A preliminary study investigating the detection of lymphovascular invasion in germ cell tumors of the testis with double staining for OCT4/CD34.

Lymphovascular invasion (LVI) is a relevant prognostic factor in germ cell tumors of the testis (GCTT) and it has been included in the AJCC staging system. Nevertheless, its histological assessment is challenging, with low/moderate interobserver agreement also among expert uropathologists. Few studies focused on the potential role of immunohistochemistry to solve this critical issue; as result, in current guidelines there is no indication for additional staining to detect this histological feature. In the present study, we investigated the detection of LVI invasion in a small cohort of GCTT with double staining for OCT4/CD34. Although our results need to be validated in larger case series with follow-up data, they suggest as OCT4/CD34 could be a useful tool for the histological assessment of these tumors, helping to identify some histological mimickers of LVI and modifying the pT/stage in a significant percentage of patients.

Role of HNF1ß in the differential diagnosis of yolk sac tumor from other germ cell tumors.

Identification of the yolk sac tumor (YST) component in germ cell tumors (GCT) may prove challenging, and highly sensitive and specific immunohistochemical markers are still lacking. Preliminary data from the literature suggest that HNF1ß may represent a sensitive marker of YST. The specificity of HNF1ß has not been addressed in GCT. A cohort of 49 YST specimens from 45 patients was designed, occurring either as pure tumors, or as a component of a mixed GCT. Immunohistochemistry was conducted on whole tumor sections using HNF1ß. SALL4, OCT4, CD30, CDX2, Cytokeratin 19, Glypican 3, and GATA3 were used for classification of the GCT components. Patients were mostly male (39/45), aged 14 months to 49 years, with primary testicular tumors (37/39), or primary mediastinal pure YSTs (2/39). All 6 primary tumors occurring in females (6/45) were pure ovarian YSTs; age range was 4 to 72 years. HNF1ß nuclear reactivity was seen in the YST component in all 49 tumors, with a moderate to strong nuclear pattern of staining. Embryonal carcinoma (EC, 0/32) and seminoma (0/6) were negative. Choriocarcinoma (6/6) showed faint focal cytoplasmic reactivity to HNF1ß but no nuclear staining. In teratomas, only enteric-type glands showed nuclear reactivity to HNF1ß (11/16). Therefore, HNF1ß sensitivity in YST component identification was 100% and specificity was 80%. Thus, in our experience, HNF1ß is a sensitive and reliable marker of the YST component in GCT, and allows distinction of YST from intricately admixed EC, especially in the diffuse embryoma pattern.

Ovarian dysgerminomas are characterised by frequent KIT mutations and abundant expression of pluripotency markers.

BACKGROUND: Ovarian germ cell tumours (OGCTs) typically arise in young females and their pathogenesis remains poorly understood. We investigated the origin of malignant OGCTs and underlying molecular events in the development of the various histological subtypes of this neoplasia. RESULTS: We examined in situ expression of stem cell-related (NANOG, OCT-3/4, KIT, AP-2gamma) and germ cell-specific proteins (MAGE-A4, NY-ESO-1, TSPY) using a tissue microarray consisting of 60 OGCT tissue samples and eight ovarian small cell carcinoma samples. Developmental pattern of expression of NANOG, TSPY, NY-ESO-1 and MAGE-A4 was determined in foetal ovaries (gestational weeks 13-40). The molecular genetic part of our study included search for the presence of Y-chromosome material by fluorescence in situ hybridisation (FISH), and mutational analysis of the KIT oncogene (exon 17, codon 816), which is often mutated in testicular GCTs, in a subset of tumour DNA samples. We detected a high expression of transcription factors related to the embryonic stem cell-like pluripotency and undifferentiated state in OGCTs, but not in small cell carcinomas, supporting the view that the latter do not arise from a germ cell progenitor. Bilateral OGCTs expressed more stem cell markers than unilateral cases. However, KIT was mutated in 5/13 unilateral dysgerminomas, whereas all bilateral dysgerminomas (n = 4) and all other histological types (n = 22) showed a wild type sequence. Furthermore, tissue from five phenotypic female patients harbouring combined dysgerminoma/gonadoblastoma expressed TSPY and contained Y-chromosome material as confirmed by FISH. CONCLUSION: This study provides new data supporting two distinct but overlapping pathways in OGCT development; one involving spontaneous KIT mutation(s) leading to increased survival and proliferation of undifferentiated oogonia, the other related to presence of Y chromosome material and ensuing gonadal dysgenesis in phenotypic females.

