Meta-analysis identifies four new loci associated with testicular germ cell tumor

Single nucleotide polymorphisms of CFAP43 and TEX14 associated with idiopathic male infertility in a Vietnamese population

Male infertility is a multifactorial disease due to spermatogenesis impairment, with etiology remaining unknown for roughly one-third of infertile cases. Several studies have demonstrated that genetic variants are male infertility risk factors. CFAP43 and TEX14 are involved in the spermatogenesis process. The present study aimed to assess the association between single-nucleotide polymorphisms (SNPs) in CFAP43 (rs17116635 and rs10883979) and TEX14 (rs79813370 and rs34818467) and idiopathic male infertility in a Vietnamese population. A cohort of 206 infertile men and 195 controls were recruited for the study. CFAP43 and TEX14 SNPs were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Genotypes of randomly selected samples, accounting for 10% of the total, were confirmed using Sanger sequencing. The obtained data were analyzed using statistical methods. The results showed that 4 SNPs (rs17116635, rs10883979, rs79813370, and rs34818467) were in accordance with Hardy-Weinberg Equilibrium (HWE; P > .05). CFAP43 rs10883979 and TEX14 rs79813370 were associated with male infertility. For CFAP43 rs10883979, in the recessive model, the combination AA + AG was associated with male infertility when compared to the GG genotype (OR = 0.26; 95% CI: 0.06-0.85; P = .02). For TEX14 rs79813370, a protective effect against infertility risk was identified in the presence of the T allele of rs79813370 when compared to the G allele (OR = 0.48; 95% CI: 0.32-0.72; P < .001). Our results suggest that CFAP43 rs10883979 and TEX14 rs79813370 are likely associated with male infertility in the Vietnamese population, in which the G allele of rs79813370 may be a risk factor for male infertility.

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

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

HEATR3 involved in the cell proliferation, metastasis and cell cycle development of bladder cancer acts as a tumor suppressor

The study was designed to detect the expression and clinical significance of the HEATR3 gene in bladder cancer (BCa) and to preliminarily explore whether this gene can affect the occurrence and development of BCa through the AKT/ERK signaling pathway. The expression and prognostic value of HEATR3 were explored based on The Cancer Genome Atlas (TCGA) and Genotypic Tissue Expression (GTEx) databases. Microarray immunohistochemical analysis was performed in 30 BCa cases to investigate the level of HEATR3 protein and to explore the relationship between HEATR3 and the clinicopathological features of BCa. Western Blot and qRT-PCR were used to detect HEATR3 protein and mRNA in BCa cell lines (5637, TCCSUP, SW780) and fallopian tube epithelial cell (SV-HUC-1). CCK8 method was employed to study the proliferation of BCa cells after heat treatment. Transwell assay was conducted to analyze the effect of HEATR3 on cell migration and invasion. And cell cycle and apoptosis were detected by flow cytometry. Furthermore, Western Blot assay was used to probe the effects of down-regulation of HEATR3 expression on the expression and phosphorylation levels of AKT and ERK proteins in BCa cells. Bioinformatics analysis showed that HEATR3 was significantly up-regulated in BCa, and high HEATR3 expression was associated with poor prognosis of BCa patients. In vitro experiments demonstrated that HEATR3 expression was up-regulated in BCa tissues compared with that in adjacent tissues. HEATR3 protein was also up-regulated in malignant cell lines. HEATR3 knockdown in BCa cells could inhibit cell proliferation, invasion and migration, block cell cycle and promote cell apoptosis. At the same time, HEATR3 knockdowns reduced the expression levels of p-AKT and p-ERK proteins. HEATR3 knockdown inhibits the development of BCa cells through the AKT/ERK signaling pathway. and it may become one of the most promising molecular targets for BCa treatment.

Cross-cancer pleiotropic analysis identifies three novel genetic risk loci for colorectal cancer

BACKGROUND

To understand the shared genetic basis between colorectal cancer (CRC) and other cancers and identify potential pleiotropic loci for compensating the missing genetic heritability of CRC.

METHODS

We conducted a systematic genome-wide pleiotropy scan to appraise associations between cancer-related genetic variants and CRC risk among European populations. Single nucleotide polymorphism (SNP)-set analysis was performed using data from the UK Biobank and the Study of Colorectal Cancer in Scotland (10 039 CRC cases and 30 277 controls) to evaluate the overlapped genetic regions for susceptibility of CRC and other cancers. The variant-level pleiotropic associations between CRC and other cancers were examined by CRC genome-wide association study meta-analysis and the pleiotropic analysis under composite null hypothesis (PLACO) pleiotropy test. Gene-based, co-expression and pathway enrichment analyses were performed to explore potential shared biological pathways. The interaction between novel genetic variants and common environmental factors was further examined for their effects on CRC.

RESULTS

Genome-wide pleiotropic analysis identified three novel SNPs (rs2230469, rs9277378 and rs143190905) and three mapped genes (PIP4K2A, HLA-DPB1 and RTEL1) to be associated with CRC. These genetic variants were significant expressions quantitative trait loci in colon tissue, influencing the expression of their mapped genes. Significant interactions of PIP4K2A and HLA-DPB1 with environmental factors, including smoking and alcohol drinking, were observed. All mapped genes and their co-expressed genes were significantly enriched in pathways involved in carcinogenesis.

CONCLUSION

Our findings provide an important insight into the shared genetic basis between CRC and other cancers. We revealed several novel CRC susceptibility loci to help understand the genetic architecture of CRC.

A deletion variant Arg616 of androgen receptor in a Chinese family with complete androgen insensitivity syndrome

Background: Complete androgen insensitivity syndrome (CAIS, OMIM; 300068) is a disorder of sex development with X-linked recessive inheritance. Cases of CAIS usually present as female phenotype, with primary amenorrhea and/or inguinal hernia. Family aggregation is a rare scenario. Methods: This study is a retrospective analysis of CAIS cases in a three-generation pedigree. The patients' genomes were determined by sequencing the androgen receptor (AR) gene. The clinical data of the patients, including manifestations, hormone levels, and AR variants, were analyzed. Results: Sixteen people in this family were involved. A deletion variant (c.1847_1849del; p. Arg616del) was identified in exon 3 of AR, which encodes the DNA binding domain. Until now, four patients and four carriers have been identified in three generations of this family. All the patients live as female, and one has developed gonadal malignancy. Conclusion: The present study identified a deletion variant in three generations of a family with CAIS, including four carriers and four patients. This study verified the genetic pattern and the corresponding clinical characteristics of CAIS. Furthermore, a case with gonadal malignancy was discovered. The information on diagnosis and treatment in this pedigree is useful for prenatal diagnosis and genetic counseling of similar families.

