Parental occupations at birth and risk of adult testicular germ cell tumors in offspring: a French nationwide case-control study

Background

Testicular germ cell tumors (TGCT) are the most frequent cancer in young men in developed countries. Parental occupational exposures during early-life periods are suspected to increase TGCT risk. The objective was to estimate the association between parental occupations at birth and adult TGCT.

Methods

A case-control study was conducted, including 454 TGCT cases aged 18-45 from 20 French university hospitals, matched to 670 controls based on region and year of birth. Data collected from participants included parental jobs at birth coded according to the International Standard Classification of Occupation-1968 and the French nomenclature of activities-1999. Odds ratios (OR) for TGCT and 95% confidence intervals (CI) were estimated using conditional logistic regression, adjusting for TGCT risk factors.

Results

Paternal jobs at birth as service workers (OR = 1.98, CI 1.18-3.30), protective service workers (OR = 2.40, CI 1.20-4.81), transport equipment operators (OR = 1.96, CI 1.14-3.37), specialized farmers (OR = 2.66, CI 1.03-6.90), and maternal jobs as secondary education teachers (OR = 2.27, CI 1.09-4.76) or in secondary education (OR = 2.35, CI 1.13-4.88) were significantly associated with adult TGCT. The risk of seminoma was increased for the above-mentioned paternal jobs and that of non-seminomas for public administration and defence; compulsory social security (OR = 1.99, CI 1.09-3.65); general, economic, and social administration (OR = 3.21, CI 1.23-8.39) for fathers; and secondary education teacher (OR = 4.67, CI 1.87-11.67) and secondary education (OR = 3.50, CI 1.36-9.01) for mothers.

Conclusion

Some paternal jobs, such as service workers, transport equipment operators, or specialized farmers, and maternal jobs in secondary education seem to be associated with an increased risk of TGCT with specific features depending on the histological type. These data allow hypotheses to be put forward for further studies as to the involvement of occupational exposures in the risk of developing TGCT, such as exposure to pesticides, solvents, or heavy metals.

Sub-chronic cadmium and lead compound exposure induces reproductive toxicity and development of testicular germ cell neoplasia in situ in murine model: Attenuative effects of resveratrol

Cadmium and lead are widespread, nonbiodegradable heavy metals of perpetual environmental concerns. The present study aimed to evaluate whether sub-chronic exposure to cadmium chloride (CdCl₂ ) and lead acetate [Pb(CH₃ COO)₂ ] induces reproductive toxicity and development of testicular germ cell neoplasia in situ (GCNIS) in swiss albino mice. The effects of resveratrol to reverse the metal-induced toxicity were also analyzed. The mice were randomly divided into four groups for metal treatments and two groups received two different doses of each metal, CdCl₂ (0.25 and 0.5 mg/kg) and Pb(CH₃ COO)₂ (3 and 6 mg/kg). The fourth group received oral doses of 20 mg/kg resveratrol in combination with 0.5 mg/kg CdCl₂ or 6 mg/kg Pb(CH₃ COO)₂ for 16 weeks. Toxic effects of both metals were estimated qualitatively and quantitatively by the alterations in sperm parameters, oxidative stress markers, testicular histology, and protein expressions of the treated mice. Pronounced perturbation of sperm parameters, cellular redox balance were observed with severe distortion of testicular histo-architecture in metal exposed mice. Significant overexpression of Akt cascade and testicular GCNIS marker proteins were recorded in tissues treated with CdCl₂ . Notable improvements were observed in all the evaluated parameters of resveratrol cotreated mice groups. Taken together, the findings of this study showed that long-term exposure to Cd and Pb compounds, induced acute reproductive toxicity and initiation of GCNIS development in mice. Conversely, resveratrol consumption abrogated metal-induced perturbation of spermatogenesis, testicular morphology, and the upregulation of Akt cascade proteins along with GCNIS markers, which could have induced the development of testicular cancer.

Targeting of Deregulated Wnt/β-Catenin Signaling by PRI-724 and LGK974 Inhibitors in Germ Cell Tumor Cell Lines

The majority of patients with testicular germ cell tumors (GCTs) can be cured with cisplatin-based chemotherapy. However, for a subset of patients present with cisplatin-refractory disease, which confers a poor prognosis, the treatment options are limited. Novel therapies are therefore urgently needed to improve outcomes in this challenging patient population. It has previously been shown that Wnt/β-catenin signaling is active in GCTs suggesting that its inhibitors LGK974 and PRI-724 may show promise in the management of cisplatin-refractory GCTs. We herein investigated whether LGK-974 and PRI-724 provide a treatment effect in cisplatin-resistant GCT cell lines. Taking a genoproteomic approach and utilizing xenograft models we found the increased level of β-catenin in 2 of 4 cisplatin-resistant (CisR) cell lines (TCam-2 CisR and NCCIT CisR) and the decreased level of β-catenin and cyclin D1 in cisplatin-resistant NTERA-2 CisR cell line. While the effect of treatment with LGK974 was limited or none, the NTERA-2 CisR exhibited the increased sensitivity to PRI-724 in comparison with parental cell line. Furthermore, the pro-apoptotic effect of PRI-724 was documented in all cell lines. Our data strongly suggests that a Wnt/β-catenin signaling is altered in cisplatin-resistant GCT cell lines and the inhibition with PRI-724 is effective in NTERA-2 CisR cells. Further evaluation of Wnt/β-catenin pathway inhibition in GCTs is therefore warranted.

Unraveling the dark matter, long non-coding RNAs, in male reproductive diseases: A narrative review

Recent advances in human transcriptome have revealed the fundamental and functional roles of long non-coding RNA in the susceptibility to diverse diseases and pathological conditions. They participate in wide range of biological processes such as the modulating of chromatin structure, transcription, translation, and post-translation modification. In addition, based on their unique expression profiles and their association with clinical abnormalities such as those of related to male reproductive diseases, they can be used to develop therapeutic methods and biomarkers for screening of the diseases. In this study, we will review the identified lncRNAs and their molecular functions in the pathogenesis of male reproductive diseases such as prostate cancer, benign prostatic hyperplasia, prostatitis, testicular cancer, varicocele, and sperm abnormalities.

