Chromosomes, genes, and development of testicular germ cell tumors

Cryptorchidism and testicular cancer in the dog: unresolved questions and challenges in translating insights from human studies†

Cryptorchidism, the failure of one or both testes to descend into the scrotum, and testicular cancer show a strong correlation in both dogs and humans. Yet, long-standing medical debates persist about whether the location of undescended testes directly causes testicular cancer in humans or if both conditions stem from a common origin. Although testicular cancer is a prevalent disease in dogs, even less is known about its cause and correlation with testicular descent in this species. This review investigates the relation between these two disorders in dogs, drawing insights from human studies, and examines key biomarkers identified thus far. In addition, it explores potential causal links, including the impact of temperature on maturing testicular cells and a potential shared genetic origin. Notably, this literature review reveals significant differences between men and dogs in reproductive development, histological and molecular features of testicular tumors, and the prevalence of specific tumor types, such as Sertoli cell tumors in cryptorchid dogs and germ cell tumors in humans. These disparities caution against using dogs as models for human testicular cancer research and underscore the limitations when drawing comparisons between species. The paper concludes by suggesting specific research initiatives to enhance our understanding of the complex interplay between cryptorchidism and testicular cancer in dogs.

Epigenetic Regulation of Driver Genes in Testicular Tumorigenesis

In testicular germ cell tumor type II (TGCT), a seminoma subtype expresses an induced pluripotent stem cell (iPSC) panel with four upregulated genes, OCT4/POU5F1, SOX17, KLF4, and MYC, and embryonal carcinoma (EC) has four upregulated genes, OCT4/POU5F1, SOX2, LIN28, and NANOG. The EC panel can reprogram cells into iPSC, and both iPSC and EC can differentiate into teratoma. This review summarizes the literature on epigenetic regulation of the genes. Epigenetic mechanisms, such as methylations of cytosines on the DNA string and methylations and acetylations of histone 3 lysines, regulate expression of these driver genes between the TGCT subtypes. In TGCT, the driver genes contribute to well-known clinical characteristics and the driver genes are also important for aggressive subtypes of many other malignancies. In conclusion, epigenetic regulation of the driver genes are important for TGCT and for oncology in general.

Identification and Prognostic Value Exploration of Radiotherapy Sensitivity-Associated Genes in Non-Small-Cell Lung Cancer

Background

Non-small-cell lung cancer (NSCLC) is a prevalent malignancy with high mortality and poor prognosis. The radiotherapy is one of the most common treatments of NSCLC, and the radiotherapy sensitivity of patients could affect the individual prognosis of NSCLC. However, the prognostic signatures related to radiotherapy response still remain limited. Here, we explored the radiosensitivity-associated genes and constructed the prognostically predictive model of NSCLC cases.

Methods

The NSCLC samples with radiotherapy records were obtained from The Cancer Genome Atlas database, and the mRNA expression profiles of NSCLC patients from the GSE30219 and GSE31210 datasets were obtained from the Gene Expression Omnibus database. The Weighted Gene Coexpression Network Analysis (WGCNA), univariate, least absolute shrinkage and selection operator (LASSO), multivariate Cox regression analysis, and nomogram were conducted to identify and validate the radiotherapy sensitivity-related signature.

Results

WGCNA revealed that 365 genes were significantly correlated with radiotherapy response. LASSO Cox regression analysis identified 8 genes, including FOLR3, SLC6A11, ALPP, IGFN1, KCNJ12, RPS4XP22, HIST1H2BH, and BLACAT1. The overall survival (OS) of the low-risk group was better than that of the high-risk group separated by the Risk Score based on these 8 genes for the NSCLC patients. Furthermore, the immune infiltration analysis showed that monocytes and activated memory CD4 T cells had different relative proportions in the low-risk group compared with the high-risk group. The Risk Score was correlated with immune checkpoints, including CTLA4, PDL1, LAG3, and TIGIT.

Conclusion

We identified 365 genes potentially correlated with the radiotherapy response of NSCLC patients. The Risk Score model based on the identified 8 genes can predict the prognosis of NSCLC patients.

Cisplatin Cytotoxicity in Human Testicular Germ Cell Tumor Cell Lines Is Enhanced by the CDK4/6 Inhibitor Palbociclib

BACKGROUND

Cisplatin-based chemotherapy is the mainstay of pharmacological treatment of testicular germ cell tumors (TGCTs) that, together with early diagnosis, surgery, and/or radiotherapy, has dramatically improved the prognosis. However, under the pressure of such pharmacological therapy (both classical cytotoxic drugs and targeted therapy), cancer cells may develop resistance. Thus, combination therapy that may include cytotoxic drugs and targeted therapy could offer an advantage to curing cancers. Here, we investigated the in vitro and in vivo antitumor activity of cisplatin, as a single-agent or in combination with palbociclib.

PATIENTS AND METHODS

The cell viability of Ntera-2/cl.D1 (NT2/D1) and 833K after exposure to palbociclib and/or cisplatin was evaluated by MTT dye reduction assay and by ATPLite Luminescence Assay. Gene and protein expression was evaluated by quantitative reverse transcription polymerase chain reaction and by western blot. Flow cytometric cell-cycle analysis was performed, as well. The in vivo experiments were conducted on NT2/D1 xenografts in AB zebrafish embryos exposed to the drugs.

RESULTS

Palbociclib and cisplatin decreased TGCT cell viability both in vitro and in vivo. This effect was additive when cells were exposed to the drug combination. In the NT2/D1 cell lines, the drug combination also exerted a positive effect with regard to delaying cell recovery after the toxic insult. In the combination experiments, cisplatin-induced cell accumulation in G2/M was predominant compared with the palbociclib effect.

CONCLUSIONS

These results could provide the rationale for developing further studies to improve the pharmacological treatment of TGCTs, but they must be demonstrated in a dedicated clinical trial.

