Role of SPRY4 in health and disease

SPRY4 is a protein encoding gene that belongs to the Spry family. It inhibits the mitogen-activated protein kinase (MAPK) signaling pathway and plays a role in various biological functions under normal and pathological conditions. The SPRY4 protein has a specific structure and interacts with other molecules to regulate cellular behavior. It serves as a negative feedback inhibitor of the receptor protein tyrosine kinases (RTK) signaling pathway and interferes with cell proliferation and migration. SPRY4 also influences inflammation, oxidative stress, and cell apoptosis. In different types of tumors, SPRY4 can act as a tumor suppressor or an oncogene. Its dysregulation is associated with the development and progression of various cancers, including colorectal cancer, glioblastoma, hepatocellular carcinoma, perihilar cholangiocarcinoma, gastric cancer, breast cancer, and lung cancer. SPRY4 is also involved in organ development and is associated with ischemic diseases. Further research is ongoing to understand the expression and function of SPRY4 in specific tumor microenvironments and its potential as a therapeutic target.

DMRT1 regulates human germline commitment

Germline commitment following primordial germ cell (PGC) specification during early human development establishes an epigenetic programme and competence for gametogenesis. Here we follow the progression of nascent PGC-like cells derived from human embryonic stem cells in vitro. We show that switching from BMP signalling for PGC specification to Activin A and retinoic acid resulted in DMRT1 and CDH5 expression, the indicators of migratory PGCs in vivo. Moreover, the induction of DMRT1 and SOX17 in PGC-like cells promoted epigenetic resetting with striking global enrichment of 5-hydroxymethylcytosine and locus-specific loss of 5-methylcytosine at DMRT1 binding sites and the expression of DAZL representing DNA methylation-sensitive genes, a hallmark of the germline commitment programme. We provide insight into the unique role of DMRT1 in germline development for advances in human germ cell biology and in vitro gametogenesis.

Testicular germ cell tumors: Genomic alternations and RAS-dependent signaling

Testicular germ cell tumors (TGCTs) are a common malignancy occurring in young adult men. The various genetic risk factors have been suggested to contribute to TGCT pathogenesis, however, they have a distinct mutational profile with a low rate of somatic point mutations, more frequent chromosomal gains, and aneuploidy. The most frequently mutated oncogenes in human cancers are RAS oncogenes, while their impact on testicular carcinogenesis and refractory disease is still poorly understood. In this mini-review, we summarize current knowledge on genetic alternations of RAS signaling-associated genes (the single nucleotide polymorphisms and point mutations) in this particular cancer type and highlight their link to chemotherapy resistance mechanisms. We also mention the impact of epigenetic changes on TGCT progression. Lastly, we propose a model for RAS-dependent signaling networks, regulation, cross-talks, and outcomes in TGCTs.

Sacrococcygeal Teratoma : A Tumor at the Center of Embryogenesis

Sacrococcygeal teratoma (SCT) is an extragonadal germ cell tumor (GCT) that develops in the fetal and neonatal periods. SCT is a type I GCT in which only teratoma and yolk sac tumors arise from extragonadal sites. SCT is the most common type I GCT and is believed to originate through epigenetic reprogramming of early primordial germ cells migrating from the yolk sac to the gonadal ridges. Fetal SCT diagnosed in utero presents many obstetrical problems. For high-risk fetuses, fetal interventions (devascularization and debulking) are under development. Most patients with SCT are operated on after birth. Complete surgical resection is the key for tumor control, and the anatomical location of the tumor determines the surgical approaches. Incomplete resection and malignant histology are risk factors for recurrence. Approximately 10-15% of patients have a tumor recurrence, which is frequently of malignant histology. Long-term surveillance with monitoring of serum alpha fetoprotein and magnetic resonance imaging is required. Survivors of SCT may suffer anorectal, urological, and sexual sequelae later in their life, and comprehensive evaluation and care are required.

Germ cell determination and the developmental origin of germ cell tumors

In each generation, the germline is tasked with producing somatic lineages that form the body, and segregating a population of cells for gametogenesis. During animal development, when do cells of the germline irreversibly commit to producing gametes? Integrating findings from diverse species, we conclude that the final commitment of the germline to gametogenesis - the process of germ cell determination - occurs after primordial germ cells (PGCs) colonize the gonads. Combining this understanding with medical findings, we present a model whereby germ cell tumors arise from cells that failed to undertake germ cell determination, regardless of their having colonized the gonads. We propose that the diversity of cell types present in these tumors reflects the broad developmental potential of migratory PGCs.

Neonatal Malignant Disorders: Germ Cell Tumors

Germ cell tumors (GCTs) comprise a wide spectrum of benign and malignant tumors. Neonatal GCTs are predominantly teratomas (mature or immature), which are typically cured with surgery alone. Relapses are infrequent even in the setting of microscopic residual disease; therefore, negative surgical margins at the cost of significant morbidity are not recommended. In neonates with metastatic malignant disease or malignant disease for which upfront surgical resection is not feasible without significant morbidity, an initial biopsy followed by neoadjuvant chemotherapy and delayed surgical resection is recommended. Carboplatin-based regimens should be considered when chemotherapy is indicated.