Characterization of RNP Networks of PUM1 and PUM2 Post-Transcriptional Regulators in TCam-2 Cells, a Human Male Germ Cell Model

Mammalian Pumilio (PUM) proteins are sequence-specific, RNA-binding proteins (RBPs) with wide-ranging roles. They are involved in germ cell development, which has functional implications in development and fertility. Although human PUM1 and PUM2 are closely related to each other and recognize the same RNA binding motif, there is some evidence for functional diversity. To address that problem, first we used RIP-Seq and RNA-Seq approaches, and identified mRNA pools regulated by PUM1 and PUM2 proteins in the TCam-2 cell line, a human male germ cell model. Second, applying global mass spectrometry-based profiling, we identified distinct PUM1- and PUM2-interacting putative protein cofactors, most of them involved in RNA processing. Third, combinatorial analysis of RIP and RNA-Seq, mass spectrometry, and RNA motif enrichment analysis revealed that PUM1 and PUM2 form partially varied RNP-regulatory networks (RNA regulons), which indicate different roles in human reproduction and testicular tumorigenesis. Altogether, this work proposes that protein paralogues with very similar and evolutionary highly conserved functional domains may play divergent roles in the cell by combining with different sets of protein cofactors. Our findings highlight the versatility of PUM paralogue-based post-transcriptional regulation, offering insight into the mechanisms underlying their diverse biological roles and diseases resulting from their dysfunction.

Targeting Nodal and Cripto-1: Perspectives Inside Dual Potential Theranostic Cancer Biomarkers

BACKGROUND

Elucidating the mechanisms of recurrence of embryonic signaling pathways in tumorigenesis has led to the discovery of onco-fetal players which have physiological roles during normal development but result aberrantly re-activated in tumors. In this context, Nodal and Cripto-1 are recognized as onco-developmental factors, which are absent in normal tissues but are overexpressed in several solid tumors where they can serve as theranostic agents.

OBJECTIVE

To collect, review and discuss the most relevant papers related to the involvement of Nodal and Cripto-1 in the development, progression, recurrence and metastasis of several tumors where they are over-expressed, with a particular attention to their occurrence on the surface of the corresponding sub-populations of cancer stem cells (CSC).

RESULTS

We have gathered, rationalized and discussed the most interesting findings extracted from some 370 papers related to the involvement of Cripto-1 and Nodal in all tumor types where they have been detected. Data demonstrate the clear connection between Nodal and Cripto-1 presence and their multiple oncogenic activities across different tumors. We have also reviewed and highlighted the potential of targeting Nodal, Cripto-1 and the complexes that they form on the surface of tumor cells, especially of CSC, as an innovative approach to detect and suppress tumors with molecules that block one or more mechanisms that they regulate.

CONCLUSION

Overall, Nodal and Cripto-1 represent two innovative and effective biomarkers for developing potential theranostic anti-tumor agents that target normal as well as CSC subpopulations and overcome both pharmacological resistance and tumor relapse.

Octamer 4 expression and lymph node metastasis in ductal carcinoma of breast: Are they associated?

Purpose: Octamer 4 (Oct-4) is a transcription factor which is required for the self-renewal and pluripotency of embryonic stem cells and germ cells. In this study, we tried to examine the association of expression of Oct-4 with lymph node metastasis in ductal carcinoma of the breast. Methods: The study was conducted on a total of 45 cases of invasive ductal carcinoma of breast, no special type. Oct-4 expression was studied on paraffin-embedded sections by immunohistochemistry. Results: Oct-4 expression was seen in 22.2% of cases. No statistically significant association was found between the expression of Oct-4 and histological type, tumor size, histological grade, and lymph node metastasis. Of Oct-4 positive tumor, 80% of cases showed lymph node metastasis, as compared to 62.85% without Oct-4 expression. However, the association was statistically insignificant. Conclusion: Oct-4 expression can be a promising biomarker of carcinogenesis, metastatic potential, and prognosis of carcinoma breast. However, the study with larger sample size is needed to establish the clinicopathological potential of this biomarker.

On the Origin of Testicular Germ Cell Tumors: From Gonocytes to Testicular Cancer

Human primordial germ cells (PGCs) have been described in the yolk sac wall around the beginning of the third week. From week 4 to 5, they migrate under control of SCF/c-KIT signaling pathway to the genital ridge, where they become gonocytes. PGCs and gonocytes express classic pluripotency markers, such as KIT, NANOG, and OCT3/4 that, during spermatogonia differentiation, are gradually suppressed, and substituted by the expression of some germ cell specific genes, such as VASA, SOX17, and TSPY. These genes, during normal development of germ cells, are tightly regulated by epigenetic modification, in terms of microRNA expression and DNA methylation. In adolescents and young adults, testicular germ cell tumors (TGCT) have a common precursor, the germ cell neoplasia in situ (GCNIS); the hypothesis of their origin from PGCs or gonocytes, whose maturation is altered, is widely accepted. The origin of TGCT, probably starting at early stages of embryogenesis, seems to be a part of the Testicular Dysgenesis Syndrome (TDS) where some early PGC/gonocytes, for still unclear reasons, are blocked in their differentiation, retaining their early marker profile. In this paper, current knowledge on the combination of epidemiological and genomic factors, involved in the development of testicular germ cell tumors, is reviewed.

