MAGEC2 is a sensitive and novel marker for seminoma: a tissue microarray analysis of 325 testicular germ cell tumors

Germ cell tumors in children

Pediatric germ cell tumors represent a rare but biologically diverse group of neoplasms arising from pluripotent primordial germ cells. The 2022 edition of the WHO Classification of Pediatric Tumors introduced the first organ independent classification of germ cell tumors, reflecting advances in molecular biology, histopathology, and clinical practice. This review highlights the key changes, including the refined distinctions between the different subtypes. These updates enhance diagnostic accuracy and provide a framework for understanding age-dependent differences in tumor biology and behavior. Emphasis is placed on integrating the new classification into multidisciplinary care, particularly in addressing diagnostic challenges in pre- and post-pubertal-type germ cell tumors. By bridging the gap between histopathology and oncology, the updated classification represents a pivotal step forward in improving outcomes for children with germ cell tumors.

Testicular Germ Cell Tumor Tissue Biomarker Analysis: A Comparison of Human Protein Atlas and Individual Testicular Germ Cell Tumor Component Immunohistochemistry

The accurate management of testicular germ cell tumors (TGCTs) depends on identifying the individual histological tumor components. Currently available data on protein expression in TGCTs are limited. The human protein atlas (HPA) is a comprehensive resource presenting the expression and localization of proteins across tissue types and diseases. In this study, we have compared the data from the HPA with our in-house immunohistochemistry on core TGCT diagnostic genes to test reliability and potential biomarker genes. We have compared the protein expression of 15 genes in TGCT patients and non-neoplastic testicles with the data from the HPA. Protein expression was converted into diagnostic positivity. Our study discovered discrepancies in three of the six core TGCT diagnostic genes, POU5F1, KIT and SOX17 in HPA. DPPA3, CALCA and TDGF1 were presented as potential novel TGCT biomarkers. MGMT was confirmed while RASSF1 and PRSS21 were identified as biomarkers of healthy testicular tissue. Finally, SALL4, SOX17, RASSF1 and PRSS21 dysregulation in the surrounding testicular tissue with complete preserved spermatogenesis of TGCT patients was detected, a potential early sign of neoplastic transformation. We highlight the importance of a multidisciplinary collaborative approach to fully understand the protein landscape of human testis and its pathologies.

Comprehensive characteristics of pathological subtypes in testicular germ cell tumor: Gene expression, mutation and alternative splicing

Background

Testicular germ cell tumor (TGCT) is the most common tumor in young men, but molecular signatures, especially the alternative splicing (AS) between its subtypes have not yet been explored.

Methods

To investigate the differences between TGCT subtypes, we comprehensively analyzed the data of gene expression, alternative splicing (AS), and somatic mutation in TGCT patients from the TCGA database. The gene ontology (GO) enrichment analyses were used to explore the function of differentially expressed genes and spliced genes respectively, and Spearman correlation analysis was performed to explore the correlation between differential genes and AS events. In addition, the possible patterns in which AS regulates gene expression were elaborated by the ensemble database transcript atlas. And, we identified important transcription factors that regulate gene expression and AS and functionally validated them in TGCT cell lines.

Results

We found significant differences between expression and AS in embryonal carcinoma and seminoma, while mixed cell tumors were in between. GO enrichment analyses revealed that both differentially expressed and spliced genes were enriched in transcriptional regulatory pathways, and obvious correlation between expression and AS events was determined. By analyzing the transcript map and the sites where splicing occurs, we have demonstrated that AS regulates gene expression in a variety of ways. We further identified two pivot AS-related molecules (SOX2 and HDAC9) involved in AS regulation, which were validated in embryonal carcinoma and seminoma cell lines. Differences in somatic mutations between subtypes are also of concern, with our results suggesting that mutations in some genes (B3GNT8, CAPN7, FAT4, GRK1, TACC2, and TRAM1L1) occur only in embryonal carcinoma, while mutations in KIT, KARS, and NRAS are observed only in seminoma.