Endocannabinoid system and epigenetics in spermatogenesis and testicular cancer

In mammals, male germ cell development starts during fetal life and is carried out in postnatal life with the formation of sperms. Spermatogenesis is the complex and highly orderly process during which a group of germ stem cells is set at birth, starts to differentiate at puberty. It proceeds through several stages: proliferation, differentiation, and morphogenesis and it is strictly regulated by a complex network of hormonal, autocrine and paracrine factors and it is associated with a unique epigenetic program. Altered epigenetic mechanisms or inability to respond to these factors can impair the correct process of germ development leading to reproductive disorders and/or testicular germ cell cancer. Among factors regulating spermatogenesis an emerging role is played by the endocannabinoid system (ECS). ECS is a complex system comprising endogenous cannabinoids (eCBs), their synthetic and degrading enzymes, and cannabinoid receptors. Mammalian male germ cells have a complete and active ECS which is modulated during spermatogenesis and that crucially regulates processes such as germ cell differentiation and sperm functions. Recently, cannabinoid receptor signaling has been reported to induce epigenetic modifications such as DNA methylation, histone modifications and miRNA expression. Epigenetic modifications may also affect the expression and function of ECS elements, highlighting the establishment of a complex mutual interaction. Here, we describe the developmental origin and differentiation of male germ cells and testicular germ cell tumors (TGCTs) focusing on the interplay between ECS and epigenetic mechanisms involved in these processes.

Increase and Plateauing of Testicular Cancer Incidence in Austria-A Time Trend Analysis of the Past Four Decades

Background

Testicular germ cell tumors (TGCTs) are the most common malignant tumors in young men. Despite considerable geographic, ethnic, and temporal variations in the incidence of TGCTs, without convincing explanation, incidence rates of TGCTs have been increasing in many countries since, at least, the mid-20th century.

Objective

To investigate the incidence rates of TGCTs in Austria by analyzing data from the Austrian Cancer Registry.

Design setting and participants

Available data between 1983 and 2018 were provided by the Austrian National Cancer Registry and analyzed retrospectively.

Outcome measurements and statistical analysis

Germ cell tumors derived from germ cell neoplasia in situ were classified into seminomas and nonseminomas. Age-specific incidence rates and age-standardized rates were calculated. Annual percent changes (APCs) and average annual percent changes in incidence rates were determined to describe trends from 1983 to 2018. All statistical analyses were performed using SAS version 9.4 and joinpoint.

Results and limitations

The study population consists of 11 705 patients diagnosed with TGCTs. The median age at diagnosis was 37.7 yr. The standardized incidence rate of TGCTs increased significantly (p < 0.0001) from 4.1 (3.4, 4.8) per 100 000 in 1983 to 8.7 (7.9, 9.6) per 100 000 in 2018 by an average APC of 1.74 (1.20, 2.29). The joinpoint regression revealed a change point in time trend in 1995 with an APC of 4.24 (2.77, 5.72) before 1995 and an APC of 0.47 (0.06, 0.89) thereafter. Incidence rates were about twice as high for seminomas as for nonseminomas. A trend analysis by age group showed that the highest TGCT incidence rate was observed among men aged 30-40 yr, with a steep increase before 1995.

Conclusions

The incidence rate of TGCTs increased in Austria over the past decades and appears to have reached a plateau at a high level. A time trend analysis by age group for the overall incidence was highest in men aged 30-40 yr, with a steep increase before 1995. These data should lead to awareness campaigns and research to further investigate the causes of this development.

Patient summary

We reviewed the data between 1983 and 2018 provided by the Austrian National Cancer Registry to analyze the incidence and incidence trend in testicular cancer. Testicular cancer shows an increasing incidence in Austria. The overall incidence was highest in men aged 30-40 yr, with a steep increase before 1995. The incidence appears to have reached a plateau at a high level in recent years.

Bioinformatics Prediction and Machine Learning on Gene Expression Data Identifies Novel Gene Candidates in Gastric Cancer

Gastric cancer (GC) is one of the five most common cancers in the world and unfortunately has a high mortality rate. To date, the pathogenesis and disease genes of GC are unclear, so the need for new diagnostic and prognostic strategies for GC is undeniable. Despite particular findings in this regard, a holistic approach encompassing molecular data from different biological levels for GC has been lacking. To translate Big Data into system-level biomarkers, in this study, we integrated three different GC gene expression data with three different biological networks for the first time and captured biologically significant (i.e., reporter) transcripts, hub proteins, transcription factors, and receptor molecules of GC. We analyzed the revealed biomolecules with independent RNA-seq data for their diagnostic and prognostic capabilities. While this holistic approach uncovered biomolecules already associated with GC, it also revealed novel system biomarker candidates for GC. Classification performances of novel candidate biomarkers with machine learning approaches were investigated. With this study, AES, CEBPZ, GRK6, HPGDS, SKIL, and SP3 were identified for the first time as diagnostic and/or prognostic biomarker candidates for GC. Consequently, we have provided valuable data for further experimental and clinical efforts that may be useful for the diagnosis and/or prognosis of GC.

HPGDS is a novel prognostic marker associated with lipid metabolism and aggressiveness in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is the most common respiratory globallywith a poor prognosis. Lipid metabolism is extremely important for the occurrence and development of cancer. However, the role of genes involved in lipid metabolism in LUAD development is unclear. We aimed to identify the abnormal lipid metabolism pathway of LUAD, construct a novel prognostic model of LUAD, and discover novel biomarkers involved in lipid metabolism in LUAD.

METHODS

Based on differentially expressed genes involved in lipid metabolism in LUAD samples from The Cancer Genome Atlas (TCGA), abnormal lipid metabolism pathways in LUAD were analyzed. The lasso penalized regression analysis was performed on the TCGA cohort (training set) to construct a risk score formula. The predictive ability of the risk score was validated in the Gene Expression Omnibus (GEO) dataset (validation set) using Kaplan-Meier analysis and ROC curves. Finally, based on CRISPR gene editing technology, hematopoietic prostaglandin D synthase (HPGDS) was knocked out in A549 cell lines, the changes in lipid metabolism-related markers were detected by western blotting, and the changes in cell migration were detected by transwell assay.