Association of intratubular seminoma and intratubular embryonal carcinoma with invasive testicular germ cell tumors.

The classification of intratubular germ cell neoplasia of the testis includes an unclassified type (IGCNU), in addition to various other intratubular lesions that show specific forms of differentiation, such as intratubular seminoma and intratubular embryonal carcinoma. Although IGCNU is recognized as a precursor lesion for testicular germ cell tumors, the relationship between differentiated types of intratubular germ cell neoplasia and invasive germ cell tumors of the testis is not well established. The aim of the present study was to examine the association between invasive testicular germ cell tumors and intratubular neoplastic lesions, with particular emphasis on differentiated types of intratubular germ cell neoplasia. The seminiferous tubules adjacent to 42 testicular germ cell tumors were evaluated for the presence of various forms of intratubular germ cell neoplasia. IGCNU was observed in 37 (88%) of 42 cases, whereas intratubular seminoma and intratubular embryonal carcinoma were seen in 19% and 7% of the cases, respectively. Intratubular seminoma was associated primarily with seminomas or mixed germ cell tumors with a seminomatous component, but was also present in a case of a nonseminomatous germ cell tumor. Intratubular embryonal carcinoma was associated exclusively with nonseminomatous germ cell tumors. All cases of intratubular embryonal carcinoma were identified morphologically and exhibited histologic features corresponding to traditional definitions of this lesion. No examples of intratubular embryonal carcinoma as defined by CD30 expression alone in the absence of an intratubular proliferation were observed. The presence of intratubular seminoma in a nonseminomatous germ cell tumor suggests that it is a true preinvasive lesion rather than a manifestation of intratubular spread of an established invasive seminoma. The low incidence of intratubular embryonal carcinoma supports the theory that most nonseminomatous germ cell tumors evolve initially as seminomas, rather than directly from a differentiated intratubular neoplastic lesion.

Cloning and expression during development of three murine members of the COUP family of nuclear orphan receptors.

We have isolated the murine homologs of the members of the COUP-family of steroid hormone receptors, COUP-TF1, ARP-1 and EAR2. The proteins encoded by the murine genes appeared to be highly conserved when compared to their human counterparts. The expression of COUP-TF1 and ARP-1 was induced during differentiation of P19 embryonal carcinoma (EC) cells into derivatives of all three germ layers. Retinoic acid (RA) treatment rapidly induced expression of both genes, while other methods of differentiation were less effective. Undifferentiated P19 cells were found to express EAR2 mRNA and the expression level was only slightly elevated by RA-treatment. In addition, we analyzed the expression in P19 cells of three members of the retinoid X receptor (RXR) family, which have been shown to heterodimerize with members of the COUP-family. During RA mediated differentiation of P19 cells, RXR alpha expression was induced while RXR beta expression was not modulated and RXR gamma expression was down regulated. Gel shift analysis revealed that in P19 cells the members of the COUP-family comprise the major portion of proteins binding to a RA-responsive direct repeat of the consensus steroid hormone receptor binding half site (AGGTCA) spaced by one nucleotide (DR + 1). The members of the COUP-family appeared to down regulate RA-induced activation of RA-response element-containing reporter constructs in a promoter context-dependent manner. The expression patterns of COUP-TF1, ARP-1 and EAR2 during development were investigated by in situ hybridization. In agreement with the results obtained in vitro, the three genes appeared to be expressed in tissues derived from all three germ layers. However, COUP-TF1 and ARP-1 were found to be expressed predominantly in the developing central nervous system in mutually exclusive domains. Furthermore, strong ARP-1 expression was detected in lung and kidney. Our data strongly suggest an important role for the members of the COUP-family in the hormonal control of gene expression regulating embryogenesis.

