaneously did not affect proliferation or apoptosis in malignant germ cells in vitro or ex vivo. Interestingly, inhibition of Nodal signalling in vitro reduced the expression of pluripotency factors and Nodal pathway genes, while stimulation of the pathway increased their expression. However, cisplatin-sensitivity was not affected following pharmacological inhibition of Nodal/Activin signalling or siRNA-mediated knockdown of the obligate co-receptor CRIPTO in NTera2 cells in vitro or in a xenograft model. CONCLUSION: Our findings suggest that the Nodal signalling pathway may be involved in regulating pluripotency factor expression in malignant germ cells, but manipulation of the pathway does not appear to affect cisplatin-sensitivity or tumour cell proliferation.

Dysregulation of FGFR signalling by a selective inhibitor reduces germ cell survival in human fetal gonads of both sexes and alters the somatic niche in fetal testes.

STUDY QUESTION: Does experimental manipulation of fibroblast growth factor 9 (FGF9)-signalling in human fetal gonads alter sex-specific gonadal differentiation? SUMMARY ANSWER: Inhibition of FGFR signalling following SU5402 treatment impaired germ cell survival in both sexes and severely altered the developing somatic niche in testes, while stimulation of FGF9 signalling promoted Sertoli cell proliferation in testes and inhibited meiotic entry of germ cells in ovaries. WHAT IS KNOWN ALREADY: Sex-specific differentiation of bipotential gonads involves a complex signalling cascade that includes a combination of factors promoting either testicular or ovarian differentiation and inhibition of the opposing pathway. In mice, FGF9/FGFR2 signalling has been shown to promote testicular differentiation and antagonize the female developmental pathway through inhibition of WNT4. STUDY DESIGN, SIZE, DURATION: FGF signalling was manipulated in human fetal gonads in an established ex vivo culture model by treatments with recombinant FGF9 (25 ng/ml) and the tyrosine kinase inhibitor SU5402 (10 µM) that was used to inhibit FGFR signalling. Human fetal testis and ovary tissues were cultured for 14 days and effects on gonadal development and expression of cell lineage markers were determined. PARTICIPANTS/MATERIALS, SETTING, METHODS: Gonadal tissues from 44 male and 33 female embryos/fetuses from first trimester were used for ex vivo culture experiments. Tissues were analyzed by evaluation of histology and immunohistochemical analysis of markers for germ cells, somatic cells, proliferation and apoptosis. Culture media were collected throughout the experimental period and production of steroid hormone metabolites was analyzed in media from fetal testis cultures by liquid chromatography-tandem mass spectrometry (LC-MS/MS). MAIN RESULTS AND THE ROLE OF CHANCE: Treatment with SU5402 resulted in near complete loss of gonocytes (224 vs. 14 OCT4+ cells per mm2, P < 0.05) and oogonia (1456 vs. 28 OCT4+ cells per mm2, P < 0.001) in human fetal testes and ovaries, respectively. This was a result of both increased apoptosis and reduced proliferation in the germ cells. Addition of exogenous FGF9 to the culture media resulted in a reduced number of germ cells entering meiosis in fetal ovaries (102 vs. 60 γH2AX+ germ cells per mm2, P < 0.05), while in fetal testes FGF9 stimulation resulted in an increased number of Sertoli cells (2503 vs. 3872 SOX9+ cells per mm2, P < 0.05). In fetal testes, inhibition of FGFR signalling by SU5402 treatment altered seminiferous cord morphology and reduced the AMH expression as well as the number of SOX9-positive Sertoli cells (2503 vs. 1561 SOX9+ cells per mm2, P < 0.05). In interstitial cells, reduced expression of COUP-TFII and increased expression of CYP11A1 and CYP17A1 in fetal Leydig cells was observed, although there were no subsequent changes in steroidogenesis. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Ex vivo culture may not replicate all aspects of fetal gonadal development and function in vivo. Although the effects of FGF9 were studied in ex vivo culture experiments, there is no direct evidence that FGF9 acts in vivo during human fetal gonadogenesis. The FGFR inhibitor (SU5402) used in this study is not specific to FGFR2 but inhibits all FGF receptors and off-target effects on unrelated tyrosine kinases should be considered. WIDER IMPLICATIONS OF THE FINDINGS: The findings of this study suggest that dysregulation of FGFR-mediated signalling may affect both testicular and ovarian development, in particular impacting the fetal germ cell populations in both sexes. STUDY FUNDING/COMPETING INTEREST(S): This work was supported in part by an ESPE Research Fellowship, sponsored by Novo Nordisk A/S to A.JØ. Additional funding was obtained from the Erichsen Family Fund (A.JØ.), the Aase and Ejnar Danielsens Fund (A.JØ.), the Danish Government's support for the EDMaRC programme (A.JU.) and a Wellcome Trust Intermediate Clinical Fellowship (R.T.M., Grant no. 098522). The Medical Research Council (MRC) Centre for Reproductive Health (R.T.M.) is supported by an MRC Centre Grant (MR/N022556/1). The authors have no conflict of interest to disclose.

Decrease in semen quality and Leydig cell function in infertile men: a longitudinal study.