RESULTS

Based on the differential genes between lung cancer tissue and normal tissue, we found that the arachidonic acid metabolism pathway is an abnormal lipid metabolism pathway in both lung adenocarcinoma and lung squamous cell carcinoma. Based on the sample information of TCGA and abnormally expressed lipid metabolism-related genes, a 9-gene prognostic risk score was successfully constructed and validated in the GEO dataset. Finally, we found that knockdown of HPGDS in A549 cell lines promoted lipid synthesis and is more invasive than in control cells. Rescue assays showed that ACSL1 knockdown reversed the pro-migration effects of HPGDS knockdown. The knockdown of HPGDS promoted migration response by upregulating the expression of the lipid metabolism key enzymes ACSL1 and ACC.

CONCLUSION

The genes involved in lipid metabolism are associated with the occurrence and development of LUAD. HPGDS can be a therapeutic target of a potential lipid metabolism pathway in LUAD, and the therapeutic target of lipid metabolism genes in LUAD should be studied further.

Evolutionary Origins of Metabolic Reprogramming in Cancer

Metabolic changes that facilitate tumor growth are one of the hallmarks of cancer. These changes are not specific to tumors but also take place during the physiological growth of tissues. Indeed, the cellular and tissue mechanisms present in the tumor have their physiological counterpart in the repair of tissue lesions and wound healing. These molecular mechanisms have been acquired during metazoan evolution, first to eliminate the infection of the tissue injury, then to enter an effective regenerative phase. Cancer itself could be considered a phenomenon of antagonistic pleiotropy of the genes involved in effective tissue repair. Cancer and tissue repair are complex traits that share many intermediate phenotypes at the molecular, cellular, and tissue levels, and all of these are integrated within a Systems Biology structure. Complex traits are influenced by a multitude of common genes, each with a weak effect. This polygenic component of complex traits is mainly unknown and so makes up part of the missing heritability. Here, we try to integrate these different perspectives from the point of view of the metabolic changes observed in cancer.

Implementation of individualised polygenic risk score analysis: a test case of a family of four

BACKGROUND

Polygenic risk scores (PRS) have been widely applied in research studies, showing how population groups can be stratified into risk categories for many common conditions. As healthcare systems consider applying PRS to keep their populations healthy, little work has been carried out demonstrating their implementation at an individual level.

CASE PRESENTATION

We performed a systematic curation of PRS sources from established data repositories, selecting 15 phenotypes, comprising an excess of 37 million SNPs related to cancer, cardiovascular, metabolic and autoimmune diseases. We tested selected phenotypes using whole genome sequencing data for a family of four related individuals. Individual risk scores were given percentile values based upon reference distributions among 1000 Genomes Iberians, Europeans, or all samples. Over 96 billion allele effects were calculated in order to obtain the PRS for each of the individuals analysed here.

CONCLUSIONS

Our results highlight the need for further standardisation in the way PRS are developed and shared, the importance of individual risk assessment rather than the assumption of inherited averages, and the challenges currently posed when translating PRS into risk metrics.

Genetics of testicular cancer: a review

PURPOSE OF REVIEW

Testicular germ cell tumours (TGCTs) are the most common solid malignant cancer diagnosed in young males and the incidence is increasing. Understanding the genetic basis of this disease will help us to navigate the challenges of early detection, diagnosis, treatment, surveillance, and long-term outcomes for patients.

RECENT FINDINGS

TGCTs are highly heritable. Current understanding of germline risk includes the identification of one moderate-penetrance predisposition gene, checkpoint kinase 2 (CHEK2), and 78 low-to-moderate-risk single nucleotide polymorphisms identified in genome-wide-associated studies, which account for 44% of familial risk. Biomarker research in TGCTs has been challenging for multiple reasons: oncogenesis is complex, actionable mutations are uncommon, clonal evolution unpredictable and tumours can be histologically and molecularly heterogeneous. Three somatic mutations have thus far been identified by DNA exome sequencing, exclusively in seminomas: KIT, KRAS and NRAS. Several genetic markers appear to be associated with risk of TGCT and treatment resistance. TP53 mutations appear to be associated with platinum resistance. MicroRNA expression may be a useful biomarker of residual disease and relapse in future.

SUMMARY

The biology of testicular germ cells tumours is complex, and further research is needed to fully explain the high heritability of these cancers, as well as the molecular signatures which may drive their biological behaviour.

Genomic Profile in a Non-Seminoma Testicular Germ-Cell Tumor Cohort Reveals a Potential Biomarker of Sensitivity to Platinum-Based Therapy

Despite having a favorable response to platinum-based chemotherapies, ~15% of Testicular Germ-Cell Tumor (TGCT) patients are platinum-resistant. Mortality rates among Latin American countries have remained constant over time, which makes the study of this population of particular interest. To gain insight into this phenomenon, we conducted whole-exome sequencing, microarray-based comparative genomic hybridization, and copy number analysis of 32 tumors from a Mexican cohort, of which 18 were platinum-sensitive and 14 were platinum-resistant. We incorporated analyses of mutational burden, driver mutations, and SNV and CNV signatures. DNA breakpoints in genes were also investigated and might represent an interesting research opportunity. We observed that sensitivity to chemotherapy does not seem to be explained by any of the mutations detected. Instead, we uncovered CNVs, particularly amplifications on segment 2q11.1 as a novel variant with chemosensitivity biomarker potential. Our data shed light into understanding platinum resistance in a Latin-origin population.

Identification of 22 susceptibility loci associated with testicular germ cell tumors

Testicular germ cell tumors (TGCT) are the most common tumor in young white men and have a high heritability. In this study, the international Testicular Cancer Consortium assemble 10,156 and 179,683 men with and without TGCT, respectively, for a genome-wide association study. This meta-analysis identifies 22 TGCT susceptibility loci, bringing the total to 78, which account for 44% of disease heritability. Men with a polygenic risk score (PRS) in the 95th percentile have a 6.8-fold increased risk of TGCT compared to men with median scores. Among men with independent TGCT risk factors such as cryptorchidism, the PRS may guide screening decisions with the goal of reducing treatment-related complications causing long-term morbidity in survivors. These findings emphasize the interconnected nature of two known pathways that promote TGCT susceptibility: male germ cell development within its somatic niche and regulation of chromosomal division and structure, and implicate an additional biological pathway, mRNA translation.