Testicular germ cell tumors type 2 have high RNA expression of LDHB, the gene for lactate dehydrogenase subunit B

This study analyzed RNA expression of genes for three serum tumor markers, alpha fetoprotein (AFP), human chorionic gonadotropin (hCG), and lactate dehydrogenase (LDH), in patients with testicular germ cell tumors (TGCT) type 2. The gene AFP encodes AFP, the gene for chorionic gonadotropin beta polypeptide 5 (CGB5) encodes a major part of the specific beta subunit of hCG, and the genes for LDH subunit A (LDHA), LDH subunit B (LDHB), and LDH subunit C (LDHC) encode three different subunits of LDH. LDHB encodes the LDHB subunit present as a tetramer in LDH isoenzyme 1 (LDH-1). We examined three datasets with 203 samples of normal testis tissue (NT) and TGCT type 2. Yolk sac tumor (YST) expressed RNA of AFP fourteen thousand times higher than seminoma (SE), embryonal carcinoma (EC), and teratoma (TER) combined (P = 0.00015). In the second microarray, choriocarcinoma (CC) expressed RNA of CGB5 ten times higher than other histologic types of TGCT combined. EC expressed RNA of LDHB twice higher than SE, YST and TER combined (P = 0.000041). EC expressed RNA of LDHB higher than that YST expressed RNA of AFP and that CC expressed RNA of CGB5. In conclusion, TGCT type 2 expressed RNA of LDHB markedly higher than the RNA of 23 other candidate genes for TGCT type 2.

Meta-Analysis of Gene Expressions in Testicular Germ Cell Tumor Histologies

There is no consensus as to how a precursor lesion, germ cell neoplasia in situ (GCNIS), develops into the histologic types of testicular germ cell tumor type II (TGCT). The present meta-analysis examined RNA expressions of 24 candidate genes in three datasets. They included 203 samples of normal testis (NT) and histologic types of TGCT. The Fisher’s test for combined p values was used for meta-analysis of the RNA expressions in the three datasets. The histologic types differed in RNA expression of PRAME, KIT, SOX17, NANOG, KLF4, POU5F1, RB1, DNMT3B, and LIN28A (p < 0.01). The histologic types had concordant differences in RNA expression of the genes in the three datasets. Eight genes had overlap with a high RNA expression in at least two histologic types. In contrast, only seminoma (SE) had a high RNA expression of KLF4 and only embryonal carcinoma (EC) had a high RNA expression of DNMT3B. In conclusion, the meta-analysis showed that the development of the histologic types of TGCT was driven by changes in RNA expression of candidate genes. According to the RNA expressions of the ten genes, TGCT develops from NT over GCNIS, SE, EC, to the differentiated types of TGCT.

The expression signature of cancer-associated KRAB-ZNF factors identified in TCGA pan-cancer transcriptomic data

The KRAB-ZNF (Krüppel-associated box domain zinc finger) gene family is composed of a large number of highly homologous genes, gene isoforms, and pseudogenes. The proteins encoded by these genes, whose expression is often tissue-specific, act as epigenetic suppressors contributing to the addition of repressive chromatin marks and DNA methylation. Due to its high complexity, the KRAB-ZNF family has not been studied in sufficient detail, and the involvement of its members in carcinogenesis remains mostly unexplored. In this study, we aimed to provide a comprehensive description of cancer-associated KRAB-ZNFs using publicly available The Cancer Genome Atlas pan-cancer datasets. We analyzed 6727 tumor and normal tissue samples from 16 cancer types. Here, we showed that a small but distinctive cluster of 16 KRAB-ZNFs is commonly upregulated across multiple cancer cohorts in comparison to normal samples. We confirmed these observations in the independent panels of lung and breast cancer cell lines and tissues. This upregulation was also observed for most of the KRAB-ZNF splicing variants, whose expression is simultaneously upregulated in tumors compared to normal tissues. Finally, by analyzing the clinicopathological data for breast and lung cancers, we demonstrated that the expression of cancer-associated KRAB-ZNFs correlates with patient survival, tumor histology, and molecular subtyping. Altogether, our study allowed the identification and characterization of KRAB-ZNF factors that may have an essential function in cancer biology and thus potential to become novel oncologic biomarkers and treatment targets.

miR‑199a‑3p/Sp1/LDHA axis controls aerobic glycolysis in testicular tumor cells

Aerobic glycolysis is one of the characteristics of tumor metabolism and contributes to the development of tumors. Studies have identified that microRNA (miRNA/miR) serves an important role in glucose metabolism of tumors. miR‑199a‑3p is a member of the miR‑199a family that controls the outcomes of cell survival and death processes, and previous studies have indicated that the expression of miR‑199a‑3p is low and may be an inhibitor in several cancer types, including testicular tumors. The present study discussed the role and underlying mechanism of miR‑199a‑3p in aerobic glycolysis of Ntera‑2 cells and identified its downstream factors. Firstly, miR‑199a‑3p exhibited an inhibitory effect on lactic acid production, glucose intake, and reactive oxygen species (ROS) and adenosine 5'‑triphosphate (ATP) levels in Ntera‑2 cells. Then, using bioinformatics, recombinant construction and a dual luciferase reporter gene system, transcription factor Specificity protein 1 (Sp1) was determined as the direct target of miR‑199a‑3p. Also, downregulation of Sp1 by RNA interference decreased lactic acid production, glucose intake, and ROS and ATP levels in Ntera‑2 cells. Subsequently, through a functional rescue experiment, it was identified that the overexpression of Sp1 may abate the inhibition of miR‑199a‑3p on glucose metabolism, with the exception of ATP level, suggesting a reciprocal association between Sp1 and miR‑199a‑3p. Finally, it was determined that miR‑199a‑3p overexpression and Sp1 knockdown decreased lactate dehydrogenase A (LDHA) protein expression, which indicated that LDHA is a downstream target of the miR‑199a‑3p/Sp1 signaling pathway. To additionally verify the regulation of LDHA expression by 199a‑3p/Sp1, a LDHA promoter reporter plasmid was generated and the high activity of the promoter, which contained 3 potential Sp1 binding elements, was confirmed. In addition, the overexpression of Sp1 led to the increased activity of the LDHA promoter, whereas knockdown of Sp1 exhibited the opposite effect. Therefore, the results of the present study demonstrated that miR‑199a‑3p can inhibit LDHA expression by downregulating Sp1, and provided mechanistic evidence supporting the existence of a novel miR‑199a‑3p/Sp1/LDHA axis and its critical contribution to aerobic glycolysis in testicular cancer cells.

Differences in DNA methylation profiles by histologic subtype of paediatric germ cell tumours: a report from the Children's Oncology Group

BACKGROUND

Abnormal DNA methylation may be important in germ cell tumour (GCT) aetiology, as germ cells undergo complete epigenetic reprogramming during development. GCTs show differences in global and promoter methylation patterns by histologic subtype. We conducted an epigenome-wide study to identify methylation differences by GCT histology.

METHODS

Using the Illumina HumanMethylation450K array we measured methylation in 154 paediatric GCTs (21 germinomas/seminomas/dysgerminoma, 70 yolk sac tumours [YST], 9 teratomas, and 54 mixed histology tumours). We identified differentially methylated regions (DMRs) between GCT histologies by comparing methylation beta values.