Primary embryonal carcinoma of the orbit in a 10-month-old female: a seven-year follow-up.

PURPOSE: Extra-gonadal germ cell tumors (GCTs) are rare and can be highly aggressive. If correctly identified and treated with multimodality chemotherapy, their prognosis can be significantly improved. We examined a 10 month-old female with primary embryonal carcinoma of the orbit. DESIGN: Case report and literature review. METHODS: Case study with 7-year follow-up and literature review of intracranial and intraorbital GCT cases. RESULTS: The patient presented with progressive proptosis and ophthalmoplegia. CT scan revealed an orbital apex mass and biopsy demonstrated a nongerminomatous GCT--an embryonal carcinoma. The patient is tumor-free 7 years after multimodality chemotherapy. She has mild amblyopia and a right micro esotropia. CONCLUSIONS: Nongonadal GCTs of the orbit can occur and should be considered in the differential diagnosis of a young child with proptosis and ophthalmoplegia. Five-year survival rates improve significantly with accurate identification and treatment.

Follistatin expression in ES and F9 cells and in preimplantation mouse embryos.

Activins are thought to play a role in mesoderm induction in amphibian development. Studies of the expression patterns of activin during mouse embryogenesis are consistent with the proposal that they are also involved in mesoderm formation in mammals. Activins are expressed both maternally and zygotically at preimplantation stages, and at postimplantation stages transcripts are present at high levels in the deciduum, suggesting that mesoderm is induced by maternally-derived activin. The functions of activin can be modulated by follistatin. At postimplantation stages follistatin is expressed in the deciduum in a pattern reciprocal to that of activin. In the embryo proper, follistatin transcripts are localized to the primitive streak region during gastrulation and later in the somites and in rhombomeres 2, 4 and 6 of the hindbrain. In this paper we show that follistatin, like activin, is expressed throughout pre-implantation mouse development. Transcripts are present at low levels in undifferentiated F9 and ES cells, but they increase greatly on differentiation of both cell types. Expression of activin mRNA is decreased in differentiated F9 and ES cells, and the simultaneous increase in follistatin may create an efficient and rapid means of decreasing levels of functional activin.

Expression of ghrelin and its functional receptor, the type 1a growth hormone secretagogue receptor, in normal human testis and testicular tumors.

Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHS-R), has been primarily linked to the central neuroendocrine regulation of GH secretion and food intake, although additional peripheral actions of ghrelin have also been reported. In this context, the expression of ghrelin and its cognate receptor has been recently demonstrated in rat testis, suggesting a role for this molecule in the direct control of male gonadal function. However, whether this signaling system is present in human testis remains largely unexplored. In this study we report the expression and cellular location of ghrelin and its functional receptor, the type 1a GHS-R, in adult human testis. In addition, evaluation of ghrelin and GHS-R1a immunoreactivity in testicular tumors and dysgenetic tissue is presented. The expression of the mRNAs encoding ghrelin and GHS-R1a was demonstrated in human testis specimens by RT-PCR, followed by direct sequencing. In normal testis, ghrelin immunostaining was demonstrated in interstitial Leydig cells and, at lower intensity, in Sertoli cells within the seminiferous tubules. In contrast, ghrelin was not detected in germ cells at any stage of spermatogenesis. The cognate ghrelin receptor showed a wider pattern of cellular distribution, with detectable GHS-R1a protein in germ cells, mainly in pachytene spermatocytes, as well as in somatic Sertoli and Leydig cells. Ghrelin immunoreactivity was absent in poorly differentiated Leydig cell tumor, which retained the expression of GHS-R1a peptide. In contrast, highly differentiated Leydig cell tumors expressed both the ligand and the receptor. The expression of ghrelin and GHS-R1a was also detected in dysgenetic Sertoli cell-only seminiferous tubules, whereas germ cell tumors (seminoma and embryonal carcinoma) were negative for ghrelin and were weakly positive for GHS-R1a. In conclusion, our results demonstrate that ghrelin and the type 1a GHS-R are expressed in adult human testis and testicular tumors. Overall, the expression of ghrelin and its functional receptor in human and rat testis, with roughly similar patterns of cellular distribution, is highly suggestive of a conserved role for this newly discovered molecule in the regulation of mammalian testicular function.