On the origin of germ cell neoplasia in situ: Dedifferentiation of human adult Sertoli cells in cross talk with seminoma cells in vitro

Germ cell neoplasia in situ (GCNIS) is the noninvasive precursor of testicular germ cell tumors type II, the most common cancer in young men, which originates from embryonic germ cells blocked in their maturation. GCNIS is associated with impaired Sertoli cells (SCs) that express fetal keratin 18 (KRT18) and the pluripotency factor SRY-Box transcription factor 2 (SOX2). According to the current theory concerning the origin of GCNIS, these SCs are prepubertal cells arrested in their maturation due to (epi)genetic anomalies and/or environmental antiandrogens. Thus, they are unable to support the development of germ cells, which leads to their maturational block and further progresses into GCNIS. Alternatively, these SCs are hypothesized to be adult cells dedifferentiating secondarily under the influence of GCNIS. To examine whether tumor cells can dedifferentiate SCs, we established a coculture model of adult human SCs (FS1) and a seminoma cell line similar to GCNIS (TCam-2). After 2 wk of coculture, FS1 cells showed progressive expression of KRT18 and SOX2, mimicking the in vivo changes. TCam-2 cells showed SOX2 expression and upregulation of further pluripotency- and reprogramming-associated genes, suggesting a seminoma to embryonal carcinoma transition. Thus, our FS1/TCam-2 coculture model is a valuable tool for investigating interactions between SCs and seminoma cells. Our immunohistochemical and ultrastructural studies of human testicular biopsies with varying degrees of GCNIS compared to biopsies from fetuses, patients with androgen insensitivity syndrome, and patients showing normal spermatogenesis further suggest that GCNIS-associated SCs represent adult cells undergoing progressive dedifferentiation.

Malignant Germ Cell Tumors and Their Precursor Gonadal Lesions in Patients with XY-DSD: A Case Series and Review of the Literature

The risk of gonadal germ cell tumors is increased over the lifetime of patients with XY-disorders of sex development (XY-DSD). The aim of this study was to evaluate clinical features and histopathological outcome after gonadectomy in patients with XY-DSD to assess the risk of malignant transformation to gonadal germ cell tumors. Thirty-five women treated for XY-DSD at our hospital between 2003 and 2020 were enrolled in this study. Twenty-seven (77%) underwent prophylactic gonadectomy, 10 (29%) at our department and 17 (48%) at external hospitals. Eight (23%) patients didn’t receive gonadectomy. Of the patients who underwent a surgical procedure at our hospital, two patients were diagnosed with a unilateral seminoma, one patient with a bilateral and one patient with a unilateral Sertoli cell adenoma. According to these findings, preventive gonadectomy in patients with XY-DSD should be taken into consideration. Guidelines concerning the necessity of gonadectomy to avoid malignant transformation are still lacking. The risk of malignant germ cell tumors from rudimentary gonads has not been investigated sufficiently to date, as it is mostly based on case series due to the rarity of the condition. In our study we retrospectively analyzed patients who partly underwent bilateral gonadectomy, aiming to fill this gap. Concerning the ideal point of time for gonadectomy, further studies with a higher number of patients are needed.

Between a Rock and a Hard Place: An Epigenetic-Centric View of Testicular Germ Cell Tumors

Simple Summary

This minireview focuses on the role of epigenetics in testicular cancer. A working model is developed that postulates that epigenetic features that drive testicular cancer malignancy also enable these tumors to be cured at a high rate with chemotherapy. Chemoresistance may occur by epigenetic uncoupling of malignancy and chemosensitivity, a scenario that may be amenable to epigenetic-based therapies.

Abstract

Compared to many common solid tumors, the main genetic drivers of most testicular germ cell tumors (TGCTs) are unknown. Decades of focus on genomic alterations in TGCTs including awareness of a near universal increase in copies of chromosome 12p have failed to uncover exceptional driver genes, especially in genes that can be targeted therapeutically. Thus far, TGCT patients have missed out on the benefits of targeted therapies available to treat most other malignancies. In the past decade there has been a greater appreciation that epigenetics may play an especially prominent role in TGCT etiology, progression, and hypersensitivity to conventional chemotherapy. While genetics undoubtedly plays a role in TGCT biology, this mini-review will focus on the epigenetic “states” or features of testicular cancer, with an emphasis on DNA methylation, histone modifications, and miRNAs associated with TGCT susceptibility, initiation, progression, and response to chemotherapy. In addition, we comment on the current status of epigenetic-based therapy and epigenetic biomarker development for TGCTs. Finally, we suggest a unifying “rock and a hard place” or “differentiate or die” model where the tumorigenicity and curability of TGCTs are both dependent on common but still ill-defined epigenetic states.

Promoter methylation of DNA homologous recombination genes is predictive of the responsiveness to PARP inhibitor treatment in testicular germ cell tumors

Testicular germ cell tumors (TGCTs) are the most common cancers in men aged 15-39 years and are divided into two major groups, seminomas and nonseminomas. Novel treatment options are required for these patients, to limit side effects of chemotherapy. We hypothesized that promoter methylation of relevant homologous recombination (HR) genes might be predictive of response to poly-ADP ribose polymerase inhibitors (PARPis) in TGCTs. We report a study pipeline combining in silico, in vitro, and clinical steps. By using several databases and in silico tools, we identified BRCA1, RAD51C, PALB2, RAD54B, and SYCP3 as the most relevant genes for further investigation and pinpointed specific CpG sites with pronounced negative correlation to gene expression. Nonseminomas displayed significantly higher methylation levels for all target genes, where increased methylation was observed in patients with more differentiated subtypes and higher disease burden. We independently performed second-line targeted validation in tissue series from TGCT patients. A moderate and/or strong anti-correlation between gene expression (assessed by RNA-sequencing) and promoter methylation (assessed by 450k array) was found, for all of the targets. As a proof of concept, we demonstrated the sensitivity of TGCT cell lines to Olaparib, which associated with differential methylation levels of a subset of targets, namely BRCA1 and RAD51C. Our findings support the use of HR genes promoter methylation as a predictor of the therapeutic response to PARPis in patients with TGCT.

Potential biomarkers for testicular germ cell tumour: Risk assessment, diagnostic, prognostic and monitoring of recurrence

Testicular germ cell tumour (TGCT) is considered a relatively rare malignancy usually occurring in young men between 15 and 35 years of age, and both genetic and environmental factors contribute to its development. The majority of patients are diagnosed in an early-stage of TGCTs with an elevated 5-year survival rate after therapy. However, approximately 25% of patients show an incomplete response to chemotherapy or tumours relapse. The current therapies are accompanied by several adverse effects, including infertility. Aside from classical serum biomarker, many studies reported novel biomarkers for TGCTs, but without proper validation. Cancer cells share many similarities with embryonic stem cells (ESCs), and since ESC genes are not transcribed in most adult tissues, they could be considered ideal candidate targets for cancer-specific diagnosis and treatment. Added to this, several microRNAs (miRNA) including miRNA-371-3p can be further investigated as a molecular biomarker for diagnosis and monitoring of TGCTs. In this review, we will illustrate the findings of recent investigations in novel TGCTs biomarkers applicable for risk assessment, screening, diagnosis, prognosis, prediction and monitoring of the relapse.