Conclusions

In conclusion, our analysis revealed the differences in gene expression, AS and somatic mutation among TGCT subtypes, providing a molecular basis for clinical diagnosis and precise therapy of TGCT patients.

cfDNA methylation in liquid biopsies as potential testicular seminoma biomarker

Background: Seminoma is a testicular tumor type, routinely diagnosed after orchidectomy. As cfDNA represents a source of minimally invasive seminoma patient management, this study aimed to investigate whether cfDNA methylation of six genes from liquid biopsies, have potential as novel seminoma biomarkers. Materials & methods: cfDNA methylation from liquid biopsies was assessed by pyrosequencing and compared with healthy volunteers' samples. Results: Detailed analysis revealed specific CpGs as possible seminoma biomarkers, but receiver operating characteristic curve analysis showed modest diagnostic performance. In an analysis of panels of statistically significant CpGs, two DNA methylation panels emerged as potential seminoma screening panels, one in blood CpG8/CpG9/CpG10 (KITLG) and the other in seminal plasma CpG1(MAGEC2)/CpG1(OCT3/4). Conclusion: The presented data promote the development of liquid biopsy epigenetic biomarkers in the screening of seminoma patients.

Differential expression of preferentially expressed antigen in melanoma (PRAME) in testicular germ cell tumors - A comparative study with SOX17

The accurate identification of different components in testicular germ cell tumors (GCT) is essential for tailoring treatment and informing the clinical prognosis. PRAME (preferentially expressed antigen in melanoma), a member in the family of cancer testis antigens, plays critical roles in regulating pluripotency and suppressing somatic/germ cell differentiation in seminomas (SEM). To investigate the potential diagnostic value of PRAME in testicular GCT, here we comparatively examined the expression patterns of PRAME and SOX17 by immunohistochemistry in both pure and mixed GCT. Tissue microarrays constructed from 66 pure or mixed GCT were examined, including 25 seminomas (13 pure and 12 mixed), 35 embryonal carcinomas (EC; 7 pure and 28 mixed), 23 teratomas (TER; 10 pure and 13 mixed), 15 yolk sac tumors (YST; 1 pure and 14 mixed), and 5 choriocarcinomas (CC; 1 pure and 4 mixed), with 11 germ cell neoplasia in situ (GCNIS) and 6 normal testicular tissue as controls. The expression levels of PRAME or SOX17 were evaluated by a scoring system counting for intensity and extent of staining. PRAME nuclear expression was present in 92% (23/25) of SEM, including all 13 pure SEM, and 10 out of 12 seminomatous component of mixed GCT. In contrast, all EC and TER were completely negative for PRAME, and focal expression was demonstrated in 33.3% of YST and 20% of CC. As for SOX17, 96% of SEM and 73% of YST stained positively, whereas EC and CC were negative. Focal nuclear positivity was identified in the epithelial cell component of 17.4% (4/23) of TER. We found the sensitivity of PRAME to detect SEM to be comparable to SOX17, although SOX17 staining is more diffuse and stronger in the majority of cases. The specificity of PRAME for SEM appeared to be superior to that of SOX17 (92% versus 81%). In conclusion, PRAME is preferentially expressed in SEM or within the seminomatous component of mixed GCT with only focal variable expression in YST and CC, but shows no expression in EC and TER. These findings suggest that PRAME can be explored as a diagnostic marker for SEM.