DNA methylation patterns in tumors derived from F9 cells resemble methylation at the blastula stage.

We show here that the genome of F9 teratocarcinoma cells growing in culture is heavily methylated but undergoes massive demethylation in tumors derived by subcutaneous injection of the cells. This demethylation occurs primarily in single copy gene sequences. As a result imprinted genes acquire their characteristic monoallelic methylation patterns while nonimprinted genes undergo demethylation. The overall methylation pattern in the tumors resembles the pattern observed in the mouse preimplantation embryo. The F9 cells in the tumors apparently recognize imprinted genes, distinguish them from non-imprinted genes and change the methylation of both gene classes to the pattern which characterizes the embryo. These cells therefore have the potential of providing an abundant source of protein factors involved in establishing the methylation pattern during embryo developments.

Complex demethylation patterns at Sp1 binding sites in F9 embryonal carcinoma cells.

The ubiquitous transcription factor Sp1 has been implicated in the mechanism which maintains CpG islands methylation-free. Plasmids containing GC boxes (Sp1 sites) were in vitro methylated at every CpG dinucleotide. After stable introduction into F9 embryonal carcinoma cells, we analysed the methylation of the sequence around the GC boxes with bisulphite sequencing. In agreement with restriction site analysis by other labs, we found preferential demethylation at GC box DNA versus control DNA. However, the bisulphite sequencing which permits the analysis of every CpG site on a given DNA molecule, revealed a complex pattern of methylated and unmethylated sites. Upon prolonged culture the pattern became simpler, with most sites demethylated but certain sites being consistently methylated.

OCT4 staining in testicular tumors: a sensitive and specific marker for seminoma and embryonal carcinoma.

OCT4 (POU5F1) is a transcription factor expressed in embryonic stem and germ cells and is involved in the regulation and maintenance of pluripotency. It has been detected in primary testicular germ cell tumors with pluripotent potential, seminoma, and embryonal carcinoma. We undertook immunohistochemical staining of OCT4 in a wide variety of primary testicular neoplasms (germ cell tumors and other tumors) to assess the specificity and usefulness of this marker as a diagnostic tool. We examined histologic sections from 91 primary testicular neoplasms, including 64 cases of mixed germ cell tumors containing embryonal carcinoma (54), seminoma (51), yolk sac tumor (38), mature teratoma (31), immature teratoma (20), and choriocarcinoma (15). In addition, we examined sections from spermatocytic seminomas (5), Leydig cell tumors (8), Sertoli cell tumors (6), unclassified sex-cord stromal tumors (4), adenomatoid tumors (2), testicular tumor of adrenogenital syndrome (1), and granulosa cell tumor (1). Each tumor was examined with hematoxylin and eosin staining and with antibodies to OCT4. In all cases of mixed germ cell tumor with components of embryonal carcinoma (54) and seminoma (51), there was greater than 90% nuclear staining of the embryonal carcinoma and seminoma tumor cells with little to no background staining. In all but 1 of these cases (embryonal carcinoma), there was strong (3+) staining intensity. The other germ cell tumor components (yolk sac tumor, mature teratoma, immature teratoma, and choriocarcinoma) showed no staining. Syncytiotrophoblast cells, which were present in 15 of the cases, were also completely negative, as were all 5 of the spermatocytic seminomas. The 22 cases of non-germ cell tumors were all immunohistochemically negative for OCT4. Fifteen of the 54 germ cell tumors containing embryonal carcinoma were also examined with antibodies to CD30. These embryonal carcinoma components were all positive for CD30 with staining of greater than 90% of the tumor cells but with variable staining intensity. We conclude that immunostaining with antibodies to OCT4 is a useful diagnostic tool in the identification of primary testicular embryonal carcinomas and "usual," but not spermatocytic, seminomas. OCT4 immunostaining has comparable sensitivity but greater consistency compared with CD30 in the diagnosis of embryonal carcinoma.