STUDY QUESTION: Are infertile men with reduced semen quality at risk of a further decrease in testicular function? SUMMARY ANSWER: Infertile men with severely reduced semen quality risk further deterioration of semen quality 15 years after treatment for infertility, and a lower baseline sperm concentration was associated with a more pronounced increase in LH and decrease in testosterone/LH ratio at follow-up. WHAT IS KNOWN ALREADY: Male factors account for up to 50% of human infertility. The most common finding is spermatogenic failure (SgF) yet the life course of semen quality and testosterone production in such men has not been described. STUDY DESIGN, SIZE, DURATION: A follow-up study of men with SgF was performed 15 years after the initial infertility assessment between January 1995 and December 2000. PARTICIPANTS/MATERIALS, SETTING, METHODS: Hospital records were used to identify potential participants in the study. A total of 137 men with primary male infertility due to SgF and 70 controls with good semen quality from couples with female factor infertility who attended a tertiary referral centre were included: the participation rate was 31% and 26%, respectively. The men provided semen samples and underwent a physical examination. Blood samples were taken to measure levels of reproductive hormones (FSH, LH, testosterone, sex hormone-binding globulin, estradiol and inhibin B). Current results were compared with results from the initial assessments. MAIN RESULTS AND THE ROLE OF CHANCE: At the time of follow up the SgF men had significantly lower Leydig cell capacity than the control group as well as much lower semen quality. For the SgF men, between baseline sampling and follow up, the median sperm concentration decreased from 1.9 to 0.6 mill/ml and total sperm count from 7.7 to 2.0 million (P = 0.019 and 0.012, respectively), and 10% developed azoospermia. Calculated free testosterone (cFT), but not total testosterone (tT) decreased in the SgF group by ~0.6% (95% CI 0.1-1.2%) per year. In the SgF group, LH increased by 1.6% (CI 0.9-2.3%) annually, and consequently tT/LH and cFT/LH ratios had decreased by 1.3% (CI 0.5-2.1) and 2.1% (CI 1.2-3.0%), respectively. The increase in LH and the decreases in tT/LH and cFT/LH ratios were more pronounced in men with lower baseline sperm concentrations. LIMITATIONS, REASONS FOR CAUTION: We consider the case group as representative of infertile men not in need of testosterone treatment at baseline investigation, but do not have information on those that chose not to participate in the follow-up study. There were alterations in some hormone analysis methods during the follow-up period that may introduce uncertainty in interpretation of long-term changes in hormone levels despite rigorous quality control. The validity of the control group suffers from a lack of hormone values at baseline. Also, at follow-up, for practical reasons only one semen sample could be obtained, which makes the effect estimate more uncertain and there is a risk of non-differential misclassification. WIDER IMPLICATIONS OF THE FINDINGS: Without being able to predict individual outcomes, it is prudent to consider sperm cryopreservation or advise not to postpone fertility treatment when men present with infertility due to impaired semen quality. Whether partly compensated Leydig cell insufficiency in men with SgF will eventually develop into overt testosterone deficiency cannot be determined from our study. STUDY FUNDING/COMPETING INTEREST(s): Aase and Einar Danielsen (Grant no. 10-001053), Nordic Research Committee (Grant no. 5109), The Kirsten and Freddie Johansen Fund, and Rigshospitalet's Research Fund (grant no. R24-A812). There are no competing interests.

Factor V Leiden is associated with increased sperm count.

STUDY QUESTION: Is the thrombophilia mutation factor V Leiden (FVL) associated with an increased total sperm count? SUMMARY ANSWER: Carriers of FVL have a higher total sperm count than non-FVL-carriers, which could not be explained by genetic linkage or by observations in a FVL-mouse model. WHAT IS KNOWN ALREADY: FVL has a high prevalence in Caucasians despite detrimental health effects. Carriers have been shown to have higher fecundity, which might partly explain this evolutionary paradox. STUDY DESIGN, SIZE, DURATION: We determined FVL status in two cohorts (Dutch, n = 627; Danish, n = 854) of consecutively included men without known causes for spermatogenic failure, and performed an individual patient data meta-analysis of these two cohorts together with one previously published (Dutch, n = 908) cohort. We explored possible biological underpinnings for the relation between sperm count and FVL, by use of a FVL-mouse model and investigations of genetic linkage. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were male partners of subfertile couples (two Dutch cohorts) and young men from the general population (Danish cohort): FVL carrier rate was 4.0%, 4.6% and 7.3%, respectively. There were differences in smoking, abstinence time and age between the cohorts. We corrected for these in the primary analysis, which consisted of a mixed linear effects model, also incorporating unobjectified population differences. In public haplotype data from subjects of European descent, we explored linkage disequilibrium of FVL with all known single nucleotide polymorphisms in a 1.5 MB region around the F5 gene with an R2 cutoff of 0.8. We sequenced exons of four candidate genes hypothesized to be linked to FVL in a subgroup of FVL carriers with extreme sperm count values. The animal studies consisted of never mated 15-18-week-old C57BL/J6 mice heterozygous and homozygous for FVL and wild-type mice. We compared spermatogenesis parameters (normalized internal genitalia weights, epididymis sperm content and sperm motility) between FVL and wild-type mice. MAIN RESULTS AND THE ROLE OF CHANCE: Human FVL carriers have a higher total sperm count than non-carriers, with an adjusted mean difference of 31 × 106 (95%CI 0.2-61.7; P = 0.048). Mice with the FVL mutation do not have increased spermatogenesis as compared to wildtype mice. None of the studied polymorphisms was in linkage disequilibrium, either in the public databases or in a subgroup of FVL carriers with extremely high sperm counts. LIMITATIONS, REASONS FOR CAUTION: The difference in total sperm count would benefit from confirmation in other cohorts. The finding of higher count in carriers was consistent however, with no heterogeneity between the cohorts. The lack of effect of murine FVL might suggest there is no direct causality. The exploratory efforts on genetic linkage do not rule out that the association is a reflection of FVL co-inheritance with a non-studied causative polymorphism. WIDER IMPLICATIONS OF THE FINDINGS: A high sperm count in FVL-carrying males contributes to understanding the high prevalence of this otherwise disadvantageous mutation. The findings might provide directions for future research on male fertility. STUDY FUNDING/COMPETING INTEREST(S): No conflicts of interest. Research was conducted with funding from the Netherlands Organisation for Scientific Research (NWO, VIDI innovative research grant 016.126.364 awarded to S. Middeldorp). The Danish cohort was supported by the Innovation Fund Denmark (InnovationsFonden, grant no. 14-2013-4), The Danish Ministry of Health and the Danish Environmental Protection Agency. TRIAL REGISTRATION NUMBER: Not applicable.