Lower abdominal and pelvic radiation and testicular germ cell tumor risk

Background

Testicular germ cell tumor (TGCT) incidence has increased in recent decades along with the use and dose of diagnostic radiation. Here we examine the association between reported exposure to diagnostic radiation and TGCT risk.

Methods

We conducted a case-control study of men with and without TGCT recruited from hospital- and population-based settings. Participants reported on exposures to 1) x-ray or CT below the waist and 2) lower GI series or barium enema, which consists of a series of x-rays of the colon. We also derived a combined measure of exposure. We used logistic regression to determine the risk of developing TGCT according to categories of exposures (0, 1–2, or ≥3 exposures) and age at first exposure, adjusting for age, year of birth, race, county, body mass index at diagnosis, family history of TGCT, and personal history of cryptorchidism.

Results

There were 315 men with TGCT and 931 men without TGCT in our study. Compared to no exposures, risk of TGCT was significantly elevated among those reporting at least three exposures to x-ray or CT (OR_{≥3 exposures}, 1.78; 95% CI, 1.15–2.76; p = 0.010), lower GI series or barium enema (OR_{≥3 exposures}, 4.58; 95% CI, 2.39–8.76; p<0.001), and the combined exposure variable (OR_{≥3 exposures}, 1.59; 95% CI, 1.05–2.42; p = 0.029). The risk of TGCT was elevated for those exposed to diagnostic radiation at age 0–10 years, compared to those first exposed at age 18 years or later, although this association did not reach statistical significance (OR, 2.00; 95% CI, 0.91–4.42; p = 0.086).

Conclusions

Exposure to diagnostic radiation below the waist may increase TGCT risk. If these results are validated, efforts to reduce diagnostic radiation doses to the testes should be prioritized.

Alteration of genome folding via contact domain boundary insertion

Animal chromosomes are partitioned into contact domains. Pathogenic domain disruptions can result from chromosomal rearrangements or perturbation of architectural factors. However, such broad-scale alterations are insufficient to define the minimal requirements for domain formation. Moreover, to what extent domains can be engineered is just beginning to be explored. In an attempt to create contact domains, we inserted a 2-kb DNA sequence underlying a tissue-invariant domain boundary-containing a CTCF-binding site (CBS) and a transcription start site (TSS)-into 16 ectopic loci across 11 chromosomes, and characterized its architectural impact. Depending on local constraints, this fragment variably formed new domains, partitioned existing ones, altered compartmentalization and initiated contacts reflecting chromatin loop extrusion. Deletions of the CBS or the TSS individually or in combination within inserts revealed its distinct contributions to genome folding. Altogether, short DNA insertions can suffice to shape the spatial genome in a manner influenced by chromatin context.

Frequent copy number gains of SLC2A3 and ETV1 in testicular embryonal carcinomas

Testicular germ cell tumours (TGCTs) appear as different histological subtypes or mixtures of these. They show similar, multiple DNA copy number changes, where gain of 12p is pathognomonic. However, few high-resolution analyses have been performed and focal DNA copy number changes with corresponding candidate target genes remain poorly described for individual subtypes. We present the first high-resolution DNA copy number aberration (CNA) analysis on the subtype embryonal carcinomas (ECs), including 13 primary ECs and 5 EC cell lines. We identified recurrent gains and losses and allele-specific CNAs. Within these regions, we nominate 30 genes that may be of interest to the EC subtype. By in silico analysis of data from 150 TGCTs from The Cancer Genome Atlas (TCGA), we further investigated CNAs, RNA expression, somatic mutations and fusion transcripts of these genes. Among primary ECs, ploidy ranged between 2.3 and 5.0, and the most common aberrations were DNA copy number gains at chromosome (arm) 7, 8, 12p, and 17, losses at 4, 10, 11, and 18, replicating known TGCT genome characteristics. Gain of whole or parts of 12p was found in all samples, including a highly amplified 100 kbp segment at 12p13.31, containing SLC2A3. Gain at 7p21, encompassing ETV1, was the second most frequent aberration. In conclusion, we present novel CNAs and the genes located within these regions, where the copy number gain of SLC2A3 and ETV1 are of interest, and which copy number levels also correlate with expression in TGCTs.

Increasing Incidence of Testicular Germ Cell Tumors among Racial/Ethnic Minorities in the United States

BACKGROUND

The incidence of testicular germ cell tumors (TGCT) has been rising in the United States and is notably higher among white men. Previously, our group reported that rates were rising among Hispanic men in certain areas. This study sought to determine whether the patterns noted in our prior publication remained evident in more recent years and to determine whether any new patterns have emerged.

METHODS

Data from 51 U.S. cancer registries were examined. Racial/ethnic-specific incidence rates per 100,000 man-years were calculated overall and by census region. Annual percent changes (APC) were estimated, and joinpoint models were fit. Differences in regional incidence were examined using the Wald test.

RESULTS

During the time period 2001 to 2016, 126,575 TGCTs were recorded. TGCT incidence was highest among non-Hispanic whites (NHW; 6.63/100,000), followed by Hispanics (4.20), American Indian/Alaska Natives (AI/AN; 3.27), Asian/Pacific Islanders (A/PI; 1.72), and non-Hispanic blacks (NHB; 1.27). TGCT incidence increased significantly among all men; the greatest increase was experienced by A/PIs (APC: 2.47), followed in order by Hispanics (2.10), AI/ANs (1.71), NHBs (1.28), and NHWs (0.41). Significant differences in rates by region were seen for all men except NHBs, with the highest rates among Hispanics (5.38/100,000), AI/ANs (4.47), and A/PIs (2.37) found in the West, and among NHWs (7.60) and NHBs (1.51) found in the Northeast.

CONCLUSIONS

Although TGCT incidence remained highest among NHWs between 2001 and 2016, the greatest increase was experienced by A/PI men.

IMPACT

Rising rates of TGCTs among men of all racial/ethnic backgrounds in the United States suggest that future attention is warranted.

Association of Inherited Pathogenic Variants in Checkpoint Kinase 2 (CHEK2) With Susceptibility to Testicular Germ Cell Tumors

Importance

Approximately 50% of the risk for the development of testicular germ cell tumors (TGCTs) is estimated to be heritable, but no mendelian TGCT predisposition genes have yet been identified. It is hypothesized that inherited pathogenic DNA repair gene (DRG) alterations may drive susceptibility to TGCTs.

Objective

To systematically evaluate the enrichment of germline pathogenic variants in the mendelian cancer predisposition DRGs in patients with TGCTs vs healthy controls.

