Association between glutathione S-transferases M1 expression and treatment outcome in germ cell tumor patients.

Cisplatin-based chemotherapy is the mainstay in the treatment of germ cell tumors (GCTs). Glutathione S-transferases (GSTs) are polymorphic enzymes that catalyze the glutathione conjugation of alkylating agents, platinum compounds, and free radicals formed by chemotherapy and are thus implicated in developing treatment resistance. This study aimed to assess the expression level of GST mu 1 (GSTM1) and its association with treatment outcomes in patients with GCT. This translational study included tumor specimens from 207 patients with newly diagnosed GCTs, as well as cisplatin-sensitive GCT cell line xenografts and their resistant variants for all histological variants of GCTs. GSTM1 expression was detected by reverse transcription-quantitative PCR and immunohistochemistry using monoclonal antibodies, scored by the multiplicative quickscore (QS) method. GSTM1 expression was correlated with patient/tumor characteristics and treatment outcomes. The highest GSTM1 expression was observed in seminoma, followed by choriocarcinoma, embryonal carcinoma, and yolk sac tumor, while the lowest was observed in teratoma (p<0.0001). There was no association between GSTM1 expression in tumor tissue and patient/tumor characteristics. The low GSTM1 expression was associated with significantly better relapse-free survival compared with high GSTM1 (HR=0.50, 95% CI 0.23-1.09, p=0.03) but not overall survival (HR=0.61, 95% CI 0.24-1.54, p=0.22). Multivariate analysis showed that the prognostic value of GSTM1 was independent of the International Germ Cell Cancer Collaborative Group (IGCCCG) score. These data revealed the prognostic value of GSTM1 in GCTs, with a high GSTM1 expression associated with worse outcomes, suggesting that GSTM1 could be responsible, in part, for treatment resistance in GCTs.

AGR2 facilitates teratoma progression by regulating glycolysis via the AnXA2/EGFR axis.

Anterior gradient-2 (AGR2) is highly expressed in several tumors and plays an important role in tumor development. However, the biological function of AGR2 in teratomas has not yet been thoroughly studied. In this study, AGR2 was found to be upregulated in teratoma tissues and in human testicular teratoma cell lines by Western blotting and qRT-PCR assays. A DNA Methylation-Specific PCR assay demonstrated that AGR2 upregulation resulted from hypomethylated AGR2 in teratoma cells. NCC-IT and NT2-D1 cells were transfected with pcDNA-AGR2 or sh-AGR2 to obtain AGR2-overexpressed or -silenced cells, and cell proliferation, invasion and glycolysis were determined using CCK-8, 5-ethynyl-2'-deoxyuridine (EdU), Transwell assays, and commercial kits. The results revealed that overexpression of AGR2 promoted teratoma cell proliferation and invasion and elevated glycolysis levels evidencing by the increase in lactate secretion, glucose consumption, ATP levels and the expression of glycolysis-related proteins, while knockdown of AGR2 showed the opposite results. The interactions between AGR2 and annexin A2 (AnXA2), as well as between AnXA2 and epidermal growth factor receptor (EGFR) were verified by co-immunoprecipitation assay. Mechanistic studies revealed that AGR2 interacts with AnXA2 and increases the level of AnXA2 to recruit more AnXA2 to EGFR, there by promoting EGFR expression. A series of rescue experiments showed that knockdown of AnXA2 or EGFR weakened the promotional effects of AGR2 overexpression on the proliferation, invasion, and glycolysis of teratoma cells. Finally, tumorigenicity assays were performed using NT2-D1 cells stably transfected with either LV-NC-shRNA or LV-shAGR2. The results showed that AGR2 knockdown significantly inhibited teratoma tumor growth in vivo. In conclusion, our data suggested that AGR2 facilitates glycolysis in teratomas through promoting EGFR expression by interacting with AnXA2, thereby promoting teratoma cells proliferation and invasion.

Understanding the role of endocrine disrupting chemicals in testicular germ cell cancer: Insights into molecular mechanisms.