CNV Hotspots in Testicular Seminoma Tissue and Seminal Plasma

Seminoma (SE) is the most frequent type of testicular tumour, affecting predominantly young men. Early detection and diagnosis of SE could significantly improve life quality and reproductive health after diagnosis and treatment. Copy number variation (CNV) has already been associated with various cancers as well as SE. In this study, we selected four genes (MAGEC2, NANOG, RASSF1A, and KITLG) for CNV analysis in genomic DNA (gDNA), which are located on chromosomes susceptible to gains, and whose aberrant expression was already detected in SE. Furthermore, CNV was analysed in cell-free DNA (cfDNA) from seminal plasma. Analysis was performed by droplet digital polymerase chain reaction (ddPCR) on gDNA from SE and nonmalignant testicular tissue. Seminal plasma cfDNA from SE patients before and after surgery was analysed, as well as from healthy volunteers. The CNV hotspot in gDNA from SE tissue was detected for the first time in all analysed genes, and for two genes, NANOG and KITLG it was reflected in cfDNA from seminal plasma. Although clinical value is yet to be determined, presented data emphasize a potential use of CNV as a potential SE biomarker from a liquid biopsy.

In Search of TGCT Biomarkers: A Comprehensive In Silico and Histopathological Analysis

Testicular germ cell tumors (TGCTs) are ever more affecting the young male population. Germ cell neoplasia in situ (GCNIS) is the origin of TGCTs, namely, seminomas (SE) and a heterogeneous group of nonseminomas (NS) comprising embryonal carcinoma, teratoma, yolk sac tumor, and choriocarcinoma. Response to the treatment and prognosis, especially of NS, depend on precise diagnosis with a necessity for discovery of new biomarkers. We aimed to perform comprehensive in silico analysis at the DNA, RNA, and protein levels of six prospective (HOXA9, MGMT, CFC1, PRSS21, RASSF1A, and MAGEC2) and six known TGCT biomarkers (OCT4, SOX17, SOX2, SALL4, NANOG, and KIT) and assess its congruence with histopathological analysis in all forms of TGCTs. Cancer Hallmarks Analytics Tool, the Search Tool for the Retrieval of Interacting Genes/Proteins database, and UALCAN, an interactive web resource for analyzing cancer OMICS data, were used. In 108 TGCT and 48 tumor-free testicular samples, the immunoreactivity score (IRS) was calculated. SE showed higher frequency in DNA alteration, while DNA methylation was significantly higher for all prospective biomarkers in NS. In GCNIS, we assessed the clinical positivity of RASSF1 and PRSS21 in 52% and 62% of samples, respectively, in contrast to low or nil positivity in healthy seminiferous tubules, TGTCs as a group, SE, NS, or all NS components. Although present in approximately 80% of healthy seminiferous tubules (HT) and GCNIS, HOXA9 was diagnostically positive in 64% of TGCTs, while it was positive in 82% of NS versus 29% of SE. Results at the DNA, mRNA, and protein levels on putative and already known biomarkers were included in the suggested panels that may prove to be important for better diagnostics of various forms of TGCTs.

HNF1β is a sensitive and specific novel marker for yolk sac tumor: a tissue microarray analysis of 601 testicular germ cell tumors

Hepatocyte Nuclear Factor 1 beta (HNF1β) is a transcription factor which plays an important role during early organogenesis, especially of the pancreato-biliary and urogenital tract. Furthermore, HNF1β is an established marker in the differential diagnosis of ovarian cancer and shows a distinct nuclear expression in the clear cell carcinoma subtype. Recently, it has been described in yolk sac tumor, which represents a common component in many non-seminomatous germ cell tumors. Due to its broad histologic diversity, the diagnosis may be challenging and additional tools are very helpful in the workup of germ cell tumors. Immunohistochemistry was used to study HNF1β expression in a tissue microarray (TMA) of 601 testicular germ cell tumors including seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, teratoma, germ cell neoplasia in situ (GCNIS), and normal tissue. The expression pattern was compared to glypican 3 (GPC3) and α-fetoprotein (AFP), two markers currently in use for the detection of yolk sac tumor. HNF1β showed a distinct nuclear staining in comparison to the cytoplasmic pattern of GPC3 and AFP. The sensitivity and specificity of HNF1β were 85.4% and 96.5%, of GPC3 83.3% and 90.7%, of AFP 62.5% and 97.7%. We conclude that HNF1β allows a reliable distinction of yolk sac tumor from other germ cell tumor components. Therefore, we propose HNF1β as a novel and robust marker in the immunohistochemical workup of testicular germ cell tumors.