Gonadal malignant germ cell tumors express immunoreactive inhibin/activin subunits.

OBJECTIVE: Inhibin and activin are proteins produced by ovarian granulosa cells and testicular Sertoli cells and are members of the transforming growth factor-beta superfamily. Since increased circulating levels of immunoreactive inhibin were detected in women with malignant ovarian tumors, they were proposed as tumor markers for ovarian carcinoma. Immunohistochemical studies later confirmed the presence of inhibin and activin subunits in granulosa cell tumors and epithelial ovarian cancer, as well as in Sertoli and Leydig cell testicular cancer. However, there is discrepant information on the detection of inhibin and activin in malignant germ cell tumors (MGCT). The aim of the present study was to evaluate the immunohistochemical expression of the inhibin/activin alpha, betaA and betaB subunits in ovarian and testicular MGCT specimens using polyclonal antisera. METHODS: The ovarian tissue samples were composed of 19 MGCT, including dysgerminoma (n=18) and yolk sac tumor (n=1). The testis specimens included classic seminomas (n=20), embryonal carcinomas (n=7), choriocarcinomas (n=2), and yolk sac tumor (n=1). RESULTS: Ovarian and testicular malignant germ cell tumors expressed positive staining for inhibin/activin alpha, betaA and betaB subunits, with some variations between and within individual tumors: while ovarian dysgerminomas were diffusely positive for alpha, betaA and betaB, testicular tumors expressed alpha and betaB subunits, whereas betaA staining was weak. CONCLUSIONS: The present results show positive staining for inhibin/activin subunits in ovarian and testicular MGCT, suggesting a possible role in tumorigenesis with the resultant clinical implication.

p27 and cyclin E/D2 associations in testicular germ cell tumors: implications for tumorigenesis.

The cyclins are key regulators of cell cycle progression and cellular proliferation. We have previously shown that in testicular germ cell tumors, cyclin E expression correlates with more aggressive tumors, higher clinical stage, and the presence of pulmonary metastases. Here, we have examined the association between cyclin activation and the proliferative rate of the pluripotential testicular tumor cell. We have shown that in a panel of 30 testicular germ cell tumors, 15 cases (50%) expressed the cyclin dependent kinase inhibitor p27; of note, 13 of 14 embryonal carcinomas (93%) coexpressed cyclin E and p27, suggesting inhibition of this cyclin. We show that 25 of 30 (83%) of the testicular germ cell tumors express cyclin D2. Using immunoprecipitation assays from the embryonal carcinoma cell line NTera2 or from tumor cell extracts, we have shown that cyclin D2 is complexed with p27, consistent with its known ability to sequester and block the cyclin E inhibitory function of p27. From these results, we propose a model in testicular germ cell tumors, in particular embryonal carcinomas, whereby the overexpression of cyclin D2, a gene localized on chromosome 12p--a region of DNA amplification in germ cell tumors--leads to the functional sequestration of p27 in the presence of cyclin E and cyclin D2, thus favoring cellular proliferation.

Intratubular embryonal carcinoma.

Although intratubular embryonal carcinoma has been described adjacent to invasive embryonal carcinoma, to our knowledge it has not been reported as an isolated finding. We present in this report the histologic and immunohistochemical findings of 2 cases of intratubular embryonal carcinoma. One case was exclusively intratubular embryonal carcinoma without an invasive component in the same testis. A malignant mixed germ cell tumor in the contralateral testis had been previously excised. The second case is predominantly composed of intratubular embryonal carcinoma adjacent to a malignant mixed germ cell tumor. In one case, the intratubular embryonal carcinoma was immunoreactive for CD30, AE1/AE3, cytokeratin 7 focally, and p53. It was negative for cytokeratin 20, p21, and alpha-fetoprotein. These findings are strongly supportive of the opinion that intratubular embryonal carcinoma is the precursor of invasive embryonal carcinoma.

Fine-needle aspiration of testicular lesions: report of 17 cases.