Screening for carcinoma in situ in the contralateral testicle in patients with testicular cancer: a population-based study.

BACKGROUND: Screening programmes for contralateral carcinoma in situ (CIS) testis in patients with unilateral germ-cell cancer (GCC) have never been evaluated. We investigated the effect of screening for contralateral CIS in a large nation-wide, population-based study. PATIENTS AND METHODS: A contralateral single-site biopsy was offered to 4130 patients in whom GCC had been diagnosed in 1984-2007 (screened cohort); 462 patients in whom GCC was diagnosed in 1984-1988 comprised the unscreened cohort. Cases with CIS were offered radiotherapy. Initially CIS-negative biopsies in patients with metachronous GCC were revised according to today's standards. Risk for metachronous GCC was estimated using cumulative incidence and the Cox proportional hazards model. RESULTS: In the screened cohort, contralateral CIS was found in 181 (4.4%) patients. The cumulative incidence of metachronous GCC after 20 years was 1.9% in the screened cohort and 3.1% in the unscreened cohort (P = 0.097), hazard ratio (HR) for the unscreened cohort: 1.59 (P = 0.144). Expert revision with contemporary methodology of CIS-negative biopsy samples from patients with metachronous cancer revealed CIS in 17 out of 45 (38%) cases. Decreased risks for metachronous GCC were related to older age at diagnosis (HR 0.52 per 10 years, P < 0.001) and chemotherapy (HR 0.35, P = 0.002). Limitations include the small number of patients in the unscreened cohort and the retrospective study design. CONCLUSIONS: Our evaluation of a national population-based screening programme for contralateral CIS in patients with testicular cancer showed no significant difference in the risk for metachronous GCC between a screened and an unscreened cohort. Single-site biopsy including modern immunohistochemistry does not identify all cases of CIS.

Ex vivo culture of human fetal gonads: manipulation of meiosis signalling by retinoic acid treatment disrupts testis development.