True hermaphroditism with seminoma: A case report

The aim of the present study was to discuss the diagnosis and treatment of a patient with true hermaphroditism complicated by seminoma. The patient was a 35-year-old man who was admitted to the Peking University Shenzhen Hospital with a retractable mass in the left inguinal region for 20 years. A computed tomography examination revealed right cryptorchidism. The postoperative pathology suggested true hermaphroditism with a seminoma. The results of immunohistochemical examination were as follows: Sal-like protein 4+ (partially weak); octamer-binding transcription factor 4+ (partially weak); CD117+; cytokeratin+; CD30-, α-fetoprotein-, inhibin-α-. The karyotype was 46, XY. Adult true hermaphroditism combined with seminoma is rare in clinical practice. Combined histopathological analysis, immunophenotype detection and karyotype analysis are of great value in the diagnosis and differential diagnosis. Early intervention and combined surgery with radiotherapy and chemotherapy can significantly improve the prognosis of such patients.

Deep exploration of the immune infiltrate and outcome prediction in testicular cancer by quantitative multiplexed immunohistochemistry and gene expression profiling

Platinum-based chemotherapy is usually curative for patients with testicular germ cell tumors (TGCT), but a subset of patients experience disease progression and poor clinical outcomes. Here, we tested whether immune profiling of TGCT could identify novel prognostic markers and therapeutic targets for this patient cohort. We obtained primary and metastatic TGCT samples from one center. We performed immune profiling using multiplexed fluorescence immunohistochemistry (FIHC) for T-cell subsets and immune checkpoints, and targeted gene expression profiling (Nanostring nCounter Immune panel). Publically available data sets were used to validate primary sample analyses. Nearly all samples had some degree of T-cell infiltration and immune checkpoint expression. Seminomas were associated with increased CD3⁺ T-cell infiltration, decreased Regulatory T-cells, increased PD-L1, and increased PD-1/PD-L1 spatial interaction compared with non-seminomas using FIHC. Gene expression profiling confirmed these findings and also demonstrated increased expression of T-cell markers (e.g., IFNγ, and LAG3) and cancer/testis antigens (e.g., PRAME) in seminomas, whereas non-seminomas demonstrated high neutrophil and macrophage gene signatures. Irrespective of histology, advanced TGCT stage was associated with decreased T-cell and NK-cell signatures, while Treg, neutrophil, mast cell and macrophage signatures increased with advanced stage. Importantly, cancer/testis antigen, neutrophil, and CD8⁺/regulatory T-cell signatures correlated with recurrence free survival. Thus, deep immune characterization of TGCT using IHC and gene expression profiling identified activated T-cell infiltration which correlated with seminoma histology and good prognosis. These results may provide a rationale for testing of anti-PD-1/PD-L1 agents and suggest prognostic markers.

Potential application and prevalence of the CD30 (Ki-1) antigen among solid tumors: A focus review of the literature

BACKGROUND

CD30 (Ki-1) is a cell membrane protein derived from the tumor necrosis factor (TNF) receptor family. The CD30 antigen has been associated primarily with Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (sALCL). Brentuximab vedotin (BV) is an antibody-drug conjugate targeting the CD30 antigen. FDA approval for BV includes relapsed and refractory HL and sALCL. The CD30 antigen also has been identified in many solid tumors, predominantly of germ cell origins and early clinical data is promising.

OBJECTIVE

Perform a focus literature review evaluating the prevalence of the CD30 antigen among nonlymphomatous tumors with a potential correlate for CD30 targeted therapy.

ELIGIBILITY CRITERIA

Inclusion criteria: all retrospective reviews and case reports citing CD30 positivity or negativity in non-lymphomatous malignancies in which data were presented based on location.

EXCLUSION CRITERIA

studies with hematopoetic malignancies, cutaneous malignancies, non-human populations, and non-english publications.

INCLUDED STUDIES

A total of 119 articles met these criteria and are summarized in this manuscript.