SPIN1 is a proto-oncogene and SPIN3 is a tumor suppressor in human seminoma

SPIN1 is necessary for normal meiotic progression in mammals. It is overexpressed in human ovarian cancers and some cancer cell lines. Here, we examined the functional significance and regulation of SPIN1 and SPIN3 in the TCam-2 human seminoma cell line. We found that while SPIN1 overexpression reduced apoptosis in these cells, SPIN3 overexpression induced it. Similarly, SPIN1 upregulated and SPIN3 downregulated CYCD1, which is a downstream target of the PI3K/AKT pathway and contributes to apoptosis resistance in cancer cell lines. It appears that SPIN1 is pro-oncogenic and SPIN3 acts as a tumor suppressor in TCam-2 cells. To our knowledge, this is the first report of SPIN3 tumor suppressor activity. However, both SPIN1 and SPIN3 stimulated cell cycle progression. In addition, using luciferase reporters carrying SPIN1 or SPIN3 mRNA 3′UTRs, we found that PUM1 and PUM2 targeted and repressed SPINs. We also found that PUM1 itself strongly stimulated apoptosis and moderately slowed cell cycle progression in TCam-2 cells, suggesting that PUM1, like SPIN3, is a tumor suppressor. Our findings suggest that acting, at least in part, through SPIN1 and SPIN3, PUM proteins contribute to a mechanism promoting normal human male germ cell apoptotic status and thus preventing cancer.

Sex Determination in the Mammalian Germline

Sexual reproduction crucially depends on the production of sperm in males and oocytes in females. Both types of gamete arise from the same precursor, the germ cells. We review the events that characterize the development of germ cells during fetal life as they commit to, and prepare for, oogenesis or spermatogenesis. In females, fetal germ cells enter meiosis, whereas in males they delay meiosis and instead lose pluripotency, activate an irreversible program of prospermatogonial differentiation, and temporarily cease dividing. Both pathways involve sex-specific molecular signals from the somatic cells of the developing gonads and a suite of intrinsic receptors, signal transducers, transcription factors, RNA stability factors, and epigenetic modulators that act in complex, interconnected positive and negative regulatory networks. Understanding these networks is important in the contexts of the etiology, diagnosis, and treatment of infertility and gonadal cancers, and in efforts to augment human and animal fertility using stem cell approaches.

Efficacy of targeted drugs in germ cell cancer cell lines with differential cisplatin sensitivity

Testicular germ cell tumors (TGCTs) are the most common malignancies in men between the age of 15 and 35. Although cisplatin-based chemotherapy is highly effective in advanced disease, approximately 20% of patients have an unfavorable prognosis due to primary or acquired cisplatin resistance. For these patients, new therapeutic options are urgently needed. In numerous tumor entities, combinations of monoclonal antibodies or kinase inhibitors with chemotherapy exerted promising preclinical or clinical results, which have led to new treatment concepts. This prompted us to investigate the activity of different targeted agents alone or in combination with cisplatin in a panel of TGCT cell lines.

Non-coding RNA in Spermatogenesis and Epididymal Maturation

Testicular germ and somatic cells express many classes of small ncRNAs, including Dicer-independent PIWI-interacting RNAs, Dicer-dependent miRNAs, and endogenous small interfering RNA. Several studies have identified ncRNAs that are highly, exclusively, or preferentially expressed in the testis and epididymis in specific germ and somatic cell types. Temporal and spatial expression of proteins is a key requirement of successful spermatogenesis and large-scale gene transcription occurs in two key stages, just prior to transcriptional quiescence in meiosis and then during spermiogenesis just prior to nuclear silencing in elongating spermatids. More than 60 % of these transcripts are then stockpiled for subsequent translation. In this capacity ncRNAs may act to interpret and transduce cellular signals to either maintain the undifferentiated stem cell population and/or drive cell differentiation during spermatogenesis and epididymal maturation. The assignation of specific roles to the majority of ncRNA species implicated as having a role in spermatogenesis and epididymal function will underpin fundamental understanding of normal and disease states in humans such as infertility and the development of germ cell tumours.

Cripto: Expression, epigenetic regulation and potential diagnostic use in testicular germ cell tumors

Type II germ cell tumors arise after puberty from a germ cell that was incorrectly programmed during fetal life. Failure of testicular germ cells to properly differentiate can lead to the formation of germ cell neoplasia in situ of the testis; this precursor cell invariably gives rise to germ cell cancer after puberty. The Nodal co-receptor Cripto is expressed transiently during normal germ cell development and is ectopically expressed in non-seminomas that arise from germ cell neoplasia in situ, suggesting that its aberrant expression may underlie germ cell dysregulation and hence germ cell cancer. Here we investigated methylation of the Cripto promoter in mouse germ cells and human germ cell cancer and correlated this with the level of CRIPTO protein expression. We found hypomethylation of the CRIPTO promoter in undifferentiated fetal germ cells, embryonal carcinoma and seminomas, but hypermethylation in differentiated fetal germ cells and the differentiated types of non-seminomas. CRIPTO protein was strongly expressed in germ cell neoplasia in situ along with embryonal carcinoma, yolk sac tumor and seminomas. Further, cleaved CRIPTO was detected in media from seminoma and embryonal carcinoma cell lines, suggesting that cleaved CRIPTO may provide diagnostic indication of germ cell cancer. Accordingly, CRIPTO was detectable in serum from 6/15 patients with embryonal carcinoma, 5/15 patients with seminoma, 4/5 patients with germ cell neoplasia in situ cells only and in 1/15 control patients. These findings suggest that CRIPTO expression may be a useful serological marker for diagnostic and/or prognostic purposes during germ cell cancer management.

Cross platform analysis of methylation, miRNA and stem cell gene expression data in germ cell tumors highlights characteristic differences by tumor histology

Background

Alterations in methylation patterns, miRNA expression, and stem cell protein expression occur in germ cell tumors (GCTs). Our goal is to integrate molecular data across platforms to identify molecular signatures in the three main histologic subtypes of Type I and Type II GCTs (yolk sac tumor (YST), germinoma, and teratoma).

Methods

We included 39 GCTs and 7 paired adjacent tissue samples in the current analysis. Molecular data available for analysis include DNA methylation data (Illumina GoldenGate Cancer Methylation Panel I), miRNA expression (NanoString nCounter miRNA platform), and stem cell factor expression (SABiosciences Human Embryonic Stem Cell Array). We evaluated the cross platform correlations of the data features using the Maximum Information Coefficient (MIC).