STUDY QUESTION: What are the effects of experimentally manipulating meiosis signalling by addition of retinoic acid (RA) in cultured human fetal gonads? SUMMARY ANSWER: RA-treatment accelerated meiotic entry in cultured fetal ovary samples, while addition of RA resulted in a dysgenetic gonadal phenotype in fetal testis cultures. WHAT IS KNOWN ALREADY: One of the first manifestations of sex differentiation is the initiation of meiosis in fetal ovaries. In contrast, meiotic entry is actively prevented in the fetal testis at this developmental time-point. It has previously been shown that RA-treatment mediates initiation of meiosis in human fetal ovary ex vivo. STUDY DESIGN, SIZE, DURATION: This was a controlled ex vivo study of human fetal gonads treated with RA in 'hanging-drop' tissue cultures. The applied experimental set-up preserves germ cell-somatic niche interactions and the investigated outcomes included tissue integrity and morphology, cell proliferation and survival and the expression of markers of meiosis and sex differentiation. PARTICIPANTS/MATERIALS, SETTING, METHODS: Tissue from 24 first trimester human fetuses was included in this study, all from elective terminations at gestational week (GW) 7-12. Gonads were cultured for 2 weeks with and without addition of 1 µM RA. Samples were subsequently formalin-fixed and investigated by immunohistochemistry and cell counting. Proteins investigated and quantified included; octamer-binding transcription factor 4 (OCT4), transcription factor AP-2 gamma (AP2γ) (embryonic germ cell markers), SRY (sex determining region Y)-box 9 (SOX9), anti-Müllerian hormone (AMH) (immature Sertoli cell markers), COUP transcription factor 2 (COUP-TFII) (marker of interstitial cells), forkhead box L2 (FOXL2) (granulosa cell marker), H2A histone family, member X (γH2AX) (meiosis marker), doublesex and mab-3 related transcription factor 1 (DMRT1) (meiosis regulator), cleaved poly ADP ribose polymerase (PARP), cleaved Caspase 3 (apoptosis markers) and Ki-67 antigen (Ki-67) (proliferation marker). Also, proliferation was determined using a 5'-bromo-2'-deoxyuridine (BrdU) incorporation assay. MAIN RESULTS AND THE ROLE OF CHANCE: A novel ex vivo 'hanging-drop' culture model for human fetal gonads was successfully established. Continued proliferation of cells without signs of increased apoptosis was observed after 2 weeks of culture. In cultured fetal ovaries treated with RA, an increased number of meiotic germ cells (P < 0.05) and DMRT1-positive oogonia initiating meiosis (P < 0.05) was observed, which is in agreement with a previous study. In fetal testes, RA-treatment resulted in a decreased number of gonocytes (P < 0.05), a reduced percentage of proliferating gonocytes (P < 0.05), altered expression pattern of the somatic cell markers AMH and COUP-TFII, as well as disrupted seminiferous cord structure and testis morphology. LIMITATIONS, REASONS FOR CAUTION: The number of samples included in this study was relatively small due to the limited availability of human fetal tissue. WIDER IMPLICATIONS OF THE FINDINGS: The hanging-drop culture, similarly to other organ culture approaches, allows studies of germ cell-somatic niche interactions and determination of effects after manipulating specific signalling pathways. Our novel finding of disrupted fetal testis development after treatment with RA indicates that abnormal meiosis regulation can potentially cause gonadal dysgenesis. Further studies will elucidate the exact mechanisms and timing of observed effects. STUDY FUNDING/COMPETING INTERESTS: This work was supported in part by an ESPE Research Fellowship, sponsored by Novo Nordisk A/S to A.Jø. Additional funding for this project was obtained from The Research Council of the Capital Region of Denmark (E.R.-D.M.), The Research Fund at Rigshospitalet (A.Ju. and J.E.N.), Familien Erichssens Fund (A.Jø.), Dagmar Marshalls Fund (A.Jø.) and Aase & Ejnar Danielsens Fund (A.Jø.). The authors have no conflicts of interest.

Evidence that active demethylation mechanisms maintain the genome of carcinoma in situ cells hypomethylated in the adult testis.

BACKGROUND: Developmental arrest of fetal germ cells may lead to neoplastic transformation and formation of germ cell tumours via carcinoma in situ (CIS) cells. Normal fetal germ cell development requires complete erasure and re-establishment of DNA methylation. In contrast to normal spermatogonia, the genome of CIS cells remains unmethylated in the adult testis. We here investigated the possible active and passive pathways that can sustain the CIS genome hypomethylated in the adult testis. METHODS: The levels of 5-methyl-cytosine (5mC) and 5-hydroxy-methyl-cytosine (5hmC) in DNA from micro-dissected CIS cells were assessed by quantitative measurements. The expression of TET1, TET2, APOBEC1, MBD4, APEX1, PARP1, DNMT1, DNMT3A, DNMT3B and DNMT3L in adult testis specimens with CIS and in human fetal testis was investigated by immunohistochemistry and immunofluorescence. RESULTS: DNA from micro-dissected CIS cells contained very low levels of 5hmC produced by ten eleven translocation (TET) enzymes. CIS cells and fetal germ cells expressed the suggested initiator of active demethylation, APOBEC1, and the base excision repair proteins MBD4, APEX1 and PARP1, whereas TETs - the alternative initiators were absent. Both maintenance and de novo methyltransferases were detected in CIS cells. CONCLUSION: The data are consistent with the presence of an active DNA de-methylation pathway in CIS cells. The hypomethylated genome of CIS cells may contribute to phenotypic plasticity and invasive capabilities of this testicular cancer precursor.

Hanging drop cultures of human testis and testis cancer samples: a model used to investigate activin treatment effects in a preserved niche.

BACKGROUND: Testicular germ cell tumours of young adults, seminoma or non-seminomas, are preceded by a pre-invasive precursor, carcinoma in situ (CIS), understood to arise through differentiation arrest of embryonic germ cells. Knowledge about the malignant transformation of germ cells is currently limited by the lack of experimental models. The aim of this study was to establish an experimental tissue culture model to maintain normal and malignant germ cells within their niche and allow investigation of treatment effects. METHODS: Human testis and testis cancer specimens from orchidectomies were cultured in 'hanging drops' and effects of activin A and follistatin treatment were investigated in seminoma cultures. RESULTS: Testis fragments with normal spermatogenesis or CIS cells were cultured for 14 days with sustained proliferation of germ cells and CIS cells and without increased apoptosis. Seminoma cultures survived 7 days, with proliferating cells detectable during the first 5 days. Activin A treatment significantly reduced KIT transcript and protein levels in seminoma cultures, thereby demonstrating a specific treatment response. CONCLUSIONS: Hanging drop cultures of human testis and testis cancer samples can be employed to delineate mechanisms governing growth of normal, CIS and tumorigenic germ cells retained within their niche.