CONCLUSION

The CD30 antigen has shown variable prevalence among non-hematopoetic tumors, most notably among germ cell tumors and mesothelioma. With additional, preclinical and properly powered clinical studies, CD30 targeted therapy such as that of BV, alone or in combination with other agents may prove to be a strong candidate in the treatment of various CD30⁺ malignancies.

Brentuximab vedotin for treatment of non-Hodgkin lymphomas: A systematic review

BACKGROUND

Brentuximab vedotin (BV) is an antibody-drug conjucate (ADC) comprising a CD30-directed antibody, conjugated to the microtubule-disrupting agent MMAE via a protease cleavable linker. BV is FDA approved for use in relapsed classical Hodgkin lymphoma (HL) and relapsed systemic anaplastic large cell lymphoma (sALCL). There are multiple publications for its utility in other malignancies such as diffuse large B-cell lymphoma (DLBCL), mycosis fungoides (MF), Sézary syndrome (SS), T-cell lymphomas (TCL), primary mediastinal lymphoma (PMBL), and post-transplant lymphoproliferative disorders (PTLD). We believe that BV could potentially provide a strong additional treatment option for patients suffering from NHL.

OBJECTIVE

Perform a systematic review on the use of BV in non-Hodgkin lymphoma (NHL) and other CD30⁺ malignancies in humans.

DATA SOURCES

We searched various databases including PubMed (1946-2015), EMBASE (1947-2015), and Cochrane Central Register of Controlled Trials (1898-2015).

ELIGIBILITY CRITERIA

Inclusion criteria specified all studies and case reports of NHLs in which BV therapy was administered.

INCLUDED STUDIES

A total of 28 articles met these criteria and are summarized in this manuscript.

CONCLUSION

Our findings indicate that BV induces a variety of responses, largely positive in nature and variable between NHL subtypes. With additional, properly powered prospective studies, BV may prove to be a strong candidate in the treatment of various CD30⁺ malignancies.

Pilot Study on MAGE-C2 as a Potential Biomarker for Triple-Negative Breast Cancer

Objective. In the current study, we measured the expression status of melanoma antigen gene c2 (MAGE-C2) in triple-negative breast cancer (TNBC) and analyzed its prognostic with the clinical pathological features of patients with TNBC. Methods. The expressions statuses of MAGE-C2 were detected in TNBC tissues and paracarcinoma tissues by immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR), and western blotting. Then, we investigated the relationship of MAGE-C2 expression status and clinicopathological parameters of TNBC patients by the chi-squared test. Finally, we discussed the relations of MAGE-C2 expression state and prognosis of patients with TNBC by Kaplan-Meier method and Cox proportional hazards model. Results. High MAGE-C2 expression was found in 38.18% (42/110) of TNBC tissues. In adjacent tissues it was 9.09% (10/110). High MAGE-C2 expression in TNBC patients was closely associated with lymph node status, tumor node metastasis (TNM) stage, and lymphovascular invasion (P < 0.001). TNBC patients with high MAGE-C2 expression had significantly shorter survival time than low expression patients. We also found that age, lymph node status, TNM stage, lymphovascular invasion, and MAGE-C2 expression status were closely associated with overall survival of TNBC patients (P < 0.05). Conclusion. High MAGE-C2 expression may serve as an independent prognostic factor for TNBC patients.

Frequent PD-L1 expression in testicular germ cell tumors

BACKGROUND

Many testicular germ cell cancers are curable despite metastatic disease, but about 10-15% of patients fail cisplatin-based first-line treatment. Immunotherapy is considered as additional treatment approach for these patients. Inhibition of the interaction between Programmed Death Receptor 1 (PD-1) and Programmed Death Receptor Ligand 1 (PD-L1) enhances T-cell responses in vitro and mediates clinical antitumour activity. We analysed the expression of PD-L1 in testicular germ cell tumours to evaluate its potential as target for immunotherapeutic strategies.