Female Germ Cell Development, Functioning and Associated Adversities under Unfavorable Circumstances

In the present era, infertility is one of the major issues which restricts many couples to have their own children. Infertility is the inability to achieve a clinical pregnancy after regular unprotected sexual intercourse for the period of one year or more. Various factors including defective male or female germ cell development, unhealthy and improper lifestyles, diseases like cancer and associated chemo-or-radiation therapies, congenital disorders, etc., may be responsible for infertility. Therefore, it is highly important to understand the basic concepts of germ cell development including primordial germ cell (PGC) formation, specification, migration, entry to genital ridges and their molecular mechanisms, activated pathways, paracrine and autocrine signaling, along with possible alteration which can hamper germ cell development and can cause adversities like cancer progression and infertility. Knowing all these aspects in a proper way can be very much helpful in improving our understanding about gametogenesis and finding possible ways to cure related disorders. Here in this review, various aspects of gametogenesis especially female gametes and relevant factors causing functional impairment have been thoroughly discussed.

Germ Cell Tumors in Adolescents and Young Adults

Germ cell tumors (GCTs) are rare in childhood, representing only 3.5% of childhood cancers, but a common malignancy in adolescents and young adults (AYAs), accounting for 13.9% of neoplasms in adolescents between age 15 and 19 years. The overall outcomes of patients treated for GCTs are excellent. However, as seen in other cancers, outcomes for AYA patients are significantly worse. Understanding the reasons for this observation has led to different approaches to diagnosis, staging, and treatment. The Malignant Germ Cell International Consortium was created to bring together pediatric, gynecologic, and testicular cancer specialists to promote research initiatives and provide evidence-based approaches in the management of GCTs across different age groups. Collaboration between multiple subspecialties is essential to further understand the disease continuum, the underlying biologic characteristics, and the development of appropriate therapeutic approaches. This review focuses on the unique characteristics of patients with extracranial GCTs in the AYA group.

Report From the International Society of Urological Pathology (ISUP) Consultation Conference on Molecular Pathology of Urogenital Cancers: IV: Current and Future Utilization of Molecular-Genetic Tests for Testicular Germ Cell Tumors

The International Society of Urological Pathology (ISUP) organized a Consultation Conference in March 2019 dealing with applications of molecular pathology in Urogenital Pathology, including testicular tumors (with a focus on germ cell tumors [GCTs]), preceded by a survey among its members to get insight into current practices in testicular germ cell tumor (TGCT) diagnostics and adoption of the ISUP immunohistochemical guidelines published in 2014. On the basis of the premeeting survey, the most commonly used immunomarker panel includes OCT3/4, placental alkaline phosphate, D2-40, SALL4, CD117, and CD30 for GCTs and the documentation of germ cell neoplasia in situ (GCNIS). Molecular testing, specifically 12p copy gain, is informative to distinguish non-GCNIS versus GCNIS related GCTs, and establishing germ cell origin of tumors both in the context of primary and metastatic lesions. Other molecular methodologies currently available but not widely utilized for TGCTs include genome-wide and targeted approaches for specific genetic anomalies, P53 mutations, genomic MDM2 amplification, and detection of the p53 inactivating miR-371a-3p. The latter also holds promise as a serum marker for malignant TGCTs. This manuscript provides an update on the classification of TGCTs, and describes the current and future role of molecular-genetic testing. The following recommendations are made: (1) Presence of GCNIS should be documented in all cases along with extent of spermatogenesis; (2) Immunohistochemical staining is optional in the following scenarios: identification of GCNIS, distinguishing embryonal carcinoma from seminoma, confirming presence of yolk sac tumor and/or choriocarcinoma, and differentiating spermatocytic tumor from potential mimics; (3) Detection of gain of the short arm of chromosome 12 is diagnostic to differentiate between non-GCNIS versus GCNIS related GCTs and supportive to the germ cell origin of both primary and metastatic tumors.

Association Between BAK1 Gene rs210138 Polymorphisms and Testicular Germ Cell Tumors: A Systematic Review and Meta-Analysis

Background: Several studies including some genome-wide association studies (GWAS) had shown that BAK1 gene rs210138 polymorphisms might be associated with testicular germ cell tumors (TGCT). Here we tried to sum up the association through a systematic review and meta-analysis. Methods: Studies associated with BAK1 rs210138 and TGCT was systematically searched in databases. The effect size was pooled according to ORs and 95% CIs. Results: Our systematic review and meta-analysis comprised 14 articles. Significantly increased risk of TGCT was found in eligible GWAS and follow-up studies, in overall group and its Caucasian subgroup. Conclusions: Compared with adenine (A), BAK1 rs210138 guanine (G) is associated with increased risk of TGCT. Well-planned studies with larger sample size and more subgroups are needed to verify the risk identified in our systematic review and meta-analysis.