Validation of endogenous normalizing genes for expression analyses in adult human testis and germ cell neoplasms.

The measurement of gene expression levels in cells and tissues typically depends on a suitable point of reference for inferring biological relevance. For quantitative (or real-time) RT-PCR assays, the method of choice is often to normalize gene expression data to an endogenous gene that is stably expressed across the samples analysed: a so-called normalizing or housekeeping gene. Although this is a valid strategy, the identification of stable normalizing genes has proved challenging and a gene showing stable expression across all cells or tissues is unlikely to exist. Therefore, it is necessary to define suitable normalizing genes for specific cells and tissues. Here, we report on the performance of a panel of nine commonly employed normalizing genes in adult human testis and testicular pathologies. Our analyses revealed significant variability in transcript abundance for commonly used normalizers, highlighting the importance of selecting appropriate normalizing genes as comparative measurements can yield variable results when different normalizing genes are employed. Based on our results, we recommend using RPS20, RPS29 or SRSF4 when analysing relative gene expression levels in human testis and associated testicular pathologies. OCT4 and SALL4 can be used with caution as second-tier normalizers when determining changes in gene expression in germ cells and germ cell tumour components, but the relative transcript abundance appears variable between different germ cell tumour types. We further recommend that such studies should be accompanied by additional assessment of histology and cellularity of each sample.

Expression patterns of DLK1 and INSL3 identify stages of Leydig cell differentiation during normal development and in testicular pathologies, including testicular cancer and Klinefelter syndrome.

STUDY QUESTION: What is the differentiation stage of human testicular interstitial cells, in particular Leydig cells (LC), within micronodules found in patients with infertility, testicular cancer and Klinefelter syndrome? SUMMARY ANSWER: The Leydig- and peritubular-cell populations in testes with dysgenesis contain an increased proportion of undifferentiated cells when compared with control samples, as demonstrated by increased delta-like homolog 1 (DLK1) and decreased insulin-like peptide 3 (INSL3) expression. WHAT IS KNOWN ALREADY: Normal LC function is essential for male development and reproduction. Signs of LC failure, including LC micronodules, are often observed in patients with reproductive disorders. STUDY DESIGN, SIZE, PARTICIPANTS: In this retrospective study, a panel of markers and factors linked to the differentiation of LCs was investigated in 33 fetal and prepubertal human specimens and in 58 adult testis samples from patients with testicular germ cell tumours, including precursor carcinoma in situ (CIS), infertility or Klinefelter syndrome. PARTICIPANTS/MATERIALS, SETTING, METHODS: The expression patterns of DLK1, INSL3, chicken ovalbumin upstream promoter transcription factor 2 (COUP-TFII), cytochrome P450, family 11, subfamily A, polypeptide 1 (CYP11A1) and smooth muscle actin (SMA) were investigated by immunohistochemistry and quantitative RT-PCR. The percentage of positive LCs was estimated and correlated to total LC numbers and serum levels of reproductive hormones. MAIN RESULTS AND THE ROLE OF CHANCE: DLK1, INSL3 and COUP-TFII expression changed during normal development and was linked to different stages of LC differentiation: DLK1 was expressed in all fetal LCs, but only in spindle-shaped progenitor cells and in a small subset of polygonal LCs in the normal adult testis; INSL3 was expressed in a subset of fetal LCs, but in the majority of adult LCs; and COUP-TFII was expressed in peritubular and mesenchymal stroma cells at all ages, in fetal LCs early in gestation and in a subset of adult LCs. CYP11A1 was expressed in the majority of LCs regardless of age and pathology and was the best general LC marker examined here. SMA was weakly expressed in peritubular cells in the fetal and infantile testis, but strongly expressed in the adult testis. In pathological testes, the numbers of DLK1-positive interstitial cells were increased. The proportion of DLK1-positive LCs correlated with total LC numbers (R = 0.53; P < 0.001) and was higher in testis with enlargement of the peritubular layers (P < 0.01), which was also highly associated with DLK1 expression in the peritubular compartment (P < 0.001). INSL3 expression was absent in some, but not all LC micronodules, and in the majority of LCs, it was mutually exclusive of DLK1. LIMITATIONS, REASONS FOR CAUTION: The number of samples was relatively small and no true normal adult controls were available. True stereology was not used for LC counting, instead LCs were counted in three fields of 0.5 µm(2) surface for each sample. WIDER IMPLICATIONS OF THE FINDINGS: The population of LCs, especially those clustered in large nodules, are heterogeneous and comprise cells at different stages of differentiation. The study demonstrated that the differentiation and function of LCs, and possibly also peritubular cells, are impaired in adult men with testicular pathologies including testis cancer and Klinefelter syndrome. STUDY FUNDING/COMPETING INTERESTS: This work was funded by Rigshospitalet's research funds, the Danish Cancer Society and Kirsten and Freddy Johansen's foundation. The authors have no conflicts of interest.