RESULTS

We identified 8,481 DMRs (FWER < 0.05). Unsupervised hierarchical clustering of individual probes within DMRs resulted in four high level clusters closely corresponding to tumour histology. Clusters corresponding to age, location, sex and FFPE status were not observed within these DMRs. Germinomas displayed lower levels of methylation across the DMRs relative to the other histologic subtypes. Pathway analysis on the top 10% of genes with differential methylation in germinomas/seminomas/dysgerminoma compared to YST suggested angiogenesis and immune cell-related pathways displayed decreased methylation in germinomas/seminomas/dysgerminoma relative to YST.

CONCLUSIONS

Paediatric GCT histologies have differential methylation patterns. The genes that are differentially methylated may provide insights into GCT aetiology including the timing of GCT initiation.

A 4-month-old boy with gastrointestinal stromal tumor of mesocolon

Gastrointestinal stromal tumors (GISTs) are very uncommon in pediatric patients, and they are distinct clinical-pathological and molecular deviations from their adult counterparts. Most pediatric GISTs lack the c-kit or platelet-derived growth factor receptor alpha (PDGFRA) genes mutations. To date, there is no published standard guidelines available for the best treatment of pediatric GISTs, especially for infant GIST. Therefore, we report a case of 4-month-old infant with GIST of mesocolon without KIT/PDGFRA mutation. We also review the clinical, biological, and genetic features of pediatric GISTs and re-think several questions that could affect clinical practice.

Frequency and Markers of Precursor Lesions and Implications for the Pathogenesis of Testicular Germ Cell Tumors

BACKGROUND

The World Health Organization classification of urologic cancer 2016 describes 3 noninvasive precursor lesions for testicular germ cell tumor type II (TGCT) of young adults. Germ cell neoplasia in situ is the initial precursor lesion. Intratubular seminoma (ITSE), and intratubular embryonal carcinoma (ITEC) are 2 intermediate precursor lesions. Microinvasive testicular germ cell tumor (MGCT) is an invasive precursor lesion.

MATERIALS AND METHODS

We undertook a retrospective study of testes obtained using orchiectomy for TGCT and examined precursor lesions. The examinations included immunohistochemical staining of the precursor lesions for octamer-binding transcription factor 4 (OCT4), CD117, and CD30. We examined 63 consecutive and evaluable patients.

RESULTS

Of the patients, 44 had seminoma and 19 had a nonseminomatous TGCT. MGCT was more frequent than ITSE (P = .002; χ2 test). None of the testes had ITEC. Immunohistochemistry showed that 72 of 77 precursor lesions (93%) stained positive for OCT4 and CD117 and negative for CD30. The pattern represents a seminomatous immunophenotype. A meta-analysis of the published studies regarding precursor lesions included 1007 patients. Overall, the pooled rate of ITSE was 29% (95% confidence interval [CI], 18%-40%) and the pooled rate of MGCT was 21% (95% CI, 15%-27%).

CONCLUSION

MGCT is a frequent intermediate precursor lesion.

Molecular characterization of metastatic exon 11 mutant gastrointestinal stromal tumors (GIST) beyond KIT/PDGFRα genotype evaluated by next generation sequencing (NGS)

About 85% of GISTs are associated with KIT and PDGFRα gene mutations, which predict response to tyrosine kinase inhibitors. Although the outcomes in patients affected by GIST have dramatically improved, tumor progression control still remains a challenge. The aim of this study is the genomic characterization of individual metastatic KIT-exon 11-mutant GIST to identify additional aberrations and simultaneous molecular events representing potential therapeutic targets.Seven patients with metastatic GIST were studied with whole transcriptome sequencing and copy number analysis. Somatic single nucleotide variations were called; however, no shared mutated genes were detected except KIT. Almost all patients showed loss of genomic regions containing tumor suppressor genes, sometimes coupled with single nucleotide mutation of the other allele. Additionally, six fusion transcripts were found and three patients showed amplifications involving known oncogenes.Evaluating the concordance between CN status and mRNA expression levels, we detected overexpression of CCND2 and EGFR and silencing of CDKN2A, CDKN2C, SMARCB1, PTEN and DMD. Altered expression of these genes could be responsible for aberrant activation of signaling pathways that support tumor growth. In this work, we assessed the effect of Hedgehog pathway inhibition in GIST882 cells, which causes decrement of cell viability associated with reduction of KIT expression.Additional genomic alterations not previously reported in GIST were found even if not shared by all samples. This contributes to a more detailed molecular understanding of this disease, useful for identification of new targets and novel therapeutics and representing a possible point of departure for a truly individualized clinical approach.

Male reproductive cancers and infertility: a mutual relationship

Reproductive dysfunction and malignancies related to the male gender represent a serious health concern, whose incidence has significantly risen over the past years. Prior to treatment, testicular or prostate cancer patients often display poor semen characteristics similar to subfertile or infertile patients. This fact is underscored by cases where the malignancy is often diagnosed in males who undergo a general fertility screening. This review aims to examine the associations between male infertility and reproductive cancers focusing on common etiologies and biological mechanisms underlining these pathologies. Furthermore, we discuss compelling epidemiological data hypothesizing that male reproductive failure may act as a precursor of future andrological malignancies, including testicular or prostate cancer, thus providing a stimulus for a more specific research in male reproductive health and emphasizing the importance of this relation for physicians taking care of male patients with a reproductive disease.

Genome-wide analysis of DNA copy number alterations and loss of heterozygosity in intracranial germ cell tumors

BACKGROUNDS

Intracranial germ cell tumors (GCTs) are rare and heterogeneous with very little is known about their pathogenesis and underlying genetic abnormalities.

PROCEDURES

In order to identify candidate genes and pathways which are involved in the pathogenesis of these tumors, we have profiled 62 intracranial GCTs for DNA copy number alterations (CNAs) and loss of heterozygosity (LOH) by using single nucleotide polymorphism (SNP) array and quantitative real time PCR (qPCR).

RESULTS

Initially 27 cases of tumor tissues with matched blood samples were fully analyzed by SNP microarray and qPCR. Statistical analysis using the genomic identification of significant targets in cancer (GISTIC) tool identified 10 regions of significant copy number gain and 11 regions of significant copy number loss. While overall pattern of genomic aberration was similar between germinoma and nongerminomatous germ cell tumors (NGGCTs), a few subtype-specific peak regions were identified. Analysis by SNP array and qPCR was replicated using an independent cohort of 35 cases.