Association between KITLG Gene Polymorphisms and Testicular Germ Cell Tumors: A Systematic Review and Meta-analysis

It has been reported that c-KIT ligand (KITLG) gene polymorphisms may be associated with testicular germ cell tumors (TGCT). Owing to mixed and inconclusive results, we conducted a systematic review and meta-analysis to summarize and clarify this association. A systematic search of studies on the association between KITLG gene polymorphisms and TGCT susceptibility was conducted in databases. Odds ratios and 95% confidence intervals were used to pool the effect size. Six articles were included in our systematic review and meta-analysis. Compared with adenine (A), KITLG rs995030 guanine (G) might be associated with increased risk of TGCT. There are insufficient data to fully confirm the association between KITLG rs4474514 and TGCT susceptibility. Well-designed studies with larger sample size and more subgroups are required to validate the risk identified in the current meta-analysis.

Predicting Gonadal Germ Cell Cancer in People with Disorders of Sex Development; Insights from Developmental Biology

The risk of gonadal germ cell cancer (GGCC) is increased in selective subgroups, amongst others, defined patients with disorders of sex development (DSD). The increased risk is due to the presence of part of the Y chromosome, i.e., GonadoBlastoma on Y chromosome GBY region, as well as anatomical localization and degree of testicularization and maturation of the gonad. The latter specifically relates to the germ cells present being at risk when blocked in an embryonic stage of development. GGCC originates from either germ cell neoplasia in situ (testicular environment) or gonadoblastoma (ovarian-like environment). These precursors are characterized by presence of the markers OCT3/4 (POU5F1), SOX17, NANOG, as well as TSPY, and cKIT and its ligand KITLG. One of the aims is to stratify individuals with an increased risk based on other parameters than histological investigation of a gonadal biopsy. These might include evaluation of defined susceptibility alleles, as identified by Genome Wide Association Studies, and detailed evaluation of the molecular mechanism underlying the DSD in the individual patient, combined with DNA, mRNA, and microRNA profiling of liquid biopsies. This review will discuss the current opportunities as well as limitations of available knowledge in the context of predicting the risk of GGCC in individual patients.

Human germ cell tumours from a developmental perspective

Human germ cell tumours (GCTs) are derived from stem cells of the early embryo and the germ line. They occur in the gonads (ovaries and testes) and also in extragonadal sites, where migrating primordial germ cells are located during embryogenesis. This group of heterogeneous neoplasms is unique in that their developmental potential is in effect determined by the latent potency state of their cells of origin, which are reprogrammed to omnipotent, totipotent or pluripotent stem cells. Seven GCT types, defined according to their developmental potential, have been identified, each with distinct epidemiological and (epi)genomic features. Heritable predisposition factors affecting the cells of origin and their niches likely explain bilateral, multiple and familial occurrences of the different types of GCTs. Unlike most other tumour types, GCTs are rarely caused by somatic driver mutations, but arise through failure to control the latent developmental potential of their cells of origin, resulting in their reprogramming. Consistent with their non-mutational origin, even the malignant tumours of the group are characterized by wild-type TP53 and high sensitivity for DNA damage. However, tumour progression and the rare occurrence of treatment resistance are driven by embryonic epigenetic state, specific (sub)chromosomal imbalances and somatic mutations. Thus, recent progress in understanding GCT biology supports a comprehensive developmental pathogenetic model for the origin of all GCTs, and provides new biomarkers, as well as potential targets for treatment of resistant disease.

Identification and comparative profiling of gonadal microRNAs in the adult pigeon (Columba livia)

1. MicroRNAs are small noncoding RNA molecules that play crucial roles in gene expression. However, the comparative profiling of testicular and ovarian microRNAs in birds are rarely reported, particularly in pigeon.2. In this study, Illumina next-generation sequencing technology was used to sequence miRNA libraries of the gonads from six healthy adult utility pigeons. A total of 344 conserved known miRNAs and 32 novel putative miRNAs candidates were detected. Compared with those of ovaries, 130 differentially expressed (DE) miRNAs were identified in the testes. Among them, 70 miRNAs showed down-regulation in the ovaries, while another 60 miRNAs were up-regulated.3. Combining the results of the expression of target gene measurements and pathway enrichment analyses, it was revealed that some DEmiRNAs from the gonad samples involved in sexual differentiation and development (such as cli-miR-210-3p and cli-miR-214-3p) could down-regulate AR (androgen receptor). Cli-miR-181b-5p, cli-miR-9622-3p and cli-miR-145-5p were highly expressed in both the ovaries and testes, which could co-target HOXC9, and were related to regulation of primary metabolic processes. KEGG enrichment analysis showed that DEmiRNAs may play biological and sex-related roles in pigeon gonads.4. The expression profiles of testicular and ovarian miRNA in adult pigeon gonads are presented for the first time, and the findings may contribute to a better understanding of gonadal expression in poultry.

Global incidence comparisons and trends in ovarian germ cell tumors by geographic region in girls, adolescents and young women: 1988-2012

OBJECTIVE

Ovarian germ cell tumors (OGCT) are the primary ovarian malignancy affecting girls and young women. Globally, incidence rates and trends for OGCTs have not been compared in the literature and their etiology is not well described. Comparisons of incidence globally could inform etiologic hypotheses. The aim of this analysis was to evaluate geographic variation in OGCT incidence and to identify trends in incidence rates.