Results

In analyses of individual datasets, differences were observed by tumor histology. Germinomas had higher expression of transcription factors maintaining stemness, while YSTs had higher expression of cytokines, endoderm and endothelial markers. We also observed differences in miRNA expression, with miR-371-5p, miR-122, miR-302a, miR-302d, and miR-373 showing elevated expression in one or more histologic subtypes. Using the MIC, we identified correlations across the data features, including six major hubs with higher expression in YST (LEFTY1, LEFTY2, miR302b, miR302a, miR 126, and miR 122) compared with other GCT.

Conclusions

While prognosis for GCTs is overall favorable, many patients experience resistance to chemotherapy, relapse and/or long term adverse health effects following treatment. Targeted therapies, based on integrated analyses of molecular tumor data such as that presented here, may provide a way to secure high cure rates while reducing unintended health consequences.

HMGA2 expression distinguishes between different types of postpubertal testicular germ cell tumour

The group of postpubertal testicular germ cell tumours encompasses lesions with highly diverse differentiation – seminomas, embryonal carcinomas, yolk sac tumours, teratomas and choriocarcinomas. Heterogeneous differentiation is often present within individual tumours and the correct identification of the components is of clinical relevance. HMGA2 re‐expression has been reported in many tumours, including testicular germ cell tumours. This is the first study investigating HMGA2 expression in a representative group of testicular germ cell tumours with the highly sensitive method of quantitative real‐time PCR as well as with immunohistochemistry. The expression of HMGA2 and HPRT was measured using quantitative real‐time PCR in 59 postpubertal testicular germ cell tumours. Thirty specimens contained only one type of tumour and 29 were mixed neoplasms. With the exception of choriocarcinomas, at least two pure specimens from each subgroup of testicular germ cell tumour were included. In order to validate the quantitative real‐time PCR data and gather information about the localisation of the protein, additional immunohistochemical analysis with an antibody specific for HMGA2 was performed in 23 cases. Expression of HMGA2 in testicular germ cell tumours depended on the histological differentiation. Seminomas and embryonal carcinomas showed no or very little expression, whereas yolk sac tumours strongly expressed HMGA2 at the transcriptome as well as the protein level. In teratomas, the expression varied and in choriocarcinomas the expression was moderate. In part, these results contradict data from previous studies but HMGA2 seems to represent a novel marker to assist pathological subtyping of testicular germ cell tumours. The results indicate a critical role in yolk sac tumours and some forms of teratoma.

Increasing incidence of testicular cancer in the United States and Europe between 1992 and 2009

PURPOSE

Increasing in incidence, testicular cancer is the most commonly diagnosed cancer in young men in the USA and in Europe. We sought to determine contemporary trends in testicular cancer incidence in the USA and Europe.

METHODS

Testicular cancer incidence data covering the USA and Europe were extracted from the SEER-13 (SEER*Stat 8.0.1) and the EUREG databases, respectively. Trends were determined using JoinPoint 3.5.3.

RESULTS

Testicular germ cell tumor (TGCT) incidence among US males >15 years increased from 1992 (5.7/100,000) to 2009 (6.8/100,000) with a significant annual percentage change (APC: 1.1%, p < 0.001). Seminomas were 29% of all TGCTs in 15-26 year-olds, increasing to 78% in those 40+ years of age. TGCT rates were highest in White men (1992: 7.5/100,000; 2009: 8.6/100,000) followed by Hispanic men (1992: 4.0/100,000; 2009: 6.3/100,000) and lowest among Asian (1992: 2.0/100,000; 2009: 2.8/100,000) and Black men (1992: 0.7/100,000; 2009: 1.7/100,000). Significantly increasing incidence rates were observed in White men (APC: 1.2%, p < 0.001) and most prominently in Hispanic men, especially from 2002 to 2009 (APC: 5.6%, p < 0.01). Incidence of testicular cancer increased in 15 of 19 (79%) European countries analyzed (p < 0.05). Denmark (13.4/100,000 man-years), Switzerland (12.7/100,000 man-years), and Norway (12.7/100,000 man-years) exhibited the highest age-standardized rates, while Spain had the greatest APC (APC = 5.5, 95% CI 3.9-7.0%, p < 0.001).

CONCLUSIONS

Between 1992 and 2009, testicular cancer incidence in the USA and Europe continued to increase, most notably in US Hispanic, Northern European, Spanish, and younger and older populations.

Retinoblastoma protein (RB1) controls fate determination in stem cells and progenitors of the mouse male germline

Continual spermatogenesis is the cornerstone of male fertility and relies on the actions of an undifferentiated spermatogonial population comprised of stem cells and progenitors. A foundational spermatogonial stem cell (SSC) pool is established during postnatal development that serves as a self-renewing reservoir from which progenitor spermatogonia arise that transiently amplify in number before committing to terminal differentiation. At present, the underlying molecular mechanisms governing these actions are undefined. Using conditional mutant mouse models, we investigated whether function of the undifferentiated spermatogonial population during postnatal life is influenced by the tumor suppressor protein RB1. Spermatogenesis initiates in mice with conditional inactivation of Rb1 in prospermatogonial precursors, but the germline is progressively lost upon aging due to impaired renewal of the undifferentiated spermatogonial population. In contrast, continual spermatogenesis is sustained following Rb1 inactivation in progenitor spermatogonia, but some cells transform into a carcinoma in situ-like state. Furthermore, knockdown of Rb1 abundance within primary cultures of wild-type undifferentiated spermatogonia impairs maintenance of the SSC pool, and some cells are invasive of the basement membrane after transplant into recipient testes, indicating acquisition of tumorigenic properties. Collectively, these findings indicate that RB1 plays an essential role in establishment of a self-renewing SSC pool and commitment to the spermatogenic lineage within progenitor spermatogonia.