METHODS

Immunohistochemistry was performed in 479 formalin-fixed paraffin-embedded specimens using a rabbit monoclonal antibody (E1L3N). The tissue microarray consisted of 208 pure seminomas, 121 non-seminomas, 20 intratubular germ cell neoplasia unclassified (IGCNU) and 20 specimens of non-neoplastic testicular tissue.

RESULTS

Programmed Death Receptor Ligand-1 expression was found in 73% of all seminomas and in 64% of all non-seminomas. None of 20 IGCNU and none of 20 normal tissue specimens exhibited PD-L1 expression. PD-L1 positive stromal cells were only detected in seminomas, but not in non-seminomas. The anti PD-L1 antibody showed a pre-dominantly membranous staining pattern in testicular tumour cells, as well as expression in stromal cells.

CONCLUSIONS

This frequent expression of PD-L1 in human testicular germ cell tumours suggests that patients with testicular germ cell tumours could profit from immunotherapeutic strategies using anti-PD1 and anti-PDL1 antibodies.

Primary mediastinal seminomas: a comprehensive immunohistochemical study with a focus on novel markers

Primary mediastinal seminomas are unusual tumors that can present in a pure form or as part of a mixed germ cell tumor. Contrary to testicular seminomas, little is known about the expression of novel immunohistochemical markers in mediastinal seminomas. This study investigates the immunohistochemical features of these tumors with a focus on novel markers. Thirty-two cases of primary mediastinal seminomas were reviewed; and representative whole-tissue sections were selected for immunohistochemical studies using antibodies directed against high molecular weight cytokeratin 5/6 (CK5/6), low molecular weight cytokeratin (CAM5.2), octamer-binding transcription factor 3/4 (OCT3/4), spalt-like transcription factor 4 (SALL4), GATA binding protein 3 (GATA-3), sry-related HMG box 2 (SOX2), SOX17, human T cell leukemia/lymphoma 1 (TCL1), glypican 3, melanoma associated antigen C2 (MAGEC2), and paired box gene 8 (Pax8). The percentage of positive tumor cells as well as the intensity of staining was evaluated and scored. Thirty-one cases (97%) expressed SOX17, whereas 29 cases (91%) were positive for OCT3/4 and SALL4, respectively. Twenty-eight cases (88%) expressed MAGEC2 and CAM5.2, respectively. Two cases (6%) were positive for Pax8, and a single case (3%) was positive for TCL1. None of the cases stained with CK5/6, GATA-3, SOX2, or glypican 3. Similar to testicular seminomas, mediastinal seminomas show consistent expression of OCT3/4, SALL4, SOX17, and MAGEC2 and are negative for SOX2, glypican 3, GATA-3, and CK5/6. Pax8 positivity is only inconsistently identified in mediastinal seminomas. Contrary to their testicular counterparts, mediastinal tumors show diffuse expression of low-molecular-weight cytokeratin in up to 90% of cases and are commonly negative for TCL1. Although there is some immunohistochemical overlap between testicular and mediastinal seminomas, considerable differences also exist and should be acknowledged when dealing with these tumors.