This comprehensive review examines the complex interplay between endocrine disrupting chemicals (EDCs) and the development of testicular germ cell tumors (TGCTs). Despite the high cure rates of TGCTs, challenges in diagnosis and treatment remain, necessitating a deeper understanding of the etiology of the disease. Here, we emphasize current knowledge on the role of EDCs as potential risk factors for TGCTs, focusing on pesticides and perfluorinated and polyfluoroalkyl substances (PFAs/PFCs). Evidence suggests that EDCs disrupt endocrine pathways and induce epigenetic changes that contribute to the development of TGCTs. However, the direct link between EDCs and TGCTs remains elusive and requires further investigation of the molecular mechanisms. We also highlighted the importance of studying nuclear receptors as potential targets for understanding TGCT etiology. In addition, recent evidence implicates PFAs/PFCs in TGCT incidence, highlighting the need for further research into their impact on human health. Overall, this review provides valuable insights into the potential role of EDCs in TGCT development and suggests avenues for future research, while also highlighting how understanding their influence may pave the way for novel therapeutic approaches to improve disease management.

Expression of Podocalyxin Potentially Decorated With Low-sulfated Keratan Sulfate in Human Testicular Embryonal Carcinoma.

SummaryWe previously demonstrated that among various histological types of human testicular germinal cell tumors (GCTs), embryonal carcinoma (EC) preferentially expresses low-sulfated keratan sulfate (KS) consisting of repeating N-acetyllactosamine (LacNAc) disaccharide units composed of galactose and 6-O-sulfated N-acetylglucosamine (GlcNAc), which is recognized by the R-10G antibody. Recently, we generated another anti-low-sulfated KS monoclonal antibody, 294-1B1. Immunohistochemical analysis of testicular GCTs (n=83) revealed that the low-sulfated KS recognized by 294-1B1 is also preferentially expressed in EC but minimally in other GCT histological types. Moreover, immunolabeling with R-10G and 294-1B1 antibodies was resistant to peptide-N-glycosidase F digestion, and EC was not stained with the MECA-79 antibody, indicating that low-sulfated KS expressed in EC contains mucin-type core 2 O-glycans carrying GlcNAc-6-O-sulfated oligo-LacNAc. Double immunofluorescence staining showed that R-10G and 294-1B1 antibody signals colocalized with those for podocalyxin (PODXL). Furthermore, western blot analysis of recombinant human PODXL•IgG fusion proteins secreted from low-sulfated KS-expressing human embryonic kidney 293T cells revealed that PODXL functions as a core protein for low-sulfated KS. Taken together, these findings strongly suggest that the PODXL glycoform decorated with low-sulfated KS is preferentially expressed in human testicular EC and may therefore serve as a diagnostic marker for this malignancy.

Defining the cellular origin of seminoma by transcriptional and epigenetic mapping to the normal human germline.

Aberrant male germline development can lead to the formation of seminoma, a testicular germ cell tumor. Seminomas are biologically similar to primordial germ cells (PGCs) and many bear an isochromosome 12p [i(12p)] with two additional copies of the short arm of chromosome 12. By mapping seminoma transcriptomes and open chromatin landscape onto a normal human male germline trajectory, we find that seminoma resembles premigratory/migratory PGCs; however, it exhibits enhanced germline and pluripotency programs and upregulation of genes involved in apoptosis, angiogenesis, and MAPK/ERK pathways. Using pluripotent stem cell-derived PGCs from Pallister-Killian syndrome patients mosaic for i(12p), we model seminoma and identify gene dosage effects that may contribute to transformation. As murine seminoma models do not exist, our analyses provide critical insights into genetic, cellular, and signaling programs driving seminoma transformation, and the in vitro platform developed herein permits evaluation of additional signals required for seminoma tumorigenesis.

Molecular and epigenetic ex vivo profiling of testis cancer-associated fibroblasts and their interaction with germ cell tumor cells and macrophages.