In this article we report on our diagnostic experience of fine-needle aspiration biopsies (FNAB) performed on 17 patients with testicular lesions in the period from 1994-1998. The cytological diagnosis was consistent with seminoma in 7 cases, sex cord-stromal tumors in 3 cases (2 Sertoli cell tumors, 1 Leydig cell tumor), embryonal carcinoma in 3 cases, and yolk-sac tumor in 1 case; the other 3 patients were suffering from flogistic pathology. The cytological diagnosis was confirmed in all cases after surgery. According to our experience, ultrasound FNAB of testicular lesions proved to be a very reliable technique in predicting malignancy with high sensitivity and specificity. None of the patients developed local recurrences or inguinal lymph-node metastasis due to FNAB. Therefore, tumor stage classification (TNM) was not modified in any patient.

[Histopathological and immunohistochemical study of ovarian polyembryoma].

A case of polyembryoma which is rare in ovarian malignant germ cell tumors was reported. Microscopically, numerous and variable embryoid bodies, surrounded by embryonic hepatoid tissues, trophoblastic cells and multiple elements, were observed. The results of immunohistochemical analysis were: (1) alpha fetoprotein (AFP) was not only shown positive in yolk sac cells among the embryoid bodies, in the endoderm and in the margins of the ectodermal cells, but also in multiple elements in the mucinous matrix. (2) Hepatoid tissues reacted positively to AFP and alpha antitrypsin (AAT) as well as to hCG. (3) By using hCG and human placental lactogen (hPL) as markers it is proven that among trophoblastic cells of the tumor, not only syncytiotrophoblastic cells but also the intermediate cells and the cytotrophoblastic cells could be identified.

Ovarian malignant mixed germ cell tumor with clear cell carcinoma in a postmenopausal woman.

Malignant germ cell tumors of the ovary are very rare and account for about 2-5% of all ovarian tumors of germ origin. Most patients are adolescent and young women, approximately two-thirds of them are under 20 years of age, occasionally in postmenopausal women. But clear cell carcinoma usually occurs in older patients (median age: 57-year old), and closely related with endometriosis. Here we report a case of a 55-year old woman with right ovarian mass that discovered by B ultrasonic. Her serum levels of human chorionic gonadotropin (hCG) and α-fetoprotein (AFP) were elevated. Pathological examination revealed the tumor to be a mixed germ cell tumor (yolk sac tumor, embryonal carcinoma and mature teratoma) with clear cell carcinoma in a background of endometriosis. Immunohistochemical staining showed SALL4 and PLAP were positive in germ cell tumor area, hCG, CD30 and OCT4 were positive in epithelial-like cells and giant synctiotrophoblastic cells, AFP, AAT, CD117 and Glyp3 were positive in yolk sac component, EMA and CK7 were positive in clear cell carcinoma, CD10 was positive in endometrial cells of endometriotic area. She was treated with surgery followed by seven courses of chemotherapy. She is well and serum levels of hCG and AFP have been decreased to normal levels.

The utility of microscopic findings and immunohistochemistry in the classification of necrotic testicular tumors: a study of 11 cases.