Maintaining success, reducing treatment burden, focusing on survivorship: highlights from the third European consensus conference on diagnosis and treatment of germ-cell cancer.

In November 2011, the Third European Consensus Conference on Diagnosis and Treatment of Germ-Cell Cancer (GCC) was held in Berlin, Germany. This third conference followed similar meetings in 2003 (Essen, Germany) and 2006 (Amsterdam, The Netherlands) [Schmoll H-J, Souchon R, Krege S et al. European consensus on diagnosis and treatment of germ-cell cancer: a report of the European Germ-Cell Cancer Consensus Group (EGCCCG). Ann Oncol 2004; 15: 1377-1399; Krege S, Beyer J, Souchon R et al. European consensus conference on diagnosis and treatment of germ-cell cancer: a report of the second meeting of the European Germ-Cell Cancer Consensus group (EGCCCG): part I. Eur Urol 2008; 53: 478-496; Krege S, Beyer J, Souchon R et al. European consensus conference on diagnosis and treatment of germ-cell cancer: a report of the second meeting of the European Germ-Cell Cancer Consensus group (EGCCCG): part II. Eur Urol 2008; 53: 497-513]. A panel of 56 of 60 invited GCC experts from all across Europe discussed all aspects on diagnosis and treatment of GCC, with a particular focus on acute and late toxic effects as well as on survivorship issues. The panel consisted of oncologists, urologic surgeons, radiooncologists, pathologists and basic scientists, who are all actively involved in care of GCC patients. Panelists were chosen based on the publication activity in recent years. Before the meeting, panelists were asked to review the literature published since 2006 in 20 major areas concerning all aspects of diagnosis, treatment and follow-up of GCC patients, and to prepare an updated version of the previous recommendations to be discussed at the conference. In addition, ∼50 E-vote questions were drafted and presented at the conference to address the most controversial areas for a poll of expert opinions. Here, we present the main recommendations and controversies of this meeting. The votes of the panelists are added as online supplements.

AZFa protein DDX3Y is differentially expressed in human male germ cells during development and in testicular tumours: new evidence for phenotypic plasticity of germ cells.

BACKGROUND: DDX3Y (DBY), located within AZoospermia Factor a (AZFa) region of the human Y chromosome (Yq11), encodes a conserved DEAD-box RNA helicase expressed only in germ cells and with a putative function at G1-S phase of the cell cycle. Deletion of AZFa results most often in germ cell aplasia, i.e. Sertoli-cell-only syndrome. To investigate the function of DDX3Y during human spermatogenesis, we examined its expression during development and maturation of the testis and in several types of testicular germ cell tumours (TGCTs), including the pre-invasive carcinoma in situ (CIS) precursor cells which are believed to originate from fetal gonocytes. METHODS: DDX3Y protein expression was analysed during development in different tissues by western blotting. The localization of DDX3Y in normal fetal and prepubertal testis tissue of different ages as well as in a series of distinct TGCT tissue samples (CIS, classical seminoma, spermatocytic seminoma, teratoma and embryonal carcinoma) was performed by immunohistochemistry. RESULTS: Germ cell-specific expression of DDX3Y protein was revealed in fetal prospermatogonia but not in gonocytes and not before the 17th gestational week. After birth, DDX3Y was expressed at first only in the nuclei of Ap spermatogonia, then also in the cytoplasm similarly to that seen after puberty. In CIS cells, DDX3Y was highly expressed and located predominantly in the nuclei. In invasive TGCT, significant DDX3Y expression was found in seminomas of the classical and spermatocytic type, but not in somatically differentiated non-seminomas, consistent with its germ-cell specific function. CONCLUSIONS: The fetal germ cell DDX3Y expression suggests a role in early spermatogonial proliferation and implies that, in men with AZFa deletion, germ cell depletion may begin prenatally. The strong expression of DDX3Y in CIS cells, but not in gonocytes, indicates phenotypic plasticity of CIS cells and suggests partial maturation to spermatogonia, likely due to their postpubertal microenvironment.

Expression of the vitamin D metabolizing enzyme CYP24A1 at the annulus of human spermatozoa may serve as a novel marker of semen quality.

Vitamin D (VD) is important for male reproduction in mammals and the VD receptor (VDR) and VD-metabolizing enzymes are expressed in human spermatozoa. The VD-inactivating enzyme CYP24A1 titrates the cellular responsiveness to VD, is transcriptionally regulated by VD, and has a distinct expression at the sperm annulus. Here, we investigated if CYP24A1 expression serves as a marker for VD metabolism in spermatozoa, and whether CYP24A1 expression was associated with semen quality. We included 130 men (53 healthy young volunteers and 77 subfertile men) for semen analysis and immunocytochemical (ICC) detection of CYP24A1. Another 40 men (22 young, 18 subfertile) were tested for in vitro effects of 1,25(OH)(2)D(3) on intracellular calcium concentration ([Ca(2+)](i)) and sperm motility. Double ICC staining showed that CYP24A1 and VDR were either concomitantly expressed or absent in 80% of the spermatozoa from young men. The median number of CYP24A1-expressing spermatozoa was 1% in subfertile men and thus significantly (p < 0.0005) lower than 25% in spermatozoa from young men. Moreover, CYP24A1 expression correlated positively with total sperm count, -concentration, -motility and -morphology (all p < 0.004), and the percentage of CYP24A1-positive spermatozoa increased (15 vs. 41%, p < 0.0005) after percoll-gradient-centrifugation. We noticed that the presence of >3% CYP24A1-positive spermatozoa distinguished young men from subfertile men with a sensitivity of 66.0%, a specificity of 77.9% and a positive predictive value of 98.3%. Functional studies revealed that 1,25(OH)(2)D(3) increased [Ca(2+)](i) and sperm motility in young healthy men, while 1,25(OH)(2)D(3) was unable to increase motility in subfertile patients. In conclusion, we suggest that CYP24A1 expression at the annulus may serve as a novel marker of semen quality and an objective proxy for sperm function.