METHODS

Data were extracted from Cancer Incidence in 5 Continents (CI5) from 1988 to 2012. Rates of OGCT in women and girls were calculated for ages 0-9, 10-19, and 20-39 years and standardized to the 2000-2025 average world population. Data were aggregated within subregions corresponding to the United Nations Statistics Division (UNSD) geoscheme. Incidence rates were compared in subregions and average annual percent change (AAPC) was estimated using Poisson regression.

RESULTS

Overall, the highest incidence rates were observed in 10-19-year-olds. Incidence was generally the highest in Eastern Asia, Central America and North America. While incidence was variable by geographic region, less variation was observed in 0-9-year-olds as compared to adolescents and young adults. Significant increases in incidence were seen in some regions (Eastern Asia, Oceania, Western Europe, Southern Europe, and North America) and in countries with a high or very high human development index for one or more age groups.

CONCLUSIONS

Evaluating 25 years of OGCT incidence data, the highest incidence rates and largest increases in incidence were seen in Eastern Asia. Future studies should focus on etiologic features that may account for geographic variation and increases in incidence of OGCT.

Isolation and molecular characterization of spermatogonia from male Sprague-Dawley rats exposed in utero and postnatally to dibutyl phthalate or acrylamide

The increased incidence of testicular disorders in young men and the possible influence of environmental chemicals, such as dibutyl phthalate (DBP) and acrylamide (AA), requires experimental models for identifying modes of action. Most published reproductive toxicologic studies use RNA samples from the total testis to evaluate testicular gene expression; however, analyses of isolated cell types could provide a more specific tool. Among testicular germ cells, spermatogonia are critical since they represent the onset of spermatogenesis. This study aimed, (1) to establish a technique for spermatogonia isolation; (2) to apply this isolation technique to verify possible gene expression alterations (Pou5f1, Kitlg, Mki-67, Bak1 and Spry4) in prepubertal post-natal day, (PND24) and pubertal (PND45) testes after in utero and postnatal exposure to DBP or AA. The technique was efficient for isolation of a majority of spermatogonia. In utero DBP exposure led to reduced litter body weight at birth, reduced anogenital distance of male pups on PND4, and increased frequency of male nipple retention on PND14 compared to controls. DBP-exposed relative testes weights were reduced only at PND24 compared to control but they did not differ at PND45. DBP-exposed animals showed reduced expression levels of Pou5f1 and Mki67 on PND24, and reduced expression of Pou5f1 and Spry4 on PND45. AA exposure reduced expression of Pou5f1, Mki67, and Spry4 at PND45 although not significantly. Our results suggest that DBP acts by reducing cell proliferation and impairing differentiation in prepubertal and pubertal testes.

EGF Receptor and mTORC1 Are Novel Therapeutic Targets in Nonseminomatous Germ Cell Tumors

Germ cell tumors (GCT) are malignant tumors that arise from pluripotent embryonic germ cells and occur in children and young adults. GCTs are treated with cisplatin-based regimens which, while overall effective, fail to cure all patients and cause significant adverse late effects. The seminoma and nonseminoma forms of GCT exhibit distinct differentiation states, clinical behavior, and response to treatment; however, the molecular mechanisms of GCT differentiation are not fully understood. We tested whether the activity of the mTORC1 and MAPK pathways were differentially active in the two classes of GCT. Here we show that nonseminomatous germ cell tumors (NSGCT, including embryonal carcinoma, yolk sac tumor, and choriocarcinoma) from both children and adults display activation of the mTORC1 pathway, while seminomas do not. In seminomas, high levels of REDD1 may negatively regulate mTORC1 activity. In NSGCTs, on the other hand, EGF and FGF2 ligands can stimulate mTORC1 and MAPK signaling, and members of the EGF and FGF receptor families are more highly expressed. Finally, proliferation of NSGCT cells in vitro and in vivo is significantly inhibited by combined treatment with the clinically available agents erlotinib and rapamycin, which target EGFR and mTORC1 signaling, respectively. These results provide an understanding of the signaling network that drives GCT growth and a rationale for therapeutic targeting of GCTs with agents that antagonize the EGFR and mTORC1 pathways. Mol Cancer Ther; 17(5); 1079-89. ©2018 AACR.

Pediatric Germ Cell Tumors: A Developmental Perspective

Germ cell tumors (GCTs) arising in infants, children, and adolescents present a set of special challenges. GCTs make up about 3% of malignancies in children aged 0–18 and nearly 15% of cancers in adolescents. Epidemiologic and molecular evidence suggests that GCTs in young children likely represent a distinct biologic group as compared to GCTs of older adolescents and adults. Despite this difference, pediatric GCTs are typically treated with cisplatin-based multiagent regimens similar to those used in adults. There is evidence that children are particularly vulnerable to late effects of conventional therapy, including ototoxicity, pulmonary abnormalities, and secondary malignancies, motivating the search for molecular targets for novel therapies. Evidence is accumulating that the genes and mechanisms controlling normal germ cell development are particularly relevant to the understanding of germ cell tumorigenesis. Perturbations in the epigenetic program of germ cell differentiation, with resulting effects on the regulation of pluripotency, may contribute to the marked histologic variability of GCTs. Perturbations in the KIT receptor signaling pathway have been identified via next-generation sequencing studies and in genome-wide association studies of testicular cancer susceptibility. Here, we review these and other biological insights that may fuel further translational and clinical research in childhood GCTs.