Raman microspectroscopic discrimination of TCam-2 cultures reveals the presence of two sub-populations of cells

TCam-2 cells are the main in vitro model for investigations into seminomatous tumors. However, despite their widespread use, questions remain regarding the cells' homogeneity and consequently how representative they are of seminomas. We assess the TCam-2 cell line using routine and novel authentication methods to determine its homogeneity, identify any cellular sub-populations and resolve whether any changes could be due to generational differentiation. TCam-2, embryonal carcinoma cells (2102EP) and breast cancer cell (MCF7) lines were assessed using qRT-PCR, immunocytochemistry, flow cytometry and short tandem repeat analyses. Raman maps of individual cells (minimum of 10) and single scan spectra from 200 cells per culture were obtained. TCam-2s displayed the characteristic marker gene expression pattern for seminoma, were uniform in size and granularity and short tandem repeat analysis showed no contamination. However, based only on physical parameters, flowcytometry was unable to differentiate between TCam-2 and 2102EPs. Raman maps of TCam-2s comprised three equally distributed, distinct spectral patterns displaying large intercellular single spectral variation. All other cells showed little variation. Principal component, cluster and local spectral angle analyses indicated that the TCam-2s contained two different types of cells, one of which comprised two subgroups and was similar to some 2102EP cells. Protein expression corroborated the presence of different cells and generational differences. The detailed characterization provided by the Raman spectra, augmented by the routine methods, provide substantiation to the long-held suspicion that TCam-2 are not homogeneous but comprise differing cell populations, one of which may be embryonal carcinoma in origin.

The rise of testicular germ cell tumours: the search for causes, risk factors and novel therapeutic targets

Since the beginning of the 20th century there has been a decline in the reproductive vitality of men within the Western world. The declining sperm quantity and quality has been associated with increased overt disorders of sexual development including hypospadias, undescended testes and type II testicular germ cell tumours (TGCTs). The increase in TGCTs cannot be accounted for by genetic changes in the population. Therefore exposure to environmental toxicants appears to be a major contributor to the aetiology of TGCTs and men with a genetic predisposition are particularly vulnerable. In particular, Type II TGCTs have been identified to arise from a precursor lesion Carcinoma in situ (CIS), identified as a dysfunctional gonocyte; however, the exact triggers for CIS development are currently unknown. Therefore the transition from gonocytes into spermatogonia is key to those studying TGCTs. Recently we have identified seven miRNA molecules (including members of the miR-290 family and miR-136, 463* and 743a) to be significantly changed over this transition period. These miRNA molecules are predicted to have targets within the CXCR4, PTEN, DHH, RAC and PDGF pathways, all of which have important roles in germ cell migration, proliferation and homing to the spermatogonial stem cell niche. Given the plethora of potential targets affected by each miRNA molecule, subtle changes in miRNA expression could have significant consequences e.g. tumourigenesis. The role of non-traditional oncogenes and tumour suppressors such as miRNA in TGCT is highlighted by the fact that the majority of these tumours express wild type p53, a pivotal tumour suppressor usually inactivated in cancer. While treatment of TGCTs is highly successful, the impact of these treatments on fertility means that identification of exact triggers, earlier diagnosis and alternate treatments are essential. This review examines the genetic factors and possible triggers of type II TGCT to highlight target areas for potential new treatments.

Markers of stem cells in human ovarian granulosa cells: is there a clinical significance in ART?

Background

The purpose of the study was to determine the incidence of gene expression of Oct-4 and DAZL, which are typical markers for stem cells, in human granulosa cells during ovarian stimulation in women with normal FSH levels undergoing IVF or ICSI and to discover any clinical significance of such expression in ART.

Methods

Twenty one women underwent ovulation induction for IVF or ICSI and ET with standard GnRH analogue-recombinant FSH protocol. Infertility causes were male and tubal factor. Cumulus–mature oocyte complexes were denuded separately and granulosa cells were analyzed for each patient separately using quantitative reverse-transcription–polymerase chain reaction analysis for Oct-4 and DAZL gene expression with G6PD gene as internal standard.

Results

G6PD and Oct-4 mRNA was detected in the granulosa cells in 47.6% (10/21). The median of Oct-4 mRNA/G6PD mRNA was 1.75 with intra-quarteral range from 0.10 to 98.21. The OCT-4 mRNA expression was statistically significantly correlated with the number of oocytes retrieved; when the Oct-4 mRNA expression was higher, then more than six oocytes were retrieved (p=0.037, Wilcoxon rank-sum). No detection of DAZL mRNA was found in granulosa cells. There was no additional statistically significant correlation between the levels of Oct-4 expression and FSH basal levels or estradiol peak levels or dosage of FSH for ovulation induction. No association was found between the presence or absence of Oct-4 mRNA expression in granulosa cells and ovarian response to gonadotropin stimulation. Also, no influence on pregnancy was observed between the presence or absence of Oct-4 mRNA expression in granulosa cells or to its expression levels accordingly.

Conclusions

Expression of OCT-4 mRNA, which is a typical stem cell marker and absence of expression of DAZL mRNA, which is a typical germ cell marker, suggest that a subpopulation of luteinized granulosa cells in healthy ovarian follicles (47.6%) consists of stem cells, which are not originated from primordial germ cells. Absence of Oct-4 gene expression in more than half of the cases means probably the end of the productive journey of these cells, towards the oocyte.

DICER1 RNase IIIb domain mutations are infrequent in testicular germ cell tumours

BACKGROUND

Testicular Germ Cell Tumours (TGCT) are the most frequently occurring malignancy in males from 15-45 years of age. They are derived from germ cells unable to undergo physiological maturation, although the genetic basis for this is poorly understood. A recent report showed that mutations in the RNase IIIb domain of DICER1, a micro-RNA (miRNA) processing enzyme, are common in non-epithelial ovarian cancers. DICER1 mutations were found in 60% of Sertoli-Leydig cell tumours, clustering in four codons encoding metal-binding sites. Additional analysis of 14 TGCT DNA samples identified one case that also contained a mutation at one of these sites.