CONCLUSIONS

Frequent aberrations of CCND2 (12p13) and RB1 (13q14) suggest that Cyclin/CDK-RB-E2F pathway might play a critical role in the pathogenesis of intracranial GCTs. Frequent gain of PRDM14 (8q13) implies that transcriptional regulation of primordial germ cell specification might be an important factor in the development of this tumor.

Genomic characterization of testis cancer: association of alterations with outcome of clinical stage 1 mixed germ cell nonseminomatous germ cell tumor of the testis

OBJECTIVE

To identify genomic markers that are reliable in predicting lymph node metastases in clinical stage 1 non-seminomatous germ cell tumors (NSGCTs).

METHODS

Comparative genomic array technology was used to identify regions of genomic amplification or deletion in clinical stage 1 NSGCTs. Twelve stage 1 mixed germ cell testicular tumors were analyzed, which were obtained from 8 patients who had no evidence of nodal metastasis when retroperitoneal lymph node dissection (RPLND) had been performed (ie, were RPLND negative) and 4 patients who had nodal metastases (ie, were RPLND positive).

RESULTS

Differences between the genomic alterations associated with the two classes of tumors were identified. Genomic alterations previously reported in other subtypes of testicular tumors were observed in both metastatic and nonmetastatic cases. Statistically suggestive differences in mean copy number of the Y chromosome were found between metastatic and nonmetastatic cases (P = .0142).

CONCLUSION

This finding suggests the presence of chromosome Y deletions to be a potential genetic marker for prediction of mixed germ cell tumor progression. This is a first step toward identifying chromosomal markers of progression in testicular cancer in clinical stage 1 mixed germ cell NSGCT.

Novel retrotransposed imprinted locus identified at human 6p25

Differentially methylated regions (DMRs) are stable epigenetic features within or in proximity to imprinted genes. We used this feature to identify candidate human imprinted loci by quantitative DNA methylation analysis. We discovered a unique DMR at the 5′-end of FAM50B at 6p25.2. We determined that sense transcripts originating from the FAM50B locus are expressed from the paternal allele in all human tissues investigated except for ovary, in which expression is biallelic. Furthermore, an antisense transcript, FAM50B-AS, was identified to be monoallelically expressed from the paternal allele in a variety of tissues. Comparative phylogenetic analysis showed that FAM50B orthologs are absent in chicken and platypus, but are present and biallelically expressed in opossum and mouse. These findings indicate that FAM50B originated in Therians after divergence from Prototherians via retrotransposition of a gene on the X chromosome. Moreover, our data are consistent with acquisition of imprinting during Eutherian evolution after divergence of Glires from the Euarchonta mammals. FAM50B expression is deregulated in testicular germ cell tumors, and loss of imprinting occurs frequently in testicular seminomas, suggesting an important role for FAM50B in spermatogenesis and tumorigenesis. These results also underscore the importance of accounting for parental origin in understanding the mechanism of 6p25-related diseases.

Loss of heterozygosity of CDKN2A (p16INK4a) and RB1 tumor suppressor genes in testicular germ cell tumors

BACKGROUND

Testicular germ cell tumors (TGCTs) are the most frequent malignances in young adult men. The two main histological forms, seminomas and nonseminomas, differ biologically and clinically. pRB protein and its immediate upstream regulator p16INK4a are involved in the RB pathway which is deregulated in most TGCTs. The objective of this study was to evaluate the occurrence of loss of heterozygosity (LOH) of the CDKN2A (p16INK4a) and RB1 tumor suppressor genes in TGCTs. MATERIALS AND METHODS.: Forty TGCTs (18 seminomas and 22 nonseminomas) were analyzed by polymerase chain reaction using the restriction fragment length polymorphism or the nucleotide repeat polymorphism method.

RESULTS

LOH of the CDKN2A was found in two (6%) out of 34 (85%) informative cases of our total TGCT sample. The observed changes were assigned to two (11%) nonseminomas out of 18 (82%) informative samples. Furthermore, LOH of the RB1 was detected in two (6%) out of 34 (85%) informative cases of our total TGCT sample. Once again, the observed changes were assigned to two (10.5%) nonseminomas out of 19 (86%) informative samples. Both LOHs of the CDKN2A were found in nonseminomas with a yolk sac tumor component, and both LOHs of the RB1 were found in nonseminomas with an embryonal carcinoma component.

CONCLUSIONS

The higher incidence of observed LOH in nonseminomas may provide a clue to their invasive behavior.

X-linked ichthyosis: an oculocutaneous genodermatosis

X-linked ichthyosis (XLI) is an X-linked recessive disorder of cutaneous keratinization with possible extracutaneous manifestations. It was first described as a distinct type of ichthyosis in 1965. XLI is caused by a deficiency in steroid sulfatase activity, which results in abnormal desquamation and a retention hyperkeratosis. XLI is usually evident during the first few weeks of life as polygonal, loosely adherent translucent scales in a generalized distribution that desquamate widely. These are quickly replaced by large, dark brown, tightly adherent scales occurring primarily symmetrically on the extensor surfaces and the side of the trunk. In addition, extracutaneous manifestations such as corneal opacities, cryptorchidism, and abnormalities related to contiguous gene syndromes may be observed. Diagnosis of XLI is usually made clinically, as the histopathology is nonspecific, but confirmation may be obtained through either biochemical or genetic analysis. Treatment should focus on cutaneous hydration, lubrication, and keratolysis and includes topical moisturizers and topical retinoids.

Molecular events in germ cell tumours: linking chromosome-12 gain, acquisition of pluripotency and response to cisplatin

Germ cell tumours (GCTs) represent the leading cause of cancer-related morbidity and mortality in young men aged 18-35 years. Transformation of the cell of origin results in tumours with several unique properties. GCTs are characterized by gain of the short arm of chromosome 12 in almost all cases, a frequency of genomic alteration not seen in any other solid tumours. GCTs are truly pluripotent, giving rise to cells of somatic and extra-embryonic lineages, which results in tumours with a spectrum of differentiation that rivals that seen in normal embryogenesis and development. Despite the presence of genomic instability and many oncogenic changes, GCTs are highly curable, even in the metastatic setting, due to their extreme sensitivity to cisplatin-based chemotherapy. In this review we highlight some of the molecular events associated with the genesis, differentiation and chemotherapeutic response of these tumours, and discuss how these alterations are linked with biological features unique to germ cells.