Current knowledge of risk factors for testicular germ cell tumors

The development of the human gonads is tightly regulated by the correct sequential expression of many genes and hormonal activity. Disturbance of this regulation does not only prevent proper development of the gonads, but it also contributes to the development of testicular germ cell tumors. Recent genetic studies, especially genome-wide association studies, have made great progress in understanding genetic susceptibility. Although there is strong evidence of inherited risks, many environmental factors also contribute to the development of testicular germ cell tumors. Histopathological studies have shown that most testicular germ cell tumors arise from germ cell neoplasia in situ, which is thought to be arrested and transformed primordial germ cells. Seminoma has features identical to germ cell neoplasia in situ or primordial germ cells, whereas non-seminoma shows varied differentiation. Seminomas and embryonic cell carcinomas have the feature of pluripotency, which is thought to be the cause of histological heterogeneity and mixed pathology in testicular germ cell tumors. Testicular germ cell tumors show high sensitivity to chemotherapies, but 20-30% of patients show resistance to standard chemotherapy. In the present review, the current knowledge of the epidemiological and genomic factors for the development of testicular germ cell tumors is reviewed, and the mechanisms of resistance to chemotherapies are briefly mentioned.

Tumorigenic proteins upregulated in the MYCN-amplified IMR-32 human neuroblastoma cells promote proliferation and migration

Childhood neuroblastoma is one of the most common types of extra-cranial cancer affecting children with a clinical spectrum ranging from spontaneous regression to malignant and fatal progression. In order to improve the clinical outcomes of children with high-risk neuroblastoma, it is crucial to understand the tumorigenic mechanisms that govern its malignant behaviors. MYCN proto-oncogene, bHLH transcription factor (MYCN) amplification has been implicated in the malignant, treatment-evasive nature of aggressive, high-risk neuroblastoma. In this study, we used a SILAC approach to compare the proteomic signatures of MYCN-amplified IMR-32 and non-MYCN-amplified SK-N-SH human neuroblastoma cells. Tumorigenic proteins, including fatty-acid binding protein 5 (FABP5), L1-cell adhesion molecule (L1-CAM), baculoviral IAP repeat containing 5 [BIRC5 (survivin)] and high mobility group protein A1 (HMGA1) were found to be significantly upregulated in the IMR-32 compared to the SK-N-SH cells and mapped to highly tumorigenic pathways including, MYC, MYCN, microtubule associated protein Tau (MAPT), E2F transcription factor 1 (E2F1), sterol regulatory element binding transcription factor 1 or 2 (SREBF1/2), hypoxia-inducible factor 1α (HIF-1α), Sp1 transcription factor (SP1) and amyloid precursor protein (APP). The transcriptional knockdown (KD) of MYCN, HMGA1, FABP5 and L1-CAM significantly abrogated the proliferation of the IMR-32 cells at 48 h post transfection. The early apoptotic rates were significantly higher in the IMR-32 cells in which FABP5 and MYCN were knocked down, whereas cellular migration was significantly abrogated with FABP5 and HMGA1 KD compared to the controls. Of note, L1-CAM, HMGA1 and FABP5 KD concomitantly downregulated MYCN protein expression and MYCN KD concomitantly downregulated L1-CAM, HMGA1 and FABP5 protein expression, while survivin protein expression was significantly downregulated by MYCN, HMGA1 and FABP5 KD. In addition, combined L1-CAM and FABP5 KD led to the concomitant downregulation of HMGA1 protein expression. On the whole, our data indicate that this inter-play between MYCN and the highly tumorigenic proteins which are upregulated in the malignant IMR-32 cells may be fueling their aggressive behavior, thereby signifying the importance of combination, multi-modality targeted therapy to eradicate this deadly childhood cancer.

Germ cell tumors: Insights from the Drosophila ovary and the mouse testis

Ovarian and testicular germ cell tumors of young adults are thought to arise from defects in germ cell development, but the molecular mechanisms underlying malignant transformation are poorly understood. In this review, we focus on the biology of germ cell tumor formation in the Drosophila ovary and the mouse testis, for which evidence supports common underlying mechanisms, such as blocking initiation into the differentiation pathway, impaired lineage progression, and sexual identity instability. We then discuss how these concepts inform our understanding of the disease in humans. Mol. Reprod. Dev. 84: 200-211, 2017. © 2017 Wiley Periodicals, Inc.

Exploring the molecular aspects associated with testicular germ cell tumors: a review

Testicular germ cell tumors (TGCTs) represent the most common solid tumors affecting young men. They constitute a distinct entity because of their embryonic origin and their unique biological behavior. Recent preclinical data regarding biological signaling machinery as well as genetic and epigenetic mechanisms associated with molecular patterns of tumors have contribute to explain the pathogenesis and the differentiation of TGCTs and to understand the mechanisms responsible for the development of resistance to treatment. In this review, we discuss the main genetic and epigenetic events associated with TGCTs development in order to better define their role in the pathogenesis of these tumors and in cisplatin-acquired resistance.