Design, Setting, and Participants

A case-control enrichment analysis was performed from January 2016 to May 2018 to screen for 48 DRGs in 205 unselected men with TGCT and 27 173 ancestry-matched cancer-free individuals from the Exome Aggregation Consortium cohort in the discovery stage. Significant findings were selectively replicated in independent cohorts of 448 unselected men with TGCTs and 442 population-matched controls, as well as 231 high-risk men with TGCTs and 3090 ancestry-matched controls. Statistical analysis took place from January to May 2018.

Main Outcomes and Measures

Gene-level enrichment analysis of germline pathogenic variants in individuals with TGCTs relative to cancer-free controls.

Results

Among 205 unselected men with TGCTs (mean [SD] age, 33.04 [9.67] years), 22 pathogenic germline DRG variants, one-third of which were in CHEK2 (OMIM 604373), were identified in 20 men (9.8%; 95% CI, 6.1%-14.7%). Unselected men with TGCTs were approximately 4 times more likely to carry germline loss-of-function CHEK2 variants compared with cancer-free individuals from the Exome Aggregation Consortium cohort (odds ratio [OR], 3.87; 95% CI, 1.65-8.86; nominal P = .006; q = 0.018). Similar enrichment was also seen in an independent cohort of 448 unselected Croatian men with TGCTs (mean [SD] age, 31.98 [8.11] years) vs 442 unselected Croatian men without TGCTs (at least 50 years of age at time of sample collection) (OR, >1.4; P = .03) and 231 high-risk men with TGCTs (mean [SD] age, 31.54 [9.24] years) vs 3090 men (all older than 50 years) from the Penn Medicine Biobank (OR, 6.30; 95% CI, 2.34-17.31; P = .001). The low-penetrance CHEK2 variant (p.Ile157Thr) was found to be a Croatian founder TGCT risk variant (OR, 3.93; 95% CI, 1.53-9.95; P = .002). Individuals with the pathogenic CHEK2 loss-of-function variants developed TGCTs 6 years earlier than individuals with CHEK2 wild-type alleles (5.95 years; 95% CI, 1.48-10.42; P = .009).

Conclusions and Relevance

This multicenter case-control analysis of men with or without TGCTs provides evidence for CHEK2 as a novel moderate-penetrance TGCT susceptibility gene, with potential clinical utility. In addition to highlighting DNA-repair deficiency as a potential mechanism driving TGCT susceptibility, this analysis also provides new avenues to explore management strategies and biological investigations for high-risk individuals.

Genetic predisposition for multiple myeloma

Multiple myeloma (MM) is the second most common blood malignancy. Epidemiological family studies going back to the 1920s have provided evidence for familial aggregation, suggesting a subset of cases have an inherited genetic background. Recently, studies aimed at explaining this phenomenon have begun to provide direct evidence for genetic predisposition to MM. Genome-wide association studies have identified common risk alleles at 24 independent loci. Sequencing studies of familial cases and kindreds have begun to identify promising candidate genes where variants with strong effects on MM risk might reside. Finally, functional studies are starting to give insight into how identified risk alleles promote the development of MM. Here, we review recent findings in MM predisposition field, and highlight open questions and future directions.

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.

Integrated Molecular Characterization of Testicular Germ Cell Tumors

We studied 137 primary testicular germ cell tumors (TGCTs) using high-dimensional assays of genomic, epigenomic, transcriptomic, and proteomic features. These tumors exhibited high aneuploidy and a paucity of somatic mutations. Somatic mutation of only three genes achieved significance-KIT, KRAS, and NRAS-exclusively in samples with seminoma components. Integrated analyses identified distinct molecular patterns that characterized the major recognized histologic subtypes of TGCT: seminoma, embryonal carcinoma, yolk sac tumor, and teratoma. Striking differences in global DNA methylation and microRNA expression between histology subtypes highlight a likely role of epigenomic processes in determining histologic fates in TGCTs. We also identified a subset of pure seminomas defined by KIT mutations, increased immune infiltration, globally demethylated DNA, and decreased KRAS copy number. We report potential biomarkers for risk stratification, such as miRNA specifically expressed in teratoma, and others with molecular diagnostic potential, such as CpH (CpA/CpC/CpT) methylation identifying embryonal carcinomas.

Genes associated with testicular germ cell tumors and testicular dysgenesis in patients with testicular microlithiasis

Testicular microlithiasis (TM) is one of the symptoms of testicular dysgenesis syndrome (TDS). TM is particularly interesting as an informative marker of testicular germ cell tumors (TGCTs). KIT ligand gene (KITLG), BCL2 antagonist/killer 1 (BAK1), and sprouty RTK signaling antagonist 4 (SPRY4) genes are associated with a high risk of TGCTs, whereas bone morphogenetic protein 7 gene (BMP7), transforming growth factor beta receptor 3 gene (TGFBR3), and homeobox D cluster genes (HOXD) are related to TDS. Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, we investigated allele and genotype frequencies for KITLG (rs995030, rs1508595), SPRY4 (rs4624820, rs6897876), BAK1 (rs210138), BMP7 (rs388286), TGFBR3 (rs12082710), and HOXD (rs17198432) in 142 TGCT patients, 137 TM patients, and 153 fertile men (control group). We found significant differences in the KITLG GG_rs995030 genotype in TM (P = 0.01) and TGCT patients (P = 0.0005) compared with the control. We also revealed strong associations between KITLG_rs1508595 and TM (G allele, P = 0.003; GG genotype, P = 0.01) and between KITLG_rs1508595 and TGCTs (G allele, P = 0.0001; GG genotype, P = 0.0007). Moreover, there was a significant difference in BMP7_rs388286 between the TGCT group and the control (T allele, P = 0.00004; TT genotype, P = 0.00006) and between the TM group and the control (T allele, P = 0.04). HOXD also demonstrated a strong association with TGCTs (rs17198432 A allele, P = 0.0001; AA genotype, P = 0.001). Furthermore, significant differences were found between the TGCT group and the control in the BAK1_rs210138 G allele (P = 0.03) and the GG genotype (P = 0.01). KITLG and BMP7 genes, associated with the development of TGCTs, may also be related to TM. In summary, the KITLG GG_rs995030, GG_rs1508595, BMP7 TT_rs388286, HOXD AA_rs17198432, and BAK1 GG_rs210138 genotypes were associated with a high risk of TGCT development.