FINDINGS

A number of previous studies have shown that DICER1 mutations are found in <1% of most cancers. To provide a more accurate estimate of the frequency of such mutations in TGCTs, we have analysed 96 TGCT samples using high resolution melting curve analysis for sequence variants in these four codons. Although we did not detect any mutations in any of these sites, we did identify a novel mutation (c.1725 R>Q) within the RNase IIIb domain in one TGCT sample, which was predicted to disturb DICER1 function.

CONCLUSION

Overall our findings suggest a mutation frequency in TGCTs of ~1%. We conclude therefore that hot-spot mutations, frequently seen in Sertoli-Leydig cell tumours, are not common in TGCTs.

The ter mutation in the rat Dnd1 gene initiates gonadal teratomas and infertility in both genders

A spontaneous mutation leading to the formation of congenital ovarian and testicular tumors was detected in the WKY/Ztm rat strain. The histological evaluation revealed derivatives from all three germ layers, thereby identifying these tumors as teratomas. Teratocarcinogenesis was accompanied by infertility and the underlying mutation was termed ter. Linkage analysis of 58 (WKY-ter×SPRD-Cu3) F2 rats associated the ter mutation with RNO18 (LOD = 3.25). Sequencing of candidate genes detected a point mutation in exon 4 of the dead-end homolog 1 gene (Dnd1), which introduces a premature stop codon assumed to cause a truncation of the Dnd1 protein. Genotyping of the recessive ter mutation revealed a complete penetrance of teratocarcinogenesis and infertility in homozygous ter rats of both genders. Morphologically non-tumorous testes of homozygous ter males were reduced in both size and weight. This testicular malformation was linked to a lack of spermatogenesis using immunohistochemical and histological staining. Our WKY-Dnd1(ter)/Ztm rat is a novel animal model to investigate gonadal teratocarcinogenesis and the molecular mechanisms involved in germ cell development of both genders.

Epigenetic signatures in stem cells and cancer stem cells

The physiological properties of pluripotency in stem cells and the processes of cell specialization are governed by epigenetic mechanisms, as they are inheritable but not dependent on the cell genotype. There is cumulating evidence demonstrating the presence of cells with stem cell properties within tumors, suggesting that these cells are responsible for tumor growth and heterogeneity. As epigenetic control of self-renewal and pluripotency is a hallmark of stem cells, there is increased interest in studying similar epigenetic mechanisms governing these stemness properties in cancer stem cells. Here we will review the evidence supporting a role for epigenetic mechanisms in the induction of cancer stem cells, with an emphasis on the epigenetic regulatory networks involved in the establishment of normal self-renewal and pluripotency, and their potential deregulation in cancer. We will also discuss the data supporting the plasticity of these mechanisms and its potential therapeutic implications.

A dual role of linker histone H1.4 Lys 34 acetylation in transcriptional activation

The linker histone H1 is a key player in chromatin organization, yet our understanding of the regulation of H1 functions by post-translational modifications is very limited. We provide here the first functional characterization of H1 acetylation. We show that H1.4K34 acetylation (H1.4K34ac) is mediated by GCN5 and is preferentially enriched at promoters of active genes, where it stimulates transcription by increasing H1 mobility and recruiting a general transcription factor. H1.4K34ac is dynamic during spermatogenesis and marks undifferentiated cells such as induced pluripotent stem (iPS) cells and testicular germ cell tumors. We propose a model for H1.4K34ac as a novel regulator of chromatin function with a dual role in transcriptional activation.

Epigenetic: a molecular link between testicular cancer and environmental exposures

In the last decades, studies in rodents have highlighted links between in utero and/or neonatal exposures to molecules that alter endocrine functions and the development of genital tract abnormalities, such as cryptorchidism, hypospadias, and impaired spermatogenesis. Most of these molecules, called endocrine disrupters exert estrogenic and/or antiandrogenic activities. These data led to the hypothesis of the testicular dysgenesis syndrome which postulates that these disorders are one clinical entity and are linked by epidemiological and pathophysiological relations. Furthermore, infertility has been stated as a risk factor for testicular cancer (TC). The incidence of TC has been increasing over the past decade. Most of testicular germ cell cancers develop through a pre-invasive carcinoma in situ from fetal germ cells (primordial germ cell or gonocyte). During their development, fetal germ cells undergo epigenetic modifications. Interestingly, several lines of evidence have shown that gene regulation through epigenetic mechanisms (DNA and histone modifications) plays an important role in normal development as well as in various diseases, including TC. Here we will review chromatin modifications which can affect testicular physiology leading to the development of TC; and highlight potential molecular pathways involved in these alterations in the context of environmental exposures.

Gonadal development and tumor formation at the crossroads of male and female sex determination

Malignant germ cell tumor (GCT) formation is a well-known complication in the management of patients with a disorder of sex development (DSD). DSDs are defined as congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. DSD patients in whom the karyotype - at least at the gonadal level - contains (a part of) the Y chromosome are at increased risk for neoplastic transformation of germ cells, leading to the development of the so-called 'type II germ cell tumors'. However, tumor risk in the various forms of DSD varies considerably between the different diagnostic groups. This contribution integrates our actual knowledge on the pathophysiology of tumor development in DSDs, recent findings on gonadal (mal)development in DSD patients, and possible correlations between the patient's phenotype and his/her risk for germ cell tumor development.

Clinical implications of stem cell gene Oct-4 expression in breast cancer

PURPOSE

To explore the expression of stem cell genes in breast cancer and the relationship between stem cell gene expression and clinical and pathological characteristics and prognosis of breast cancer.

BACKGROUND

By now, stem cell differentiation-related genes and the relationship between the genes and clinic-pathological characteristics and prognosis of breast cancer are still unclear.

MATERIALS AND METHODS

CD44+/CD24- tumor cells were selected by Flow cytometry. The differential expression of genes between CD44+/CD24- tumor cells and non-CD44+/CD24- tumor cells were detected by RT(2) Profiler™ PCR Array. The expression of stem cell gene Octamer-4 (Oct-4) was analyzed by immunohistochemistry staining and the relationship between Oct-4 and clinicopathological parameters of breast cancer was determined.