Germ cell tumors (GCT) are the most common solid tumors in young men of age 15 - 40. In previous studies, we profiled the interaction of GCT cells with cells of the tumor microenvironment (TM), which showed that especially the 3D interaction of fibroblasts (FB) or macrophages with GCT cells influenced the growth behavior and cisplatin response as well as the transcriptome and secretome of the tumor cells, suggesting that the crosstalk of these cells with GCT cells is crucial for tumor progression and therapy outcome. In this study, we shed light on the mechanisms of activation of cancer-associated fibroblasts (CAF) in the GCT setting and their effects on GCT cells lines and the monocyte cell line THP-1. Ex vivo cultures of GCT-derived CAF were established and characterized molecularly and epigenetically by performing DNA methylation arrays, RNA sequencing, and mass spectrometry-based secretome analysis. We demonstrated that the activation state of CAF is influenced by their former prevailing tumor environment in which they have resided. Hereby, we postulate that seminoma (SE) and embryonal carcinoma (EC) activate CAF, while teratoma (TER) play only a minor role in CAF formation. In turn, CAF influence proliferation and the expression of cisplatin sensitivity-related factors in GCT cells lines as well as polarization of in vitro-induced macrophages by the identified effector molecules IGFBP1, LGALS3BP, LYVE1, and PTX3. Our data suggests that the vital interaction of CAF with GCT cells and with macrophages has a huge influence on shaping the extracellular matrix as well as on recruitment of immune cells to the TM. In conclusion, therapeutically interfering with CAF and / or macrophages in addition to the standard therapy might slow-down progression of GCT and re-shaping of the TM to a tumor-promoting environment. Significance: The interaction of CAF with GCT and macrophages considerably influences the microenvironment. Thus, therapeutically interfering with CAF might slow-down progression of GCT and re-shaping of the microenvironment to a tumor-promoting environment.

Comprehensive microRNA expression analysis of pediatric gonadal germ cell tumors: unveiling novel biomarkers and signatures.

microRNAs (miRNAs) are small endogenous noncoding RNAs, and alterations in their expression may contribute to oncogenesis. Discovering a unique miRNA pattern holds the potential for early detection and novel treatment possibilities in cancer. This study aimed to evaluate miRNA expression in pediatric patients with gonadal germ cell tumors (GCTs), focusing on characterizing the miRNA profiles of each histological subtype and identifying a distinct histological miRNA signature for a total of 42 samples of pediatric gonadal GCTs. The analysis revealed distinct miRNA expression profiles for all histological types, regardless of the primary site. We identified specific miRNA expression signatures for each histological type, including 34 miRNAs for dysgerminomas, 13 for embryonal carcinomas, 25 for yolk sac tumors, and one for immature teratoma, compared to healthy controls. Furthermore, we identified 26 miRNAs that were commonly expressed in malignant tumors, with six miRNAs (miR-302a-3p, miR-302b-3p, miR-371a-5p, miR-372-3p, miR-373-3p, and miR-367-3p) showing significant overexpression. Notably, miR-302b-3p exhibited a significant association with all the evaluated clinical features. Our findings suggest that miRNAs have the potential to aid in the diagnosis, prognosis, and management of patients with malignant GCTs.

NANOG controls testicular germ cell tumour stemness through regulation of MIR9-2.