Intratubular transplantation as a strategy for establishing animal models of testicular germ cell tumours

Testicular germ cell tumours (TGCTs) are prevalent cancers among young men. Currently, there is no reliable animal model for TGCTs. To establish such animal models, we have explored the possibility of intratubular testicular transplantation as means to deliver tumour cells into the seminiferous tubules of host animals. Our results demonstrated that transplanted cells could effectively populate the testis of a recipient mouse and develop into TGCTs. In addition, the donor cells could be transfected with a specific transgene before transplantation, thereby providing an approach to evaluate the specific effects of gene functions in the oncogenic processes. Hence, depending on selection of specific donor cells or mixtures of donor cells, transplantation models of TGCTs could be significant for studies on the pathogenesis, diagnosis and therapies of such a prevalent and important cancer in men.

Activation of ERK signaling pathway reduces the chemotherapy sensitivity in gastric cancer cells

AIM: To investigate the relationship between the activation of mitogen-activated protein kinase (MAPK)/extracelluar regulated protein kinases (ERK) signaling pathway and chemoresistance in human gastric cancer cell lines SGC7901 and BGC823.

METHODS: Cells were exposed to etoposide with or without PD98059 (a special inhibitor of MAPK/ERK pathway). Cell cycle distribution and cell apoptosis analysis were determined using flow cytometry and Hoechst 33258 staining. Cytotoxicity was assessed by determining cell survival with 3-(4, 5-dimethyl thiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT). Western blotting was performed to evaluate the phosphorylation level of ERK1/2 and protein expression of c-Myc and P53.

RESULTS: Etoposide caused a time- and dose-dependent reduction of cell viability in SGC7901 and BGC823 cells. PD98059 enhanced the cell inhibitory efficiency of etoposide. Compared with control group, the apoptosis rate was elevated in etoposide group (19.48% ± 1.57% vs 5.67% ± 0.81%, 17.38% ± 1.49% vs 4.97% ± 0.73%, all P < 0.01). Cells treated with and PD98059 showed significantly higher level of apoptotic phenotype than those treated with etoposide alone. The apotosis rate was 34.35% ± 2.84% and 32.11% ± 3.25% in etoposide and PD98059 groups, respectively (P < 0.01). Phosphorylation level of ERK1/2 and expression of c-Myc were significantly induced by etoposide in a time-dependent manner, but there was slight effect on protein expression of P53. PD98059 up-regulated expression of P53 and suppressed the up-regulated c-Myc expression induced by etoposide, strikingly.

CONCLUSION: Chemotherapy agent etoposide was able to activate MAPK/ERK signaling pathway of gastric cancer cells SGC7901 and BGC823, which decrease the chemotherapy sensitivity via suppressing the expression of P53 and enhancing the expression of c-Myc. This may be one of the mechanisms responsible for gastric cancer chemoresistance.

Origin of pluripotent germ cell tumours: the role of microenvironment during embryonic development

Carcinoma in situ (CIS) testis, known also as intratubular germ cell neoplasia, is the cancer stem cell from which the great majority of testicular germ cell derived tumours (TGCTs) of the testis arise. TGCTs can proliferate into morphologically homogeneous seminomas or can differentiate into virtually any type of tissue and form teratomas (non-seminomas). CIS cells display a close phenotypic similarity to fetal germ cells (primordial germ cells or gonocytes) suggesting an origin due to a developmental delay or arrest of differentiation of early germ cells. The pluripotency of these neoplasms has recently been explained by a close resemblance of their expression profile to that of embryonic inner cell mass cells studied in culture as embryonic stem cells, with high expression of transcription factors associated with pluripotency, such as NANOG and OCT3/4, as well as proteins found in several tissue specific stem cells, such as TFAP2C (AP-2gamma) or KIT. CIS and seminomas highly express a number of pre-meiotic germ cell specific genes, which are down-regulated during development to non-seminomas, while the expression of other embryonic markers, such as SOX2, is up-regulated. The mechanistic pathways and causative factors remain to be elucidated of both the initial transformation of fetal germ cells into CIS cells and the progression of CIS cells into an invasive tumour in the young adult. However, evidence supported by epidemiological studies indicate that disturbances in the hormonal microenvironment of the differentiating gonads may results in both the neoplasia and a host of other problems later in life, such as genital malformations, decreased spermatogenesis, and signs of hypogonadism.

Clinical and genetic aspects of testicular germ cell tumours

In this paper we review clinical and genetic aspects of testicular germ cell tumours (TGCTs). TGCT is the most common type of malignant disorder in men aged 1540 years. Its incidence has increased sharply in recent years. Fortunately, survival of patients with TGCT has improved enormously, which can chiefly be attributed to the cisplatin-based polychemotherapy that was introduced in the nineteen eighties to treat patients with metastasized TGCT. In addition, new strategies have been developed in the surgical approach to metastasized/non-metastasized TGCT and alterations have been made to the radiotherapy technique and radiation dose for seminoma. Family history of TGCT is among the strongest risk factors for this tumour type. Although this fact and others suggest the existence of genetic predisposition to develop TGCT, no germline mutations conferring high risk of developing TGCT have been identified so far. A small deletion, referred to as gr/gr, identified on the Y chromosome is probably associated with only a modest increase in TGCT risk, and linkage of familial TGCT to the Xq27 region has not been confirmed yet. Whether highly penetrant TGCT-predisposing mutations truly exist or familial clustering of TGCT can be explained by combinations of weak predispositions, shared in utero or postnatal risks factors and coincidental somatic mutations is an intriguing puzzle, still waiting to be solved.

Vector integration is nonrandom and clustered and influences the fate of lymphopoiesis in SCID-X1 gene therapy

Recent reports have challenged the notion that retroviruses and retroviral vectors integrate randomly into the host genome. These reports pointed to a strong bias toward integration in and near gene coding regions and, for gammaretroviral vectors, around transcription start sites. Here, we report the results obtained from a large-scale mapping of 572 retroviral integration sites (RISs) isolated from cells of 9 patients with X-linked SCID (SCID-X1) treated with a retrovirus-based gene therapy protocol. Our data showed that two-thirds of insertions occurred in or very near to genes, of which more than half were highly expressed in CD34(+) progenitor cells. Strikingly, one-fourth of all integrations were clustered as common integration sites (CISs). The highly significant incidence of CISs in circulating T cells and the nature of their locations indicate that insertion in many gene loci has an influence on cell engraftment, survival, and proliferation. Beyond the observed cases of insertional mutagenesis in 3 patients, these data help to elucidate the relationship between vector insertion and long-term in vivo selection of transduced cells in human patients with SCID-X1.