Variants in BAK1, SPRY4, and GAB2 are associated with pediatric germ cell tumors: A report from the children's oncology group

Germ cell tumors (GCT) are a rare form of childhood cancer that originate from the primordial germ cell. Recent genome-wide association studies (GWAS) have identified susceptibility alleles for adult testicular GCT (TGCT). We test whether these SNPs are associated with GCT in pediatric and adolescent populations. This case-parent triad study includes individuals with GCT diagnosed between ages 0 and 19. We evaluated 26 SNPs from GWAS of adult TGCT and estimated main effects for pediatric GCT within complete trios (N = 366) using the transmission disequilibrium test. We used Estimation of Maternal, Imprinting and interaction effects using Multinomial modelling to evaluate maternal effects in non-Hispanic white trios and dyads (N = 244). We accounted for multiple comparisons using a Bonferroni correction. A variant in SPRY4 (rs4624820) was associated with reduced risk of GCT (OR [95% CI]: 0.70 [0.57, 0.86]). A variant in BAK1 (rs210138) was positively associated with GCT (OR [95% CI]: 1.70 [1.32, 2.18]), with a strong estimated effect for testis tumors (OR [95% CI]: 3.31 [1.89, 5.79]). Finally, a SNP in GAB2 (rs948662) was associated with increased risk for GCT (OR [95% CI]: 1.56 [1.20, 2.03]). Nominal associations (P < 0.05) were noted for eight additional loci. A maternal effect was observed for KITLG SNP rs4474514 (OR [95% CI]: 1.66 [1.21, 2.28]) and a paternal parent-of-origin effect was observed for rs7221274 (P = 0.00007), near TEX14, RAD51C, and PPM1E. We observed associations between SNPs in SPRY4, BAK1, and GAB2 and GCTs. This analysis suggests there may be common genetic risk factors for GCT in all age groups.

Risk of second gonadal cancers in women and children with germ cell tumors

BACKGROUND

Men with testicular cancer have an increased risk of developing cancer in the contralateral testis, but the risks of second gonadal cancers (SGCs) in women and children treated for germ cell tumors (GCTs) have not previously been quantified.

METHODS

The incidence of SGCs was ascertained in patients who had survived for at least 1 year after GCT diagnosis using data from the Surveillance, Epidemiology, and End Results SEER 9 registries (1980-2012). Relative risks of SGCs were estimated separately for boys, women, and girls compared with men based on Poisson regression analysis.

RESULTS

The cohort included 21,546 individuals (1116 boys, 827 women, 622 girls, and 18,981 men). A total of 25 SGCs were identified in boys, 1 in women, and 2 in girls compared with 254 in men. The risk of SGC in postpubertal boys (aged ≥10 years) was comparable to that of adult men (boys: standardized incidence ratio, 15.90; 95% confidence interval, 10.29-23.47; men: standardized incidence ratio, 10.88; 95% confidence interval, 9.58-12.30). However, no SGCs were observed in boys who were diagnosed with a testicular GCT before age 10 years (N = 179). An elevated risk of SGC was also not observed for women or girls.

CONCLUSIONS

The apparent lack of an SGC in prepubertal boys suggests that susceptibility is either age-dependent and/or histology-dependent. The sex differences in the risk of SGC suggest differences in the etiology of ovarian versus testicular GCT. The finding that the risk of SGCs in postpubertal boys is similar to that observed in men indicates that long-term follow-up for SGC is warranted in postpubertal boys. Cancer 2016;122:2076-82. © 2016 American Cancer Society.

Paediatric extracranial germ-cell tumours

Management of paediatric extracranial germ-cell tumours carries a unique set of challenges. Germ-cell tumours are a heterogeneous group of neoplasms that present across a wide age range and vary in site, histology, and clinical behaviour. Patients with germ-cell tumours are managed by a diverse array of specialists. Thus, staging, risk stratification, and treatment approaches for germ-cell tumours have evolved disparately along several trajectories. Paediatric germ-cell tumours differ from the adolescent and adult disease in many ways, leading to complexities in applying age-appropriate, evidence-based care. Suboptimal outcomes remain for several groups of patients, including adolescents, and patients with extragonadal tumours, high tumour markers at diagnosis, or platinum-resistant disease. Survivors have significant long-term toxicities. The challenge moving forward will be to translate new insights from molecular studies and collaborative clinical data into improved patient outcomes. Future trials will be characterised by improved risk-stratification systems, biomarkers for response and toxic effects, rational reduction of therapy for low-risk patients and novel approaches for poor-risk patients, and improved international collaboration across paediatric and adult cooperative research groups.

Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility

It is predicted that Japan and European Union will soon experience appreciable decreases in their populations due to persistently low total fertility rates (TFR) below replacement level (2.1 child per woman). In the United States, where TFR has also declined, there are ethnic differences. Caucasians have rates below replacement, while TFRs among African-Americans and Hispanics are higher. We review possible links between TFR and trends in a range of male reproductive problems, including testicular cancer, disorders of sex development, cryptorchidism, hypospadias, low testosterone levels, poor semen quality, childlessness, changed sex ratio, and increasing demand for assisted reproductive techniques. We present evidence that several adult male reproductive problems arise in utero and are signs of testicular dysgenesis syndrome (TDS). Although TDS might result from genetic mutations, recent evidence suggests that it most often is related to environmental exposures of the fetal testis. However, environmental factors can also affect the adult endocrine system. Based on our review of genetic and environmental factors, we conclude that environmental exposures arising from modern lifestyle, rather than genetics, are the most important factors in the observed trends. These environmental factors might act either directly or via epigenetic mechanisms. In the latter case, the effects of exposures might have an impact for several generations post-exposure. In conclusion, there is an urgent need to prioritize research in reproductive physiology and pathophysiology, particularly in highly industrialized countries facing decreasing populations. We highlight a number of topics that need attention by researchers in human physiology, pathophysiology, environmental health sciences, and demography.