BACKGROUND: Testicular germ cell tumours (TGCTs) represent a clinical challenge; they are most prevalent in young individuals and are triggered by molecular mechanisms that are not fully understood. The origin of TGCTs can be traced back to primordial germ cells that fail to mature during embryonic development. These cells express high levels of pluripotency factors, including the transcription factor NANOG which is highly expressed in TGCTs. Gain or amplification of the NANOG locus is common in advanced tumours, suggesting a key role for this master regulator of pluripotency in TGCT stemness and malignancy. METHODS: In this study, we analysed the expression of microRNAs (miRNAs) that are regulated by NANOG in TGCTs via integrated bioinformatic analyses of data from The Cancer Genome Atlas and NANOG chromatin immunoprecipitation in human embryonic stem cells. Through gain-of-function experiments, MIR9-2 was further investigated as a novel tumour suppressor regulated by NANOG. After transfection with MIR9-2 mimics, TGCT cells were analysed for cell proliferation, invasion, sensitivity to cisplatin, and gene expression signatures by RNA sequencing. RESULTS: For the first time, we identified 86 miRNAs regulated by NANOG in TGCTs. Among these, 37 miRNAs were differentially expressed in NANOG-high tumours, and they clustered TGCTs according to their subtypes. Binding of NANOG within 2 kb upstream of the MIR9-2 locus was associated with a negative regulation. Low expression of MIR9-2 was associated with tumour progression and MIR9-2-5p was found to play a role in the control of tumour stemness. A gain of function of MIR9-2-5p was associated with reduced proliferation, invasion, and sensitivity to cisplatin in both embryonal carcinoma and seminoma tumours. MIR9-2-5p expression in TGCT cells significantly reduced the expression of genes regulating pluripotency and cell division, consistent with its functional effect on reducing cancer stemness. CONCLUSIONS: This study provides new molecular insights into the role of NANOG as a key determinant of pluripotency in TGCTs through the regulation of MIR9-2-5p, a novel epigenetic modulator of cancer stemness. Our data also highlight the potential negative feedback mediated by MIR9-2-5p on NANOG expression, which could be exploited as a therapeutic strategy for the treatment of TGCTs.

Expression of CD44 is associated with aggressiveness in seminomas.

BACKGROUND: Testicular germ cell tumors (TGCTs) exhibit diverse biological and pathological features and are divided in two main types, seminomas and nonseminomatous germ cell tumors (NSGCTs). CD44 is a cell surface receptor, which is highly expressed in malignancies and is implicated in tumorigenesis affecting cell-matrix interactions and cell signaling. METHODS AND RESULTS: Here, we examined the expression of CD44 in tumor cell lines and in patients' material. We found that CD44 is over-expressed in TGCTs compared to normal tissues. Immunohistochemical staining in 71 tissue specimens demonstrated increased expression of CD44 in some patients, whereas CD44 was absent in normal tissue. In seminomas, a high percentage of tumor and stromal cells showed cytoplasmic and/or cell surface staining for CD44 as well as increased staining for CD44 in the tumor stroma was found in some cases. The increased expression of CD44 either in tumor cells or in stromal components was associated with tumor size, nodal metastasis, vascular/lymphatic invasion, and disease stage only in seminomas. The increased stromal expression of CD44 in TGCTs was positively associated with angiogenesis. CONCLUSIONS: CD44 may exhibit diverse biological functions in seminomas and NSGCTs. The expression of CD44 in tumor cells as well as in tumor stroma fosters an aggressive phenotype in seminomas and should be considered in disease treatment.

Human benign Leydig cell tumor - Biochemical evaluation.

Recently we reported expressional alterations in 219 genes and their transcripts in Leydig cell tumors but nowadays there is still a lack of full basic biochemical characteristics of these tumors. The discovery of potential biochemical markers for tumor management from early detection, treatments, and control of therapy results may markedly supplement genetic data. Leydig cell micronodules were obtained from patients with azoospermia who were qualified for testicular biopsy. The biochemistry of Leydig cell tumors was analyzed using histological staining and spectrophotometric measurements of total proteins, carbohydrates, lipids, and nucleic acids. In addition, the levels of calcium (Ca2 +), copper (Cu2 +), zinc (Zn2 +), and selenium (Se2 +) ions were measured. When compared to healthy testis we revealed, for the first time, that in the interstitial tissue with Leydig cell tumors, great amounts of proteins, carbohydrates, lipids, and acids were dislocated from the seminiferous tubules. Measurements of organic compounds showed a decrease (P < 0.05) only in the Cu2 + content in Leydig cell tumors which may be related to their altered biochemical structure. This specific result may be promising for designing further approaches to manage this tumor based on combining morphological and molecular data.