A novel double staining strategy for improved detection of testicular carcinoma in situ cells in human semen samples.

Prompted by the recently reported expression of POU5F1 (OCT3/4) in epididymis, a panel of markers for carcinoma in situ (CIS) testis and testicular germ cell tumours (TGCT), including AP-2γ(TFAP2C), NANOG, OCT3/4, KIT, placental-like alkaline phosphatase (PLAP), M2A/PDPN and MAGE-A4 were examined by immunohistochemistry or in situ hybridisation in urogenital epithelia, which may interfere with detection of CIS cells in semen. In addition to OCT3/4, the expression of AP-2γ and NANOG or their variants was detected in urogenital epithelia, while other CIS markers, including PLAP/alkaline phosphatase were absent. A combination of immunocytological staining for AP-2γ or OCT3/4 and rapid cytochemical alkaline phosphatase reaction was subsequently developed. This approach was tested in 22 patients with TGCT. In 14 patients (63.6%), double stained cells were found and thus the method was proven suitable for the detection of CIS cells in semen. In conclusion, transcription factors related to pluripotency and undifferentiated state of cells, which most likely have several variants or modifications, are unexpectedly detected using currently available antibodies in urogenital epithelial cells which may be shed into semen. Combining the immunohistochemical nuclear markers with a rapid cytochemical alkaline phosphatase reaction for detection of CIS cells in ejaculates may provide a more reliable diagnostic method.

Heterochromatin marks HP1γ, HP1α and H3K9me3, and DNA damage response activation in human testis development and germ cell tumours.

Heterochromatinization has been implicated in fundamental biological and pathological processes including differentiation, senescence, ageing and tumourigenesis; however, little is known about its regulation and roles in human cells and tissues in vivo. Here, we show distinct cell-type- and cancer-stage-associated patterns of key heterochromatin marks: histone H3 trimethylated at lysine 9 (H3K9me3) and heterochromatic adaptor proteins HP1α and HP1γ, compared with the γH2AX marker of endogenously activated DNA damage response (DDR) and proliferation markers in normal human foetal (n=4) and adult (n=29) testes, pre-invasive carcinoma in situ (CIS; n=26) lesions and a series of overt germ cell tumours, including seminomas (n=26), embryonal carcinomas (n=18) and teratomas (n=11). Among striking findings were high levels of HP1γ in foetal gonocytes, CIS and seminomas; enhanced multimarker heterochromatinization without DDR activation in CIS; and enhanced HP1α in teratoma structures with epithelial and neuronal differentiation. Differential expression of the three heterochromatin markers suggests their partly non-overlapping roles, and separation of heterochromatinization from DDR activation highlights distinct responses of germ cells vs. somatic tissues in early tumourigenesis. Conceptually interesting findings were that subsets of human cells in vivo proliferate despite enhanced heterochromatinization, and that cells can strongly express even multiple heterochromatin features in the absence of functional retinoblastoma protein and without DDR activation. Overall, these results provide novel insights into cell-related and tumour-related diversity of heterochromatin in human tissues in vivo, relevant for andrology and intrinsic anti-tumour defence roles attributed to activated DDR and cellular senescence.

Testicular germ cell tumours in dogs are predominantly of spermatocytic seminoma type and are frequently associated with somatic cell tumours.

Unlike seminomas in humans, seminomas in animals are not typically sub-classified as classical or spermatocytic types. To compare testicular germ cell tumours (TGCT) in dogs with those of men, archived tissues from 347 cases of canine testicular tumours were morphologically evaluated and characterized using human classification criteria. Histopathological and immunohistological analysis of PLAP, KIT, DAZ and DMRT1 expression revealed that canine seminomas closely resemble human spermatocytic seminomas. In addition, a relatively frequent concomitant presence of somatic cell tumours was noted in canine TGCT. None of the canine TGCT evaluated demonstrated the presence of carcinoma in situ cells, a standard feature of human classical seminomas, suggesting that classical seminomas either do not occur in dogs or are rare in occurrence. Canine spermatocytic seminomas may provide a useful model for this rare human neoplasm.

Heterozygous deletion at the RLN1 locus in a family with testicular germ cell cancer identified by integrating copy number variation data with phenome and interactome information.