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.

Pathway-based analysis of GWAs data identifies association of sex determination genes with susceptibility to testicular germ cell tumors

Genome-wide association (GWA) studies of testicular germ cell tumor (TGCT) have identified 18 susceptibility loci, some containing genes encoding proteins important in male germ cell development. Deletions of one of these genes, DMRT1, lead to male-to-female sex reversal and are associated with development of gonadoblastoma. To further explore genetic association with TGCT, we undertook a pathway-based analysis of SNP marker associations in the Penn GWAs (349 TGCT cases and 919 controls). We analyzed a custom-built sex determination gene set consisting of 32 genes using three different methods of pathway-based analysis. The sex determination gene set ranked highly compared with canonical gene sets, and it was associated with TGCT (FDRG = 2.28 × 10(-5), FDRM = 0.014 and FDRI = 0.008 for Gene Set Analysis-SNP (GSA-SNP), Meta-Analysis Gene Set Enrichment of Variant Associations (MAGENTA) and Improved Gene Set Enrichment Analysis for Genome-wide Association Study (i-GSEA4GWAS) analysis, respectively). The association remained after removal of DMRT1 from the gene set (FDRG = 0.0002, FDRM = 0.055 and FDRI = 0.009). Using data from the NCI GWA scan (582 TGCT cases and 1056 controls) and UK scan (986 TGCT cases and 4946 controls), we replicated these findings (NCI: FDRG = 0.006, FDRM = 0.014, FDRI = 0.033, and UK: FDRG = 1.04 × 10(-6), FDRM = 0.016, FDRI = 0.025). After removal of DMRT1 from the gene set, the sex determination gene set remains associated with TGCT in the NCI (FDRG = 0.039, FDRM = 0.050 and FDRI = 0.055) and UK scans (FDRG = 3.00 × 10(-5), FDRM = 0.056 and FDRI = 0.044). With the exception of DMRT1, genes in the sex determination gene set have not previously been identified as TGCT susceptibility loci in these GWA scans, demonstrating the complementary nature of a pathway-based approach for genome-wide analysis of TGCT.

Tumor loci and their interactions on mouse chromosome 19 that contribute to testicular germ cell tumors

BACKGROUND

Complex genetic factors underlie testicular germ cell tumor (TGCT) development. One experimental approach to dissect the genetics of TGCT predisposition is to use chromosome substitution strains, such as the 129.MOLF-Chr 19 (M19). M19 carries chromosome (Chr) 19 from the MOLF whereas all other chromosomes are from the 129 strain. 71% of M19 males develop TGCTs in contrast to 5% in 129 strain. To identify and map tumor loci from M19 we generated congenic strains harboring MOLF chromosome 19 segments on 129 strain background and monitored their TGCT incidence.

RESULTS

We found 3 congenic strains that each harbored tumor promoting loci that had high (14%-32%) whereas 2 other congenics had low (4%) TGCT incidences. To determine how multiple loci influence TGCT development, we created double and triple congenic strains. We found additive interactions were predominant when 2 loci were combined in double congenic strains. Surprisingly, we found an example where 2 loci, both which do not contribute significantly to TGCT, when combined in a double congenic strain resulted in greater than expected TGCT incidence (positive interaction). In an opposite example, when 2 loci with high TGCT incidences were combined, males of the double congenic showed lower than expected TGCT incidence (negative interaction). For the triple congenic strain, depending on the analysis, the overall TGCT incidence could be additive or could also be due to a positive interaction of one region with others. Additionally, we identified loci that promote bilateral tumors or testicular abnormalities.

CONCLUSIONS

The congenic strains each with their characteristic TGCT incidences, laterality of tumors and incidence of testicular abnormalities, are useful for identification of TGCT susceptibility modifier genes that map to Chr 19 and also for studies on the genetic and environmental causes of TGCT development. TGCTs are a consequence of aberrant germ cell and testis development. By defining predisposing loci and some of the locus interactions from M19, this study further advances our understanding of the complex genetics of TGCTs, which is the most common cancer in young human males.