Rare Human Missense Variants can affect the Function of Disease-Relevant Proteins by Loss and Gain of Peroxisomal Targeting Motifs

Single nucleotide variants (SNVs) resulting in amino acid substitutions (i.e., missense variants) can affect protein localization by changing or creating new targeting signals. Here, we studied the potential of naturally occurring SNVs from the Genome Aggregation Database (gnomAD) to result in the loss of an existing peroxisomal targeting signal 1 (PTS1) or gain of a novel PTS1 leading to mistargeting of cytosolic proteins to peroxisomes. Filtering down from 32,985 SNVs resulting in missense mutations within the C-terminal tripeptide of 23,064 human proteins, based on gene annotation data and computational prediction, we selected six SNVs for experimental testing of loss of function (LoF) of the PTS1 motif and five SNVs in cytosolic proteins for gain in PTS1-mediated peroxisome import (GoF). Experimental verification by immunofluorescence microscopy for subcellular localization and FRET affinity measurements for interaction with the receptor PEX5 demonstrated that five of the six predicted LoF SNVs resulted in loss of the PTS1 motif while three of five predicted GoF SNVs resulted in de novo PTS1 generation. Overall, we showed that a complementary approach incorporating bioinformatics methods and experimental testing was successful in identifying SNVs capable of altering peroxisome protein import, which may have implications in human disease.

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.

Update on epidemiologic considerations and treatment trends in testicular cancer

PURPOSE OF REVIEW

We aim to give an overview of the epidemiology and treatment trends of testicular germ cell tumors (TGCTs), with an emphasis on recent trends.

RECENT FINDINGS

The incidence of TGCT appears to be increasing, particularly in developed countries, although the reasons are not well understood. There is evidence of racial differences in predisposition to TGCT, with white men having highest risk and men of African or Asian descent having lower risk. In the United States, the incidence of TGCT among Hispanics appears to be rising most quickly. A recent genomic analysis indicates there is no highly penetrant major TGCT susceptibility gene. Incorporation of multidisciplinary care has led to excellent long-term cure rates; however, access to care and insurance remains barriers in young men. Recent treatment trends have centered on maximizing oncologic outcomes while minimizing long-term morbidity.

SUMMARY

Emerging population-level data provide critical insight into the evolving demographics of TGCT, which may allow for elucidation of biologic and environmental determinants of TGCT. Further, identification of socioeconomic barriers to excellent clinical outcomes will allow for targeted interventions to patients with unique demographic and socioeconomic considerations. Treatment trend analyses suggest that the field is moving toward minimizing treatment-related morbidity.

Testicular germ cell tumor: a comprehensive review

Testicular tumors are the most common tumors in adolescent and young men and germ cell tumors (TGCTs) account for most of all testicular cancers. Increasing incidence of TGCTs among males provides strong motivation to understand its biological and genetic basis. Gains of chromosome arm 12p and aneuploidy are nearly universal in TGCTs, but TGCTs have low point mutation rate. It is thought that TGCTs develop from premalignant intratubular germ cell neoplasia that is believed to arise from the failure of normal maturation of gonocytes during fetal or postnatal development. Progression toward invasive TGCTs (seminoma and nonseminoma) then occurs after puberty. Both inherited genetic factors and environmental risk factors emerge as important contributors to TGCT susceptibility. Genome-wide association studies have so far identified more than 30 risk loci for TGCTs, suggesting that a polygenic model fits better with the genetic landscape of the disease. Despite high cure rates because of its particular sensitivity to platinum-based chemotherapy, exploration of mechanisms underlying the occurrence, progression, metastasis, recurrence, chemotherapeutic resistance, early diagnosis and optional clinical therapeutics without long-term side effects are urgently needed to reduce the cancer burden in this underserved age group. Herein, we present an up-to-date review on clinical challenges, origin and progression, risk factors, TGCT mouse models, serum diagnostic markers, resistance mechanisms, miRNA regulation, and database resources of TGCTs. We appeal that more attention should be paid to the basic research and clinical diagnosis and treatment of TGCTs.

Different Clinical Presentations and Management in Complete Androgen Insensitivity Syndrome (CAIS)

Complete androgen insensitivity syndrome (CAIS) is an X-linked recessive genetic disorder resulting from maternally inherited or de novo mutations involving the androgen receptor gene, situated in the Xq11-q12 region. The diagnosis is based on the presence of female external genitalia in a 46, XY human individual, with normally developed but undescended testes and complete unresponsiveness of target tissues to androgens. Subsequently, pelvic ultrasound or magnetic resonance imaging (MRI) could be helpful in confirming the absence of Mullerian structures, revealing the presence of a blind-ending vagina and identifying testes. CAIS management still represents a unique challenge throughout childhood and adolescence, particularly regarding timing of gonadectomy, type of hormonal therapy, and psychological concerns. Indeed this condition is associated with an increased risk of testicular germ cell tumour (TGCT), although TGCT results less frequently than in other disorders of sex development (DSD). Furthermore, the majority of detected tumoral lesions are non-invasive and with a low probability of progression into aggressive forms. Therefore, histological, epidemiological, and prognostic features of testicular cancer in CAIS allow postponing of the gonadectomy until after pubertal age in order to guarantee the initial spontaneous pubertal development and avoid the necessity of hormonal replacement therapy (HRT) induction. However, HRT is necessary after gonadectomy in order to prevent symptoms of hypoestrogenism and to maintain secondary sexual features. This article presents differential clinical presentations and management in patients with CAIS to emphasize the continued importance of standardizing the clinical and surgical approach to this disorder.

Testicular cancer among US men aged 50 years and older

BACKGROUND

The incidence of testicular cancer in the United States (US) has substantially increased in recent decades. The majority of testicular cancers are germ cell tumors (TGCT), which are the most commonly occurring malignancies among men aged 15-44 years in the US. To date, few studies have focused on testicular cancer among men aged ≥ 50 years. Thus, we sought to examine detailed descriptive features, including incidence rates and age patterns, of tumors that arise in the testes among men aged ≥ 50 years.

METHODS

Data from forty-one US cancer registries were included for the years 1999-2014. Incidence rates per 100,000 person-years and their 95% confidence intervals (CI) were calculated by race/ethnicity, histology, and age at diagnosis. Estimates of annual percent change (APC) were also calculated.

RESULTS

Age-specific incidence rates of spermatocytic tumors, sex cord stromal tumors and lymphomas rose with age, while age-specific incidence rates of seminomas and nonseminomas declined. Between 1999 and 2014, the incidence of nonseminoma (APC = 3.26, 95% CI: 2.27-4.25) increased more than any other tumor type. The incidence of seminoma (APC: 1.15, 95% CI: 0.59-1.71) also increased, while rates of testicular lymphoma (APC: -0.66, 95% CI: -1.16 to -0.16), spermatocytic tumors (APC: 0.42, 95% CI: -1.42 to 2.29), and sex cord stromal tumors (APC: 0.60, 95% CI: -3.21 to 4.55) remained relatively unchanged.