An oncofetal and developmental perspective on testicular germ cell cancer

Germ cell tumors (GCTs) represent a diverse group of tumors presumably originating from (early fetal) developing germ cells. Most frequent are the testicular germ cell cancers (TGCC). Overall, TGCC is the most frequent malignancy in Caucasian males (20-40 years) and remains an important cause of (treatment related) mortality in these young men. The strong association between the phenotype of TGCC stem cell components and their totipotent ancestor (fetal primordial germ cell or gonocyte) makes these tumors highly relevant from an onco-fetal point of view. This review subsequently discusses the evidence for the early embryonic origin of TGCCs, followed by an overview of the crucial association between TGCC pathogenesis, genetics, environmental exposure and the (fetal) testicular micro-environment (genvironment). This culminates in an evaluation of three genvironmentally modulated hallmarks of TGCC directly related to the oncofetal pathogenesis of TGCC: (1) maintenance of pluripotency, (2) cell cycle control/cisplatin sensitivity and (3) regulation of proliferation/migration/apoptosis by KIT-KITL mediated receptor tyrosine kinase signaling. Briefly, TGCC exhibit identifiable stem cell components (seminoma and embryonal carcinoma) and progenitors that show large and consistent similarities to primordial/embryonic germ cells, their presumed totipotent cells of origin. TGCC pathogenesis depends crucially on a complex interaction of genetic and (micro-)environmental, i.e. genvironmental risk factors that have only been partly elucidated despite significant effort. TGCC stem cell components also show a high degree of similarity with embryonic stem/germ cells (ES) in the regulation of pluripotency and cell cycle control, directly related to their exquisite sensitivity to DNA damaging agents (e.g. cisplatin). Of note, (ES specific) micro-RNAs play a pivotal role in the crossover between cell cycle control, pluripotency and chemosensitivity. Moreover, multiple consistent observations reported TGCC to be associated with KIT-KITL mediated receptor tyrosine kinase signaling, a pathway crucially implicated in proliferation, migration and survival during embryogenesis including germ cell development. In conclusion, TGCCs are a fascinating model for onco-fetal developmental processes especially with regard to studying cell cycle control, pluripotency maintenance and KIT-KITL signaling. The knowledge presented here contributes to better understanding of the molecular characteristics of TGCC pathogenesis, translating to identification of at risk individuals and enhanced quality of care for TGCC patients (diagnosis, treatment and follow-up).

Cancer testis antigen expression in testicular germ cell tumorigenesis

Cancer testis antigens are encoded by germ line-associated genes that are present in normal germ cells of testis and ovary but not in differentiated tissues. Their expression in various human cancer types has been interpreted as 're-expression' or as intratumoral progenitor cell signature. Cancer testis antigen expression patterns have not yet been studied in germ cell tumorigenesis with specific emphasis on intratubular germ cell neoplasia unclassified as a precursor lesion for testicular germ cell tumors. Immunohistochemistry was used to study MAGEA3, MAGEA4, MAGEC1, GAGE1 and CTAG1B expression in 325 primary testicular germ cell tumors, including 94 mixed germ cell tumors. Seminomatous and non-seminomatous components were separately arranged and evaluated on tissue microarrays. Spermatogonia in the normal testis were positive, whereas intratubular germ cell neoplasia unclassified was negative for all five CT antigens. Cancer testis antigen expression was only found in 3% (CTAG1B), 10% (GAGE1, MAGEA4), 33% (MAGEA3) and 40% (MAGEC1) of classic seminoma but not in non-seminomatous testicular germ cell tumors. In contrast, all spermatocytic seminomas were positive for cancer testis antigens. These data are consistent with a different cell origin in spermatocytic seminoma compared with classic seminoma and support a progression model with loss of cancer testis antigens in early tumorigenesis of testicular germ cell tumors and later re-expression in a subset of seminomas.

[Testicular seminomas. The classical and the less classical ones]

Testicular germ cell tumors are generally rare but represent the most common solid neoplasms in young men. They are subdivided into seminomas and non-seminomatous germ cell tumors. Usually the diagnosis of a seminoma is straightforward due to the characteristic morphology, although problems in differential diagnosis can occur because of unusual histological growth patterns. This article describes the challenging differential diagnosis with respect to seminomas versus non-seminomatous germ cell tumors, sex cord stromal tumors, lymphomas and non-neoplastic conditions, such as scars and inflammatory changes. In addition, prognostic factors for seminomas are presented and discussed.