RESULTS

Seven different genes including stem cell differentiation-related factors (CD44, Oct-4, and nestin), cell cycle regulators (APC and CDC2), and growth factors (HGF and TGF) were detected as significantly differently expressed between CD44+/CD24- tumor cells and non-CD44+/CD24- tumor cells. Oct-4 protein expressed significantly higher in cancerous tissues than adjacent-tumor tissues (P = 0.001). Moreover, we observed that the expression of Oct-4 protein was related to histological type, lymph node status and molecular type of breast cancer (P = 0.001, 0.006, and 0.001, respectively). After survival analysis, the cases with highly expressed Oct-4 protein attained a significantly poorer postoperative disease-specific survival than those with none/low expressed Oct-4 protein (P = 0.001). In the Cox regression test, tumor size, histological type, disease stage, lymph node metastasis, Her-2 and Oct-4 were detected as the independent prognostic factors (P = 0.031, 0.012, 0.001, 0.002, 0.030, and 0.003, respectively).

CONCLUSIONS

Oct-4 was highly expressed in CD44+/CD24- tumor cells, and may be a potential biomarker for the initiation, progression, and differentiation of breast cancer.

Gonadal pathology and tumor risk in relation to clinical characteristics in patients with 45,X/46,XY mosaicism

CONTEXT

Gonadectomy is avoided whenever possible in boys with 45,X/46,XY. However, no clinical markers are currently available to guide clinicians in predicting gonadal tumor risk or hormone production.

OBJECTIVE

The objective of the study was to test the hypothesis that gonadal histology and risk for development of a malignant germ cell tumor are reflected by the clinical presentation of a 45,X/46,XY individual.

DESIGN

The design of the study was the correlation of clinical data [external masculinization score (EMS), pubertal outcome] with pathology data (gonadal phenotype, tumor risk).

SETTING

This was a multicenter study involving two multidisciplinary disorder of sex development teams.

PATIENTS

Patients included genetically proven 45,X/46,XY (and variants) cases, of whom at least one gonadal biopsy or gonadectomy specimen was available, together with clinical details.

INTERVENTIONS

Patients (n = 48) were divided into three groups, based on the EMS. Gonadal histology and tumor risk were assessed on paraffin-embedded samples (n = 87) by morphology and immunohistochemistry on the basis of established criteria.

MAIN OUTCOME MEASURES

Gonadal differentiation and tumor risk in the three clinical groups were measured. Clinical outcome in patients with at least one preserved gonad was also measured.

RESULTS

Tumor risk in the three groups was significantly related to the gonadal differentiation pattern (P < 0.001). In boys, hormone production was sufficient and was not predicted by the EMS.

CONCLUSIONS

The EMS reflects gonadal differentiation and tumor risk in patients with 45,X/46,XY. In boys, testosterone production is often sufficient, but strict follow-up is warranted because of malignancy risk, which appears inversely related to EMS. In girls, tumor risk is limited but gonads are not functional, making gonadectomy the most reasonable option.

Regenerating I messenger RNA and protein expression in the failing human testis: a potential molecular prognostic marker of seminoma

Infertility has been stated as a risk factor for testicular cancer; but currently, there is no prognostic indicator of tumor development from the pathologic testis with impaired spermatogenesis. Regenerating proteins are expressed in many human tissues including the testis, and their role in carcinogenesis has been well documented. In the present work, regenerating I messenger RNA and protein expression and cellular protein localization were studied in testicular biopsies of patients with normal (obstructive azoospermia) or impaired spermatogenesis (nonobstructive azoospermia) and in seminoma testis by quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunofluorescence analyses. No significant differences in regenerating I transcripts were reported between the 3 groups studied. However, regenerating I protein was highly expressed in pure seminoma and in placental-like alkaline phosphatase-positive seminiferous tubules with in situ carcinoma. Regenerating I protein levels measured by Western blotting increased from the placental-like alkaline phosphatase-negative distal region of the seminoma to the pure placental-like alkaline phosphatase-positive tumoral region. Importantly, although cells localized in seminiferous tubules of obstructive azoospermic patients with normal spermatogenesis were very slightly labeled, persisting germ, Sertoli, and myoid cells and fibrous tissues were strongly regenerating I positive in seminiferous tubules of nonobstructive azoospermia. These results suggest the possibility to use regenerating I as a prognostic marker of tumoral development in the infertile testis.

Embryonic Stem Cell Transplantation into Seminiferous Tubules: A Model for the Study of Invasive Germ Cell Tumors of the Testis

Over the last 15 years, cell transplantation into seminiferous tubules has become a valuable tool to study germinal cell biology and related matters. This is particularly so, because the blood–testis permeability barrier establishes a sealed compartment which protect against certain influences such as immunological rejection. In the light of the functional and genetic similarities between carcinoma in situ (CIS) of the testis and embryonic stem (ES) cells, our laboratory has developed a tumor assay to study cancer invasion processes in testicular germ cell tumors (TGCT) based on the transplantation of ES cells into the seminiferous tubules. Here, we describe this new tumor assay and provide additional information regarding the transplantation techniques used and their application for the study of TGCTs. Finally, we discuss the practical implications of our experimental approach and its potential application for the understanding of TGCT invasive processes and the development of new antineoplastic strategies.

Zebrafish models of germ cell tumor

Germ cell tumors are neoplasms arising from pluripotent germ cells. In humans, these tumors occur in infants, children and young adults. The tumors display a wide range of histologic differentiation states which exhibit different clinical behaviors. Information about the molecular basis of germ cell tumors, and representative animal models of these neoplasms, are lacking. Germline development in zebrafish and humans is broadly conserved, making the fish a useful model to probe the connections between germ cell development and tumorigenesis. Here, we provide an overview of germline development and a brief review of germ cell tumor biology in humans and zebrafish. We also outline some methods for studying the zebrafish germline.