Primitive Embryonic-Type Neuroectodermal/Glandular Complexes in Testicular Germ Cell Tumors: A Mimic of Embryonic-Type Neuroectodermal Tumor.

Embryonic-type neuroectodermal elements are often intimately mixed with primitive endodermal-type glands, like those of yolk sac tumors, in germ cell neoplasia in situ (GCNIS)-derived germ cell tumors of the testis. Because the primitive glands mimic tubules or rosettes of embryonic-type neuroectodermal elements, these embryonic-type neuroectodermal/glandular complexes may be misinterpreted as pure lesions of embryonic-type neuroectodermal elements, which, if of sufficient size, may lead to a diagnosis of embryonic-type neuroectodermal tumor, despite that the criteria of the World Health Organization for a "somatic-type malignancy" are not met. A diagnosis of embryonic-type neuroectodermal tumor in the testis may lead to retroperitoneal lymphadenectomy even in clinical stage I patients, and in postchemotherapy resections indicates a poor prognosis. The distinction of the neuroectodermal and glandular elements is not always straightforward based on morphology alone. We, therefore, studied 34 testis-derived germ cell tumors with embryonic-type neuroectodermal/glandular complexes and 2 purely glandular yolk sac tumors to characterize the immunophenotypes and determine an efficient immunohistochemical panel to aid in this differential. We found that GFAP, synaptophysin, and paired-like homeobox 2B (PHOX2B) expression was specific to embryonic-type neuroectodermal elements, although PHOX2B had poor sensitivity. In contrast, positive reactions with antibodies directed against AFP, villin, and CDX2 were specific for the glandular elements, although CDX2 had poor sensitivity. Other markers, including AE1/AE3 cytokeratin, SALL4, glypican 3, SOX2, SOX11, CD56, INSM1, and neurofilament, proved less helpful because of their nonspecificity and/or poor sensitivity. We conclude that the optimal immunohistochemical panel for distinguishing the components of embryonic-type neuroectodermal/glandular complexes includes stains for synaptophysin, GFAP, villin, and AFP.

Higher expression of SALL4-A isoform is correlated with worse outcomes and progression of the disease in subtype of testicular germ cell tumours.

BACKGROUND: The transcription factor SALL4 is associated with embryonic pluripotency and has proposed as a novel immunohistochemistry (IHC) marker for diagnosing germ cell tumours. SALL4 comprises three isoforms, and SALL4-A being the full-length isoform. Studying its isoforms could revolutionize testicular cancer prognosis and subtype differentiation. METHODS: The expression and clinical significance of isoform 'A' of SALL4 was evaluated in 124 testicular germ cell tumours (TGCTs) subtypes, adjacent 67 normal tissues and 22 benign tumours, using immunohistochemistry on tissue microarrays (TMA). RESULTS: A statistically significant higher expression of nuclear and cytoplasmic SALL4-A was detected in TGCTs histological subtypes and benign tumours compared to the normal tissues. Seminoma and yolk sac tumours had the highest nuclear and cytoplasmic expression of SALL4-A. A significant correlation was detected between the higher nuclear expression of SALL4-A and increased pT stages (P = 0.026) in seminomas. Whereas in embryonal carcinomas, cytoplasmic expression of SALL4-A was associated with the tumour recurrence (P = 0.04) and invasion of the epididymis (P = 0.011). CONCLUSIONS: SALL4-A isoform expression in the cytoplasm and nucleus of TGCTs may be associated with histological differentiation. In the seminoma subtype of TGCTs, higher expression of SALL4-A may be used as a predictive indicator of poorer outcomes and prognosis.

Estrogen receptor beta expression and role in cancers.

Estrogen drives the growth of some cancers, such as breast cancer, via estrogen receptor alpha (ERα). Estrogen also activates ERß, but whether ERß is expressed and has a role in different cancers is debated. The use of nonspecific antibodies has contributed to the confusion, and this review delves into ERß's controversial role in cancer and focuses on tumor expression that can be supported by non-antibody-dependent assays. We discuss its expression at the transcript level and focus on its potential role in lymphoma, granulosa cell tumors, testicular, and adrenal cancers, emphasizing recent findings and the complexities that necessitate further research.