MAD2 expression and its significance in mitotic checkpoint control in testicular germ cell tumour

Chromosomal instability (CIN) is a common characteristic in testicular germ cell tumour (TGCT). A functional mitotic checkpoint control is important for accurate chromosome segregation during mitosis. Mitotic arrest deficient 2 (MAD2) is a key component of this checkpoint and inactivation of MAD2 is correlated with checkpoint impairment. The aim of this study was to investigate the function of mitotic checkpoint control in TGCT cells and to study its association with MAD2 expression using 8 TGCT cell lines as well as 23 TGCT tissue samples. We found that in response to microtubule disruption, 6 of 8 TGCT cell lines (75%) failed to arrest in mitosis demonstrated by the decreased mitotic index and aberrant expression of mitosis regulators, indicating that mitotic checkpoint defect is a common event in TGCT cells. This loss of mitotic checkpoint control was correlated with reduced MAD2 protein expression in TGCT cell lines implicating that downregulation of MAD2 may play a critical role in an impaired mitotic checkpoint control in these cells. In addition, immunohistochemistry studies on 23 seminomas and 12 normal testis tissues demonstrated that nuclear expression of MAD2 was much lower in seminomas (p<0.0001) but cytoplasmic MAD2 expression was higher in seminomas (p=0.06) than normal samples. Our results suggest that aberrant MAD2 expression may play an essential role in a defective mitotic checkpoint in TGCT cells, which may contribute to CIN commonly observed in TGCT tumours.

The Y-encoded TSPY protein: a significant marker potentially plays a role in the pathogenesis of testicular germ cell tumors

The testis-specific protein Y-encoded (TSPY) gene is the putative gene for the gonadoblastoma locus on the Y chromosome (GBY) that predisposes dysgenetic gonads of intersex patients to gonadoblastoma development. TSPY is expressed at high levels in gonadoblastoma tissues, supporting its possible oncogenic function in this type of germ cell tumors. To explore the possibility that this Y chromosome gene is also involved in pathogenesis of the more common testicular germ cell tumors (TGCTs), we have conducted various expression studies using immunohistochemistry, Western blotting, and reverse transcription-polymerase chain reaction analysis on 171 cases of TGCTs and selected normal testis controls. Our results demonstrated that TSPY protein is abundantly expressed in the precursor, carcinoma in situ or intratubular germ cell neoplasia unclassified, and seminoma, but only minimally or not expressed in various types of nonseminomas. TSPY coexpresses with established germ cell tumor markers (such as placental-like alkaline phosphatase, c-KIT, OCT4) and proliferative markers (such as Ki-67 and cyclin B1) in the same tumor cells at both RNA and protein levels. Ectopic TSPY expression in cultured cells up-regulates progrowth genes, including those at chromosome 12p13, frequently gained/amplified in TGCTs. Our results suggest that TSPY, in combination with other markers, could be an important marker for diagnosis and subclassification of TGCTs and support its role in the pathogenesis of both gonadoblastoma and TGCTs.

Culture adaptation of embryonic stem cells echoes germ cell malignancy

Teratocarcinomas are a subset of tumours that result from the neoplastic transformation of primordial germ cells. Such germ cell tumours (GCT) are histologically heterogeneous, reflecting a capacity for differentiation (pluripotency) of their embryonal carcinoma (EC) stem cells. However, malignant evolution of these tumours may ultimately correlate with a decrease in pluripotency, because this would tend to increase the propensity of EC cells for self-renewal. Human embryonic stem (ES) cells, derived from early blastocysts, closely resemble EC cells and, on prolonged culture in vitro, acquire progressive genetic changes that show striking similarity to those seen in GCT (e.g. gain of material from chromosome 12). In parallel, these abnormal ES cells show enhanced population growth rates and plating efficiencies, indicative of their adaptation to culture conditions. Understanding the mechanisms that drive such culture adaptation of ES cells may also provide insights into the development and progression of GCT.

Endometrioid-like yolk sac and Sertoli-Leydig cell tumors in a carrier of a Y heterochromatin insertion into 1qh region: a causal association?

We describe the case of a young woman showing yolk sac tumors (YST) and a Sertoli-Leydig cell tumor (SLCT) in the right ovary, with recurrences in the right adnexum and with hepatic metastasis. To our knowledge, YST and SLCT have never been described as components of the same tumor or reported as associated in the same patient. The patient's karyotype showed the presence of Y chromosome inserted into the 1qh region; the inserted region corresponded to Yq12 heterochromatin. LOH analysis revealed 1p36 paternal allele loss in the proband tumor, thus supporting a germ cell origin for the tumor. The presence of Y heterochromatin in 1qh DNA might induce disturbances in the normal regulation of oncogenes located in 1q.

Adaptation to culture of human embryonic stem cells and oncogenesis in vivo

The application of human embryonic stem cells (HESCs) to provide differentiated cells for regenerative medicine will require the continuous maintenance of the undifferentiated stem cells for long periods in culture. However, chromosomal stability during extended passaging cannot be guaranteed, as recent cytogenetic studies of HESCs have shown karyotypic aberrations. The observed karyotypic aberrations probably reflect the progressive adaptation of self-renewing cells to their culture conditions. Genetic change that increases the capacity of cells to proliferate has obvious parallels with malignant transformation, and we propose that the changes observed in HESCs in culture reflect tumorigenic events that occur in vivo, particularly in testicular germ cell tumors. Further supporting a link between culture adaptation and malignancy, we have observed the formation of a chromosomal homogeneous staining region in one HESC line, a genetic feature almost a hallmark of cancer cells. Identifying the genes critical for culture adaptation may thus reveal key players for both stem cell maintenance in vitro and germ cell tumorigenesis in vivo.

Biology and Genetics of Adult Male Germ Cell Tumors

Adult male germ cell tumors (GCTs) arise by transformation of totipotent germ cells. They have the unique potential to activate molecular pathways, in part mimicking those occurring during gametogenesis and normal human development, as evidenced by the array of histopathologies observed in vivo. Recent expression profiling studies of GCTs along with advances in embryonic stem-cell research have contributed to our understanding of the underlying biology of the disease. Gain of the short arm of chromosome 12 detected in almost all adult GCTs appears to be multifunctional in germ cell tumorigenesis on the basis of the observed overexpression of genes mapped to this region involved in maintenance of pluripotency and oncogenesis. Expression signatures associated with the different histopathologies have yielded clues as to the functional mechanisms involved in GCT invasion, loss of pluripotency, and lineage differentiation. Genomic and epigenomic abnormalities that contribute to or cause these events have been identified by traditional genome analyses and continue to be revealed as genome-scanning technologies develop. Given the high sensitivity of most GCTs to cisplatin-based treatment, these tumors serve as an excellent model system for the identification of factors associated with drug resistance, including differentiation status and acquisition of genomic alterations. Overall, adult male GCTs provide a unique opportunity for the examination of functional links between transformation and pluripotency, genomic and epigenomic abnormalities and lineage differentiation, and the identification of genetic features associated with chemotherapy resistance.