SNPs in KIT and KITLG genes may be associated with oligospermia in Chinese population

KIT/KITLG signaling system is crucial for spermatogenesis, which suggests that KIT and KITLG genes may be involved in spermatogenesis impairment and male infertility. To explore the possible association of KIT and KITLG genes with male infertility having spermatogenesis impairment, polymorphism distributions of SNP rs3819392 in KIT gene as well as rs995030 and rs4474514 in KITLG gene were investigated in 372 patients with idiopathic azoospermia or oligospermia and 205 fertile controls. As a result, the significant differences in polymorphism distributions of SNP rs3819392 in KIT gene and rs4474514 in KITLG gene were observed between the patients with oligospermia and controls. The frequencies of allele G (94.2% versus 90.0% p = 0.022) and genotype GG (89.2% versus 82.0% p = 0.042) in patients with oligospermia were significantly higher than those in controls at rs3819392 locus in KIT gene. In addition, the genotype CC of rs4474514 in KITLG (8.2% versus 3.4%, p = 0.034) also significantly increased in oligospermic patients in comparison to controls. These findings indicated that SNP rs3819392 in KIT gene and rs4474514 in KITLG gene may be associated with oligospermia, suggesting that polymorphism of KIT and KITLG genes may play a role in oligospermia.

Contrasting effects of Deadend1 (Dnd1) gain and loss of function mutations on allelic inheritance, testicular cancer, and intestinal polyposis

Background

Certain mutations in the Deadend1 (Dnd1) gene are the most potent modifiers of testicular germ cell tumor (TGCT) susceptibility in mice and rats. In the 129 family of mice, the Dnd1^Ter mutation significantly increases occurrence of TGCT-affected males. To test the hypothesis that he Dnd1^Ter allele is a loss-of-function mutation; we characterized the consequences of a genetically-engineered loss-of-function mutation in mice, and compared these results with those for Dnd1^Ter.

Results

We found that intercrossing Dnd1^+/KO heterozygotes to generate a complete loss-of-function led to absence of Dnd1^KO/KO homozygotes and significantly reduced numbers of Dnd1^+/KO heterozygotes. Further crosses showed that Dnd1^Ter partially rescues loss of Dnd1^KO mice. We also found that loss of a single copy of Dnd1 in Dnd1^KO/+ heterozygotes did not affect baseline occurrence of TGCT-affected males and that Dnd1^Ter increased TGCT risk regardless whether the alternative allele was loss-of-function (Dnd1^KO) or wild-type (Dnd1⁺). Finally, we found that the action of Dnd1^Ter was not limited to testicular cancer, but also significantly increased polyp number and burden in the Apc^+/Min model of intestinal polyposis.

Conclusion

These results show that Dnd1 is essential for normal allelic inheritance and that Dnd1^Ter has a novel combination of functions that significantly increase risk for both testicular and intestinal cancer.

Molecular characteristics of malignant ovarian germ cell tumors and comparison with testicular counterparts: implications for pathogenesis

This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors.

Children's Oncology Group's 2013 blueprint for research: epidemiology

Investigators worldwide have for over 40 years conducted case-control studies aimed at determining the causes of childhood cancer. The central challenge to conducting such research is the rarity of childhood cancer, thus many studies aggregate cases through clinical trials organizations such as COG. Rarity also precludes the use of prospective study designs, which are less prone to recall and selection biases. Despite these challenges a substantial literature on childhood cancer etiology has emerged but few strong environmental risk factors have been identified. Genetic studies are thus now coming to the fore with some success. The ultimate aim of epidemiologic studies is to reduce the population burden of childhood cancer by suggesting preventive measures or possibly by enabling early detection. Pediatr Blood Cancer 2013; 60: 1059-1062. © 2012 Wiley Periodicals, Inc.

Dysregulation of the mitosis-meiosis switch in testicular carcinoma in situ

Testicular germ cell tumours (TGCT) of young adults arise from the intratubular precursor, carcinoma in situ (CIS). CIS cells are thought to be developmentally arrested and transformed fetal germ cells that survive through childhood and gain invasive capacity after puberty. Given that germ cell neoplasms arise frequently in undervirilized and dysgenetic gonads and the striking physiological difference between meiotic entry in ovaries (fetal life) versus testes (at puberty), this study aimed to investigate whether errors in regulation of meiosis may be implicated in the pathogenesis of CIS or its invasive progression to TGCT. The main focus was on a key sex differentiation and meiosis regulator, DMRT1, which has also been linked to TGCT risk in recent genetic association studies. Expression patterns of DMRT1 and other meiosis regulators (SCP3, DMC1, STRA8, CYP26B1, NANOS2, NANOS3) were investigated in pre- and post-pubertal CIS samples and TGCT by quantitative RT-PCR and immunohistochemistry. The results demonstrated that meiosis markers and meiosis inhibitors were simultaneously expressed in CIS cells, in both pre- and post-pubertal testis samples. DMRT1 was present in a restricted subset of CIS cells, which was relatively greater in pre-pubertal (27%) compared to adult (2.6%) samples. In contrast to the majority of CIS cells, DMRT1-positive CIS cells in adult testes were not proliferating. DMRT1 and most of the other meiosis regulators were absent or expressed at low levels in invasive TGCT, except in spermatocytic seminoma (not derived from CIS). In conclusion, this study indicates that meiosis signalling is dysregulated in CIS cells and that a key regulator of the mitosis-meiosis switch, DMRT1, is expressed in 'early-stage' CIS cells but is down-regulated with further invasive transformation. Whether this mixed meiosis signalling in CIS cells is caused by insufficient virilization of the fetal somatic niche or a partial post-pubertal maturation remains uncertain and requires further study.