To search for disease-related copy number variations (CNVs) in families with a high frequency of germ cell tumours (GCT), we analysed 16 individuals from four families by array comparative genomic hybridization (aCGH) and applied an integrative systems biology algorithm that prioritizes risk-associated genes among loci targeted by CNVs. The top-ranked candidate, RLN1, encoding a Relaxin-H1 peptide, although only detected in one of the families, was selected for further investigations. Validation of the CNV at the RLN1 locus was performed as an association study using qPCR with 106 sporadic testicular GCT patients and 200 healthy controls. Observed CNV frequencies of 1.9% among cases and 1.5% amongst controls were not significantly different and this was further confirmed by CNV data extracted from a genome-wide analysis of 189 cases and 380 controls, where similar frequencies of 2.2% were observed in both groups (p=1). Immunohistochemistry for Relaxin-H1 (RLN1), Relaxin-H2 (RLN2) and their cognate receptor, RXFP1, detected one, and in some cases both, of the relaxins in Leydig cells, Sertoli cells and a subset of neoplastic germ cells, whereas the receptor was present in Leydig cells and spermatids. Collectively, the findings show that a heterozygous loss at the RLN1 locus is not a genetic factor mediating high population-wide risk for testicular germ cell tumour, but do not exclude a contribution of this aberration in some cases of cancer. The preliminary expression data suggest a possible role of the relaxin peptides in spermatogenesis and warrant further studies.

Screening of subfertile men for testicular carcinoma in situ by an automated image analysis-based cytological test of the ejaculate.

Testicular cancer (TC) is usually diagnosed after manifestation of an overt tumour. Tumour formation is preceded by a pre-invasive and asymptomatic stage, carcinoma in situ (CIS) testis, except for very rare subtypes. The CIS cells are located within seminiferous tubules but can be exfoliated and detected in ejaculates with specific CIS markers. We have built a high throughput framework involving automated immunocytochemical staining, scanning microscopy and in silico image analysis allowing automated detection and grading of CIS-like stained objects in semen samples. In this study, 1175 ejaculates from 765 subfertile men were tested using this framework. In 5/765 (0.65%) cases, CIS-like cells were identified in the ejaculate. Three of these had bilateral testicular biopsies performed and CIS was histologically confirmed in two. In total, 63 bilateral testicular biopsy were performed in conjunction with analysis of the ejaculates because of infertility work-up. Histological analysis of the biopsies for the presence of CIS yielded a test sensitivity of 0.67 and a specificity of 0.98. In addition, ejaculates from 45 patients with clinical signs of an overt TC were investigated and yielded a slightly lower sensitivity (0.51), possibly because of obstruction. We conclude that this novel non-invasive test combining automated immunocytochemistry and advanced image analysis allows identification of TC at the CIS stage with a high specificity, but a negative test does not completely exclude CIS. On the basis of the results, we propose that the assay could be offered to subfertile men and other patients who are at increased risk of TC.

Mapping the stem cell state: eight novel human embryonic stem and embryonal carcinoma cell antibodies.

The antigenic profile of human embryonic stem (ES) and embryonal carcinoma (EC) cells has served as a key element of their characterization, with a common panel of surface and intracellular markers now widely used. Such markers have been used to identify cells within the 'undifferentiated state', yet it appears that this categorization may be an oversimplification, because a number of sub-states appear to exist within this state. To increase the resolution of the undifferentiated state, we have generated eight novel monoclonal antibodies, all capable of recognizing undifferentiated human ES and EC cells, and herein describe their characterization. The reactivity of these antibodies against a range of cell lines is reported, as well as their developmental regulation, basic biochemistry and reactivity in immunohistochemistry of testicular germ cell tumours. Our data reveal a range of reactivity for all antibodies against both ES and EC cells, suggesting that these markers will afford recognition of unique sub-states within the undifferentiated stem cell compartment.

Carcinoma in situ testis displays permissive chromatin modifications similar to immature foetal germ cells.

BACKGROUND: The majority of testicular germ cell cancers develop through a pre-invasive carcinoma in situ (CIS) stage. The CIS cell is a neoplastic counterpart of foetal germ cells. During their development, foetal germ cells undergo extensive and essential epigenetic modifications, but little is known about epigenetic patterns in CIS cells. METHODS: Immunohistochemistry was used to investigate epigenetic patterns in CIS, germ cell tumours, normal adult and foetal testicular tissue. RESULTS: CIS cells show low levels of DNA methylation and repressive histone modifications H3K9me2 and H3K27me3, but high levels of H3K9 acetylation, H3K4 methylation and H2A.Z, which all are associated with an activated and accessible chromatin structure. Collectively this renders a permissive chromatin structure and in accordance high levels of RNA polymerase II activity and proliferation (Ki-67 and mitotic index) is observed in CIS cells. Epigenetic patterns similar to that of CIS cells were observed in human gonocytes present within sex cords in foetal testes but correspond to migrating primordial germ cell in mice. Development of overt tumours involves epigenetic repression of the chromatin. CONCLUSION: CIS cells have a permissive and foetal-like chromatin structure, which is associated with a high transcriptional and proliferative activity, likely empowering neoplastic transformation. Developmental epigenetic cues in foetal germ cells are substantially different between humans and mice.