APAF-1 is related to an undifferentiated state in the testicular germ cell tumor pathway

Apoptotic protease activating factor-1 (APAF-1) is a key regulator gene of apoptosis, located downstream from p53. Loss of APAF-1 expression is associated with chemorefractory malignant melanoma and neuronal cell differentiation. In order to make clear the function of APAF-1 in the carcinogenesis of germ cell tumors, we evaluated the expression levels of APAF-1 and several apoptosis and differentiation markers by immunohistochemistry in formalin-fixed paraffin-embedded samples from 43 cases of testicular germ cell tumor (TGCT) and six specimens of normal testis tissue. Expression of cleaved caspase-3, Oct-3/4, and Ki-67 were also examined by immunohistochemistry to evaluate apoptotic reactivity, tumor differentiation, and proliferation activity, respectively. APAF-1 was downregulated in two TGCT cell lines by siRNA transfection, and subsequent expression of the Ki-67 and Oct-3/4 genes and differentiation markers of three embryonic germ layers including keratin16 (KRT16) for ectoderm, vimentin (VIM) for mesoderm and GATA4 for endoderm were then tested. No significant relationship was found between APAF-1 expression and apoptotic activity in TGCTs. Expression of APAF-1, Oct-3/4, and Ki-67 was significantly higher in seminomas than in non-seminomas. In TGCTs, higher APAF-1 expression was correlated with higher proliferation (high Ki-67) and a lower degree of differentiation (high Oct-3/4). Interestingly, the expression of APAF-1 gradually decreased in accordance with tumor differentiation (seminoma and embryonal carcinoma > teratoma). Downregulation of APAF-1 in TGCT cell lines resulted in a decrease of Ki-67 and Oct-3/4 and an increase of VIM and KRT16 gene expression. These data show that higher expression of APAF-1 is related to an undifferentiated state in the TGCT pathway.

Gonadal tumours and DSD

Disorders of sex development (DSD), previously referred to as intersex, has been recognised as one of the main risk factors for development of type II germ cell tumours (GCTs), that is, seminomas/dysgerminomas and non-seminomas (e.g., embryonal carcinoma, yolk sac tumour, choriocarcinoma and teratoma). Within the testis, this type of cancer is the most frequent malignancy in adolescent and young adult Caucasian males. Although these males are not known to have dysgenetic gonads, the similarities in the resulting tumours suggest a common aetiological mechanism(s),--genetically, environmentally or a combination of both. Within the group of DSD patients, being in fact congenital conditions, the risk of malignant transformation of germ cells is highly heterogeneous, depending on a number of parameters, some of which have only recently been identified. Understanding of these recent insights will stimulate further research, with the final aim to develop an informative clinical decision tree for DSD patients, which includes optimal (early) diagnosis without overtreatment, such as prophylactic gonadectomy in the case of a low tumour risk.

The quiet revolution: Disorders of sex development

The approach to the management of disorders of sex development (DSD) has undergone major changes in recent years. The catalyst has been a revised nomenclature, new classification of the causes of DSD and a willingness for health professionals to work in a multi-disciplinary format. In a remarkably short length of time, these revolutionary changes are becoming accepted practice across a range of medical and scientific disciplines.

GOLPH2 expression may serve as diagnostic marker in seminomas

BACKGROUND

GOLPH2 (Golgi phosphoprotein 2) is a novel Golgi membrane protein. Despite its unknown physiologic function, however, it has been proposed as a biomarker for hepatocellular and prostate carcinoma due to its upregulation in those cancer entities. Whether the overexpression of GOLPH2 is tumour specific or a generic parameter of malignancy and whether this finding is true for additional carcinomas has not been determined. In this study, we aimed to evaluate the expression pattern of GOLPH2 in testicular seminomas, the most common histologic subtype of testicular neoplasm.

METHODS

GOLPH2 protein expression was assessed by immunohistochemistry in 69 testicular seminomas and compared to the expression rates in matching normal testicular tissue and intratubular germ cell neoplasia of unclassified type (IGCNU). In addition, a subset of Leydig cell tumours was analyzed accordingly.

RESULTS

GOLPH2 was consistently overexpressed (89.9%) in seminomas. Matching non-neoplastic tissue showed weak or negative staining. The observed differences between non-neoplastic and neoplastic tissue were statistically highly significant (p < 0.001). There were no significant associations with tumour status. Interestingly, GOLPH2 was also highly expressed in the intertubular Leydig cells as well as in Leydig cell tumours.

CONCLUSIONS

GOLPH2 protein is highly expressed in seminomas and in Leydig cell tumours. This study fosters the association of GOLPH2 with malignant neoplastic processes. The staining pattern is easily assessable and consistent which is a favourable property especially in clinical settings. GOLPH2 could be a novel immunohistochemical marker for the assessment of testicular neoplasms, especially against the background that in analogy to hepatocellular carcinomas complementary GOLPH2 serum levels might be helpful in detecting metastases or recurrent tumour. Therefore serum studies and analyses of GOLPH2 expression in non-seminomatous germ cell tumours are strongly warranted.

Molecular and cell biology of testicular germ cell tumors

Although testicular germ cell tumors (TGCTs) are relatively uncommon, they are particularly important as they tend to affect children and young men, representing the most common tumor in male aged from 20 to 40years. TGCTs are a heterogeneous group of tumors, with specific peculiarities reflecting on epidemiologic distribution and clinic-pathological features. TGCTs show a high-cure rates in both seminomas and nonseminomas and represent the model of a curable neoplasia: sensitive serum tumor markers, accurate prognostic classification, contribute to a high effectiveness of cancer therapy. However, up to 30% of patients diagnosed with metastatic nonseminomas do not achieve a durable remission, and in metastatic teratomas cisplatin-based treatment resistance has been observed. These different prognostic and therapeutic features of TGCTs highlight the need for a better understanding of the molecular biology of TGCT, that could help to improve disease management and to tailor aggressiveness of treatment to the severity of the prognosis.