MAGEC2, an epithelial-mesenchymal transition inducer, is associated with breast cancer metastasis

MAGEC2 is a member of melanoma antigen (MAGE) family of cancer-testis antigens and associated with tumor relapse and metastasis. Here, we investigated the expression of MAGEC2 in patients with breast cancer and its clinical effects with underlying mechanisms. The expression levels of MAGEC2 were compared between 420 invasive ductal carcinoma (IDC) and 120 ductal carcinoma in situ of the breast. Correlations between MAGEC2 expression and clinico-pathologic factors or survival of patients with IDC were analyzed. In addition, MAGEC2 expression levels in tumor tissues dissected from the primary focus and matched tumor-invaded axillary lymph nodes were analyzed in 8 breast cancer patients. The functional effects of MAGEC2 overexpression were assessed in vitro using scratch assay and transwell chamber assay. MAGEC2 expression was increased in metastatic breast cancer in comparison to the non-metastatic. MAGEC2 expression was significantly associated with ER negative expression (P = 0.037), high tumor grade (P = 0.014) and stage (P = 0.002), high incidence of axillary lymph node metastasis (P = 0.013), and distant metastasis (P = 0.004). Patients with tumor with MAGEC2 positive expression have a worse prognosis and a shorter metastasis free interval. Multivariate analyses showed that MAGEC2 expression was an independent risk factor for patient overall survival and metastasis-free survival. Breast cancer cells that overexpressed MAGEC2 had stronger migratory and invasive potential than control-treated cells. Epithelial markers (E-cadherin and cytokeratin) were down-regulated in MAGEC2-overexpressing cells compared to controls, whereas mesenchymal markers (vimentin and fibronectin) were upregulated. Our results indicate that MAGEC2 has a role in breast cancer metastasis through inducing epithelial-mesenchymal transition. In addition, MAGEC2 is a novel independent poor prognostic factor in patients with IDC. Thus, targeting MAGEC2 may provide a novel therapeutic strategy for breast cancer treatment.

High endothelial venule-like vessels and lymphocyte recruitment in testicular seminoma

Seminoma, the most common testicular malignant neoplasm, originates from germ cells and is characterized by the presence of numerous tumour-infiltrating lymphocytes (TILs). Although it is widely accepted that TILs function in surveillance and cytotoxicity in various tumours including seminoma, detailed mechanisms governing TIL recruitment are not fully understood. It has been shown that high endothelial venule (HEV)-like vessels are induced in inflamed and neoplastic tissues and contribute to lymphocyte recruitment in a manner similar to the way physiological lymphocyte homing occurs in secondary lymphoid organs. Here, we report that HEV-like vessels, which express MECA-79(+) 6-sulfo sialyl Lewis X-capped structures, are induced in TIL aggregates in seminoma, and that such vessels potentially recruit circulating lymphocytes, as an E-selectin•IgM chimera bound these vessels in a calcium-dependent manner. These HEV-like vessels express intercellular adhesion molecule 1 (ICAM-1), but not vascular cell adhesion molecule 1 (VCAM-1) or mucosal addressin cell adhesion molecule 1 (MAdCAM-1), which likely contributes to lymphocyte firm attachment. We also found that the number of T cells attached to the luminal surface of HEV-like vessels was greater than the number of B cells (p < 0.0001). Interestingly, while CD8(+) cytotoxic T lymphocytes (CTLs) attached to the lumen of HEV-like vessels were scarcely detected, significant numbers of proliferative CTLs were observed outside vessels. These histological findings strongly suggest that TILs, particularly T cells, are recruited to seminoma tissues via HEV-like vessels, and that tumour-infiltrating CTLs then undergo proliferation after transmigration through HEV-like vessels in testicular seminoma.

Testicular germ cell tumors: biology and clinical update

PURPOSE OF REVIEW

This overview discusses several important developments in testicular germ cell tumors in the past year.

RECENT FINDINGS

Genomic studies continue to investigate gene expression as possible markers for disease relapse and chemotherapy resistance. Optimal treatment strategies for early-stage seminomas are evolving toward surveillance versus chemotherapy and away from radiation, and the role of retroperitoneal lymph node dissection in disseminated nonseminomatous cancers in complete remission is becoming less certain.

SUMMARY

Treatment and surveillance paradigms continue to be defined and refined for both early and late-stage disease as research in these areas continues and the data from multiple large studies mature.