Teratoma in an adolescent with malignant transformation into embryonal rhabdomyosarcoma: case report

BACKGROUND

The somatic type tumors are occasionally found in nonseminomatous germ cell tumors in men. These malignancies are presumed to arise from malignant transformation (MT) of teratoma or by differentiation of totipotential germ cell.

OBSERVATION

A case of MT of germ cell tumor in 17-year-old male into embryonal rhabdomyosarcoma is described. The histopathologic diagnosis was that of embryonal rhabdomyosarcoma in which no germ cell elements were found. The germ cell origin of transformed histology is supported by cytogenetic analysis (isochromosome 12p), and elevated alpha(1)-fetoprotein. Despite intensive therapy the patient died.

CONCLUSIONS

MT of teratoma is rare entity with poor prognosis.

Epigenetic silencing of the putative tumor suppressor gene testisin in testicular germ cell tumors

PURPOSE

Testisin, a serine protease abundantly expressed only in normal testes, is thought to be a tumor suppressor gene silenced by aberrant methylation in testicular germ cell tumors (TGCT). This study aimed at identifying the CpG sites relevant for testisin gene silencing when methylated and evaluating the potential of aberrant methylation as a biomarker in TGCT.

METHODS

Bisulfite sequencing and subsequent real-time RT-PCR were carried out in germ cell tumor cell lines and a cervical carcinoma cell line to reveal CpG sites implicated in testisin gene silencing. The normalized index of methylation (NIM) and the relative gene expression (RGE) were calculated in 33 TGCT and 19 normal testicular tissue samples by quantitative methylation-specific PCR (QMSP) and real-time RT-PCR.

RESULTS

CpG sites in the 5'untranslated region proved to be relevant for testisin gene silencing when methylated. Targeting these CpG sites by QMSP, we demonstrated that the median NIM was 8.6 times higher in the TGCT group than in normal testicular samples. This was associated with a median 23.6 times lower RGE in the TGCT probes. Non-seminomas had a significantly higher NIM than seminomas, but RGE was downregulated to comparable levels in both subgroups. QMSP was highly sensitive and distinguished TGCT from normal samples with excellent specificity.

CONCLUSIONS

Our results demonstrate for the first time that aberrant methylation of specific CpG sites near the transcription initiation site is an important factor in testisin gene silencing in TGCT.

A 2-year-old baby with Downs syndrome, cryptorchidism and testicular tumour

Seminomas are rare germ cell tumours. It occurs usually in men aged over 50 years. Seminomas differ genetically and clinically from germ cell tumours. They have a late age of onset and rarely metastasise. The incidence of testicular carcinoma (seminoma) in patients of Down syndrome has recently been emphasised. One of the predisposing factors for seminoma is undescended testis which not only results in spermatogenic arrest but also in carcinoma in situ. This triad of abnormalities that is cryptorchidism, oligozoospermia and testicular cancer is known as testicular dysgenesis syndrome (TDS). Since there is an increased incidence of tumourogenesis in Down syndrome cases the cryptorchid condition may result in an increased risk for testicular carcinogenesis and its early onset and poor prognosis. Therefore all Down syndrome cases with cryptorchidism should be counselled to go in for surgical descent of testis at the earliest age and also to come for regular follow up for early detection for any foci of malignancy. This is the youngest testicular seminoma ever reported in human. This tumour occurred in a 2-year-old child and it is possible that Trisomy 21 may predispose to early onset of seminoma and such cases should be under regular follow up. Thus improved understanding and identification of various urogenital anomalies associated with Down syndrome will aid in better management of these cases. This case report and review of literature all suggest that Down syndrome is associated with an increased risk of development of seminoma and that too at an early age. This advocates a need for thorough gonadal examination in all cases of Down syndrome.

Developmental model for the pathogenesis of testicular carcinoma in situ: genetic and environmental aspects

Carcinoma in situ testis (CIS), also known as intratubular germ cell neoplasia (ITGCN), is a pre-invasive precursor of testicular germ cell tumours, the commonest cancer type of male adolescents and young adults. In this review, evidence supporting the hypothesis of developmental origin of testicular germ cell cancer is summarized, and the current concepts regarding aetiology and pathogenesis of this disease are critically discussed. Comparative studies of cell surface proteins (e.g. PLAP and KIT), some of the germ cell-specific markers (e.g. MAGEA4, VASA, TSPY and NY-ESO-1), supported by studies of regulatory elements of the cell cycle (e.g. p53, CHK2 and p19-INK4d) demonstrated a close similarity of CIS to primordial germ cells and gonocytes, consistent with the pre-meiotic origin of CIS. Recent gene expression profiling studies showed that CIS cells closely resemble embryonic stem cells (ESCs). The abundance of factors associated with pluripotency (NANOG and OCT-3/4) and undifferentiated state (AP-2gamma) may explain the remarkable pluripotency of germ cell neoplasms, which are capable of differentiating to various somatic tissue components of teratomas. Impaired gonadal development resulting in the arrest of gonocyte differentiation and retention of its embryonic features, associated with an increasing genomic instability, is the most probable model for the pathogenesis of CIS. Genomic amplification of certain chromosomal regions, e.g. 12p, may facilitate survival of CIS and further invasive progression. Genetic studies, have so far not identified gene polymorphisms predisposing to the most common non-familial testicular cancer, but this research has only recently begun. Association of CIS with other disorders, such as congenital genital malformations and some forms of impaired spermatogenesis, all rising in incidence in a synchronous manner, led to the hypothesis that CIS might be a manifestation of testicular dysgenesis syndrome (TDS). The aetiology of TDS including testicular cancer remains to be elucidated, but epidemiological trends suggest a primary role for environmental factors, probably combined with genetic susceptibility.

Testicular germ-cell cancer

Testicular germ-cell tumours (TGCTs) represent the model of a curable malignancy; sensitive tumour markers, accurate prognostic classification, logical series of management trials, and high cure rates in both seminomas and non-seminomas have enabled a framework of effective cancer therapy. Understanding the molecular biology of TGCT could help improve treatment of other cancers. The typical presentation in young adults means that issues of long-term toxicity become especially important in judging appropriate management. A focus of recent developments has been to tailor aggressiveness of treatment to the severity of the prognosis. Recent changes affect the most common subtypes and include the reduction of chemotherapy for patients who have metastastic non-seminomas and a good prognosis, and alternatives to adjuvant radiotherapy in stage I seminomas. We summarise advances in the understanding and management of TGCT during the past decade.