ß-Catenin alterations in testicular Leydig cell tumour: a immunohistochemical and molecular analysis.

BACKGROUND: Testicular Leydig cell tumours (LCTs) are the most common type of sex cord-stromal tumour in men, representing 1%-3% of all testicular neoplasms. Among testicular sex cord-stromal tumours, CTNNB1 mutations and nuclear expression of ß-catenin have been typically associated with Sertoli cell tumour. Recent genomic analyses have shown that CTNNB1 variants are also identified in a subset of LCTs; however, the frequency and clinicopathologic associations of ß-catenin alterations remain incompletely understood in this tumour type. METHODS: In this study, we evaluated 32 LCTs (five malignant/metastasizing, 27 nonmetastasizing) using ß-catenin immunohistochemistry and DNA sequencing. RESULTS: Immunohistochemistry revealed focal or multifocal nuclear ß-catenin expression in 47% of the tumours. Diffuse nuclear ß-catenin expression (in >50% of the tumour cells) was not detected in any of the cases analysed herein. Comparison of ß-catenin-positive and ß-catenin-negative cases did not show significant differences in the frequency of adverse histopathologic findings or malignant clinical behaviour. DNA sequencing performed de novo on a subset of seven cases revealed the presence of exon 3 CTNNB1 variants in four of them (4/7, 57%), with variant allele frequencies (VAF) ranging from 7 to 33%. Two additional ß-catenin-positive cases that had been sequenced as part of a previous study harboured exon 3 CTNNB1 variants at VAF of 28% and 7%, respectively. CONCLUSION: These results demonstrate that ß-catenin alterations are relatively common in LCT, most likely occurring as subclonal events that are not enriched in cases with aggressive features. Further studies are needed to clarify the oncogenic role of ß-catenin in this tumour type.

68 Ga-PSMA Uptake in the Testis : Two Different Patients With Two Different Diagnosis.

ABSTRACT: Although abnormal 68 Ga-PSMA uptake in the prostate and its metastases can be seen in a variety of diseases, it is rare to see in the testis. In these 2 cases, 68 Ga-PSMA PET/CT revealed unilateral 68 Ga-PSMA uptake in the testis of 2 patients. One of these patients was diagnosed with testis metastases from prostate cancer after an orchiectomy. The other patient was diagnosed with an orchitis. 68 Ga-PSMA uptake should be considered as an infection, as well as a malignancy in the initial differential diagnosis.

New analysis of atypical spermatocytic tumours reveals extensive heterogeneity and plasticity of germ cell tumours†.

Testicular germ cell tumours (TGCTs) derived from immature (type I) and pluripotent germ cell neoplasia in situ (GCNIS, type II) are characterised by remarkable phenotypic heterogeneity and plasticity. In contrast, the rare spermatocytic tumour (SpT, type III), derived from mature spermatogonia, is considered a homogenous and benign tumour but may occasionally present as an anaplastic or an aggressive sarcomatoid tumour. While various oncogenic processes had been proposed, the precise mechanism driving malignant progression remained elusive until the molecular characterisation of a series of atypical SpTs described in a recent issue of The Journal of Pathology. The emerging picture suggests the presence of two distinct trajectories for SpTs, involving either RAS/mitogen-activated protein kinase pathway mutations or a ploidy shift with secondary TP53 mutations and/or gain of chromosome 12p, the latter known as pathognomonic for type II GCNIS-derived TGCTs. Here, we discuss the implications of these findings, seen from the perspective of germ cell biology and the unique features of different TGCTs. The evolving phenotype of SpTs, induced by genomic and epigenetic changes, illustrates that the concept of plasticity applies to all germ cell tumours, making them inherently heterogenous and capable of significant transformation during progression. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Frequent expression of CD45RO memory T cell marker as well as low to high expression of PD-1 and PD-L1 inhibitory molecules in seminoma and dysgerminoma.