Necrotic testicular tumors are relatively frequent and can present a significant diagnostic challenge. Because of differing treatments for seminomas versus nonseminomas, accurate diagnosis is critical. Eleven totally (n=9) or almost totally (n=2) necrotic testicular tumors were retrieved from our consult files. The submitting pathologists favored benign processes in 4 cases, Leydig cell tumor in 1, and lymphoma in 1. The cases were evaluated for histologic features and, when material was available, by immunostaining with 7 antibodies: keratin (AE1/AE3), OCT4, placental alkaline phosphatase, alpha-fetoprotein (AFP), CD117, CD30, and S100. Only distinct reactivity in a cellular distribution in the necrotic zone was considered positive; nuclear reactivity alone was scored for OCT4 and membrane reactivity for CD117 and CD30. Mean patient age was 35 years (range 16-63). Mean tumor size was 19 mm (range 7-53). All patients presented with unilateral testicular masses (6 right, 5 left); 2 also had acute pain. The combination of histologic features, immunostains and, in 1 case, serum AFP permitted classification of 8 tumors (4 seminomas, 3 embryonal carcinomas, 1 yolk sac tumor). Three were not classifiable. The necrotic seminomas lacked associated coarse intratubular calcifications and were positive for OCT4 (4/4) and CD117 (3/3) but negative for keratin (0/4) and CD30 (0/4). The necrotic embryonal carcinomas had associated coarse intratubular calcifications and were positive for keratin (2/3), OCT4 (2/2), and CD30 (3/3). OCT4 stained 1 unclassifiable tumor, which lacked other specific markers. We did not find placental alkaline phosphatase, AFP, and S100 stains useful, although S100 did highlight tumor "ghost" cells in 1 case. Other features in most cases included intratubular germ cell neoplasia (6/11), tubular atrophy/hyalinization (10/11), tumor "ghost" cells (10/11), scar (9/11), and inflammation (10/11). Of the 5 patients with available follow-up, 3 were free of disease at 1, 5, and 8 years after orchiectomy (2 necrotic seminomas and 1 germ cell tumor, unclassified). One patient with yolk sac tumor (age 63 y) developed widespread metastases after 15 months and died of disease. The final case was initially misinterpreted as "testicular infarction, no malignancy" and 16 months later the patient developed a large retroperitoneal seminoma. Most totally necrotic testicular tumors can be placed into clinically important groups by assessment for coarse intratubular calcifications and staining reactions for keratin, OCT4, CD117, and CD30.

Expression of IGF-II mRNA-binding proteins (IMPs) in gonads and testicular cancer.

Insulin-like growth factor-II mRNA-binding proteins 1, 2 and 3 (IMP1, IMP2 and IMP3) belong to a family of RNA-binding proteins implicated in mRNA localization, turnover and translational control. We examined their expression pattern during development of murine and human testis and ovaries. In the mouse, IMPs were expressed in male and female gonadal cells at embryonic day 12.5 (E12.5). From E16.5, IMP1 and IMP3 became restricted to the developing germ cells, whereas IMP2 expression persisted in the interstitial cells. In mature mouse and human ovaries, IMP1, IMP2 and IMP3 were detected in resting and growing oocytes and in the granulosa cells. In testis, IMP1 and IMP3 were found mainly in the spermatogonia, whereas IMP2 was expressed in the immature Leydig cells. Moreover, all three IMPs were detected in human semen. The developmental expression pattern of IMP1 and IMP3 in the human testis prompted us to examine their possible involvement in testicular neoplasia. IMPs were detected primarily in germ-cell neoplasms, including preinvasive testicular carcinoma in situ, classical and spermatocytic seminoma, and nonseminomas, with particularly high expression in undifferentiated embryonal carcinoma. The relative expression of IMP1, IMP2 and IMP3 varied among tumor types and only IMP1 was detected in all carcinoma in situ cells. Thus IMPs, and in particular IMP1, may be useful auxiliary markers of testicular neoplasia.

t-complex-associated embryonic surface antigen homologous to mLAMP-1. I. Biochemical and molecular analyses.

Previously we described an embryonic cell surface glycoprotein, ESGp, associated with the t-embryonic lethal alleles of the mouse t complex. This antigen is expressed on the cell surface of both early mouse embryos and embryonal carcinoma (EC) cell lines. The antigen is localized to areas of cell-cell contact in EC lines and redistributes to the outer edges of the blastomeres during compaction, thereby indicating a potential role in embryonic cell-cell interaction. We now report that this t-complex-associated ESGp is homologous to the mouse lysosomal-associated membrane protein-1 (LAMP-1). Limited protein sequence analyses of the amino terminal and an internal peptide indicate considerable homology with the LAMP-1 protein. Biochemical parameters such as protein core size, sulfation and phosphorylation status, and resistance to proteolysis also demonstrate homology. While we detect only a single message with a mouse LAMP-1 cDNA probe via Northern blotting, Southern analyses indicate the existence of at least two homologous LAMP-1 genes. Additionally, we present evidence suggesting that ESGp/LAMP-1 serves as a substrate which may be differentially glycosylated by the activities of the gene products of the different t-lethal alleles.