Testicular germ cell tumours: the paradigm of chemo-sensitive solid tumours

Testicular germ cell tumours (TGCTs) are the most frequent solid malignant tumour in men 20-40 years of age and the most frequent cause of death from solid tumours in this age group. Up to 50% of the patients suffer from metastatic disease at diagnosis. The majority of metastatic testicular cancer patients, in contrast to most other metastatic solid tumours, can be cured with highly effective cisplatin-based chemotherapy. From a genetic point of view, almost all TGCTs in contrast to solid tumours are characterised by the presence of wild type p53. High p53 expression levels are associated with elevated Mdm2 levels and a loss of p21(Waf1/Cip1) expression suggesting a changed functionality of p53. Expression levels of other proteins involved in the regulation of cell cycle progression indicate a deregulated G1-S phase checkpoint in TGCTs. After cisplatin-induced DNA damage, the increasing levels of p53 lead to the trans-activation of a number of genes but not of p21(Waf1/Cip1), preferentially directing TGCT cells into apoptosis or programmed cell death, both via the mitochondrial and the death receptor apoptosis pathways. The sensitivity of TGCTs to chemotherapeutic drugs may lay in the susceptibility of germ cells to apoptosis. Taken together, this provides TGCT as a tumour type model to investigate and understand the molecular determinants of chemotherapy sensitivity of solid tumours. This review aims to summarise the current knowledge on the biological basis of cisplatin-induced apoptosis and response to chemotherapy in TGCTs.

Microinvasive germ cell tumor of the testis

Microinvasive germ cell tumor (MGCT) consists of a limited number of malignant germ cells in the intertubular tissue of the testis. The cells have large nuclei, prominent nucleoli, abundant clear cytoplasm, and distinct cellular borders in hematoxylin and eosin staining. MGCT can be the first stage of malignancy in the development of testicular germ cell tumor (TGCT). Biopsies from men with maldescended testes have been reported to contain intratubular germ cell neoplasia, unclassified (IGCN) and MGCT in 1.8% of the examined cases (95% CI 0.5-4.6%). MGCT has also been found in testes of subfertile men and in the contralateral testis of patients with TGCT. MGCT is a frequent finding (19%) in the testicular tissue adjacent to an overt TGCT. Men with a high risk of TGCT may gain from screening for precursor lesions of TGCT with ultrasonography of the testes followed by a testicular biopsy if suspicious abnormalities are found: Treatment is high-voltage radiotherapy for intratubular germ cell neoplasia (IGCN), and orchidectomy for MGCT and germ cell tumor in situ, either intratubular seminoma or intratubular embryonal carcinoma. After local treatment, patients with precursor lesions can be followed with a surveillance program. The mRNA levels of invasion-related genes were evaluated based on a DNA microarray data set, and we found two gene abnormalities most relevant for the invasion of malignant germ cells: matrix metalloproteinase 9 (MMP9) and plasminogen activator, urokinase (PLAU) genes were up-regulated in a study comparing tissue samples of TGCT and IGCN.

Testicular germ-cell tumours in a broader perspective

The germ-cell tumours are a fascinating group of neoplasms because of their unusual biology and the spectacular therapeutic results that have been obtained in these tumours. Traditionally, this group of neoplasms is presented in an organ-oriented approach. However, recent clinical and experimental data convincingly demonstrate that these neoplasms are one disease with separate entities that can manifest themselves in different anatomical sites. We propose five entities, in which the developmental potential is determined by the maturation stage and imprinting status of the originating germ cell. Recent progress begins to explain the apparent unpredictable development of germ-cell tumours and offers a basis for understanding their exquisite sensitivity to therapy.

Overexpression of genes on 16q associated with cisplatin resistance of testicular germ cell tumor cell lines

Testicular germ-cell tumors (TGCTs) show exquisite sensitivity to cisplatin-based chemotherapy, and therefore this is considered a good model system for studying the mechanism of chemotherapy resistance. Although the genetic alterations related to TGCT have been well studied, little is known about the genetic basis of chemotherapy resistance, which occurs in a small proportion of TGCTs. In this study, we investigated genomic and expression differences between three cisplatin-sensitive and their paired cisplatin-resistant lines using combined whole-genome screen approaches. Comparative genomic hybridization (CGH) analysis on chromosomes revealed genetic differences between the resistant and parent cell lines in each pair, but did not show any consistent chromosome changes in all three lines. Microarray CGH analysis generated some additional information of DNA copy number gains and losses including some important oncogenes, tumor-suppressor genes, and drug-resistance-related genes. However, no consistent genomic region changes were found in the three cell lines. Interestingly, when comparative expressed sequence hybridization, a technique for gene expression profiling along chromosomes, was applied, we discovered a consistently overexpressed chromosomal region in all three resistant lines compared with their parent lines. The minimum overlapping chromosomal region is at 16q22-23. Further definition of genes in this chromosomal region will aid our understanding of the mechanism of cisplatin resistance and may offer novel therapeutic targets.

Microinvasive germ cell tumour (MGCT) adjacent to testicular germ cell tumours

AIMS

To examine the occurrence and prognostic significance of intratubular germ cell neoplasia (IGCN) and microinvasive germ cell tumour (MGCT) in tissue adjacent to testicular germ cell tumours (TGCT) in adults.

METHODS AND RESULTS

The study was based on two Danish studies of adult patients with stage I TGCT and included 255 patients. Of 106 patients with seminoma, 75 [71%, 95% confidence interval (CI) 61, 79] had IGCN without MGCT and nine (8%, CI 4, 15) had both IGCN and MGCT. Of 149 patients with non-seminoma, 62 (42%, CI 34, 50) had IGCN without MGCT, and 32 (22%, CI 15, 29) had both IGCN and MGCT. Non-seminomas with a seminoma component were more often associated with MGCT (23 of 54 testes, 43%, CI 29, 57) than were non-seminomas without this component (nine of 95 testes, 10%, CI 4, 17) (P < 0.000 05, Fisher's exact test). Relapse-free survival was not influenced by the concomitant presence of the two precursor stages in the testes (P = 0.36, and P = 0.19, log rank test, respectively).

CONCLUSIONS

MGCT was a relatively frequent finding in testes adjacent to a macroscopic TGCT. However, neither IGCN nor MGCT predicted relapse for patients with stage I TGCT.