BACKGROUND: Seminoma and dysgerminoma are rare testicular and ovarian germ cell tumors characterized by a significant infiltration of immune cells in the tumor microenvironment. According to the failure of conventional treatments in some patients, it is crucial to identify novel prognostic and therapeutic biomarkers for these patients. The objectives of this study were to evaluate the expression of CD45RO and PD-1/PD-L1 and investigate their association with the clinicopathological characteristics of the patients. METHODS: Immunohistochemistry was performed to assess the expression of CD45RO, PD-1, and PD-L1 in tumor-infiltrated lymphocytes (TILs), and tumor cells in 33 seminoma and 31 dysgerminoma patients. The expression levels were evaluated using a semiquantitative approach, weighted histoscore, which considers both the intensity and extent of staining. RESULTS: All seminoma and dysgerminoma patients exhibited CD45RO expression in TILs, with 66.7 % and 90.3 % displaying high levels of expression, respectively. PD-1 expression in TILs was observed at low levels in 81.8 % and 77.4 % and at high levels in 18.2 % and 19.4 % of seminoma and dysgerminoma patients, respectively. Likewise, low expression of PD-L1 in tumor cells was detected in 63.6 % of seminoma and 61.3 % of dysgerminoma patients, while none of the patients exhibited high expression of PD-L1. In seminoma patients, a positive correlation was observed between PD-1 expression in TILs and CD45RO expression and between PD-L1 expression in tumor cells and TILs score. CONCLUSION: The frequent infiltration of CD45RO, along with variable expression of PD-1 and PD-L1 on TILs and tumor cells, could impact the effectiveness of anti-tumor responses and immunotherapy.

Predictive tissue markers in testicular germ cell tumors: Immunohistochemical expression of MLH1 and REV-7 proteins.

PURPOSE: Testicular Germ Cell Tumors (TGCTs) are the most frequent solid malignancies in young adult men. Regardless of differences in their cell of origin, all TGCTs are considered highly curable malignancies. However, approximately 3-5% of all TGCTs do not respond to platinum-based chemotherapies. The purpose of our paper is to investigate whether immunohistochemical expression of MLH1 and REV-7 can be used as predictive tissue markers for TGCTs. MATERIAL AND METHODS: The main demographic and clinicopathological characteristics of 64 male patients with TGCTs who underwent orchiectomy from 2007 to 2022 were retrospectively obtained from two large Oncology Clinics in Greece. Both patients with chemosensitive and chemoresistant disease were included. Immunohistochemical staining for MLH1 and REV-7 proteins was applied in specimens of these patients. RESULTS: 31 seminomas and 33 non-seminomas were included. 48 patients had chemosensitive disease, while 16 had chemoresistant disease. 53 specimens showed preserved MLH1 expression, while 11 specimens had lost MLH1 expression. Expression of MLH1 was only significantly associated with patients' age. 16 specimens showed positive REV-7 expression, while 48 specimens were REV-7 negative. Interestingly, 50% of patients with chemoresistant disease and 16,7% of patients with chemosensitive disease were REV-7 positive. This difference was statistically significant. Moreover, REV-7 positivity was significantly associated with chemoresistance, various clinicopathological parameters and patients' prognosis and survival. CONCLUSION: Loss of MLH1 expression was only found to be significantly associated with lower patients' age. Positive immunohistochemical REV-7 expression was significantly associated with various clinicopathological parameters, while it was also associated with significantly lower survival and greater hazard. REV-7 positive percentages were significantly higher in patients with chemoresistant disease. Our findings imply that immunohistochemical staining for REV-7 could potentially be used as a predictive tissue marker for TGCT tumors. Moreover, targeting of REV-7 protein, could represent a potential therapeutic strategy for chemoresistant TGCT cases. The implementation of well-designed studies on a larger scale is of utmost importance, in order to draw safer conclusions. Additional studies are needed so as to draw safer conclusions.