CONCLUSION

Given the distinct time-trends and age-specific patterns of testicular cancer in men aged ≥50 years, additional investigation of risk factors for these tumors is warranted.

Cross-Cancer Pleiotropic Associations with Lung Cancer Risk in African Americans

BACKGROUND

Identifying genetic variants with pleiotropic associations across multiple cancers can reveal shared biologic pathways. Prior pleiotropic studies have primarily focused on European-descent individuals. Yet population-specific genetic variation can occur, and potential pleiotropic associations among diverse racial/ethnic populations could be missed. We examined cross-cancer pleiotropic associations with lung cancer risk in African Americans.

METHODS

We conducted a pleiotropic analysis among 1,410 African American lung cancer cases and 2,843 controls. We examined 36,958 variants previously associated (or in linkage disequilibrium) with cancer in prior genome-wide association studies. Logistic regression analyses were conducted, adjusting for age, sex, global ancestry, study site, and smoking status.

RESULTS

We identified three novel genomic regions significantly associated (FDR-corrected P <0.10) with lung cancer risk (rs336958 on 5q14.3, rs7186207 on 16q22.2, and rs11658063 on 17q12). On chromosome16q22.2, rs7186207 was significantly associated with reduced risk [OR = 0.43; 95% confidence interval (CI), 0.73-0.89], and functional annotation using GTEx showed rs7186207 modifies DHODH gene expression. The minor allele at rs336958 on 5q14.3 was associated with increased lung cancer risk (OR = 1.47; 95% CI, 1.22-1.78), whereas the minor allele at rs11658063 on 17q12 was associated with reduced risk (OR = 0.80; 95% CI, 0.72-0.90).

CONCLUSIONS

We identified novel associations on chromosomes 5q14.3, 16q22.2, and 17q12, which contain HNF1B, DHODH, and HAPLN1 genes, respectively. SNPs within these regions have been previously associated with multiple cancers. This is the first study to examine cross-cancer pleiotropic associations for lung cancer in African Americans.

IMPACT

Our findings demonstrate novel cross-cancer pleiotropic associations with lung cancer risk in African Americans.

The puzzling incidence of testicular cancer in New Zealand: what can we learn?

BACKGROUND

Testicular germ cell tumour is the most common cancer to be diagnosed among young men. In New Zealand, we have observed some puzzling trends in the epidemiology of this disease.

METHODS

We have conducted a narrative review of available evidence regarding the puzzling epidemiology of testicular germ cell tumour in New Zealand and discussed the possible drivers of these trends.

RESULTS AND DISCUSSION

Whereas testicular cancer is most commonly a disease of White men, in New Zealand it is the indigenous Māori population that suffer by far the greatest rate of disease (age-adjusted relative risk: 1.80, 95% CI 1.58-2.05). Even more curiously, the rate of testicular germ cell tumour among Māori men aged 15-44 (28/100,000) is substantially greater than for Pacific Island men (9/100,000), a rare example of divergence between these two populations in terms of the incidence of any disease (cancer or otherwise). Our observations beg the following questions: first, why are rates of testicular germ cell tumour so much higher among Māori New Zealanders compared to the already high rates observed among European/Other New Zealanders? Second, why are rates of testicular germ cell tumour so completely divergent between Māori and Pacific New Zealanders, when these two groups typically move in parallel with respect to the incidence of given diseases? Finally, what might we learn about the factors that cause testicular germ cell tumour in general by answering these questions?

CONCLUSION

This review examines the possible drivers of our observed disparity, discusses their feasibility, and highlights new work that is underway to further understand these drivers.

Human Germ Cell Tumors are Developmental Cancers: Impact of Epigenetics on Pathobiology and Clinic

Current (high throughput omics-based) data support the model that human (malignant) germ cell tumors are not initiated by somatic mutations, but, instead through a defined locked epigenetic status, representative of their cell of origin. This elegantly explains the role of both genetic susceptibility as well as environmental factors in the pathogenesis, referred to as 'genvironment'. Moreover, it could also explain various epidemiological findings, including the rising incidence of this type of cancer in Western societies. In addition, it allows for identification of clinically relevant and informative biomarkers both for diagnosis and follow-up of individual patients. The current status of these findings will be discussed, including the use of high throughput DNA methylation profiling for determination of differentially methylated regions (DMRs) as well as chromosomal copy number variation (CNV). Finally, the potential value of methylation-specific tumor DNA fragments (i.e., XIST promotor) as well as embryonic microRNAs as molecular biomarkers for cancer detection in liquid biopsies will be presented.

Testicular Cancer: Genes, Environment, Hormones

Testicular cancer (TC) represents one of the most peculiar clinical challenges at present. In fact, currently treatments are so effective ensuring a 5 years disease-free survival rate in nearly 95% of patients. On the other hand however, TC represents the most frequent newly diagnosed form of cancer in men between the ages of 14 and 44 years, with an incidence ranging from <1 to 9.9 affected individuals per 100,000 males across countries, while the overall incidence is also increasing worldwide. Furthermore, cancer survivors show a 2% risk of developing cancer in the contralateral testis within 15 years of initial diagnosis. This complex and multifaceted scenario requires a great deal of effort to understand the clinical base of available evidence. It is now clear that genetic, environmental and hormonal risk factors concur and mutually influence both the development of the disease and its prognosis, in terms of response to treatment and the risk of recurrence. In this paper, the most recent issues describing the relative contribution of the aforementioned risk factors in TC development are discussed. In addition, particular attention is paid to the exposure to environmental chemical substances and thermal stress, whose role in cancer development and progression has recently been investigated at the molecular level.

Malignant testicular germ cell tumors in postpubertal individuals with androgen insensitivity: prevalence, pathology and relevance of single nucleotide polymorphism-based susceptibility profiling

STUDY QUESTION

What is the prevalence of malignant testicular germ cell tumors (TGCT) and its precursors, (pre-) germ cell neoplasia in situ (GCNIS), in late teenagers and adults who have androgen insensitivity syndrome (AIS) and the impact of an individual's genetic susceptibility to development of TGCT?

SUMMARY ANSWER

No GCNIS or TGCT was diagnosed, but pre-GCNIS was identified in 14 and 10% of complete and partial AIS patients, respectively, and was associated with a higher genetic susceptibility score (GSS), with special attention for KITLG (rs995030) and ATFZIP (rs2900333).

WHAT IS KNOWN ALREADY

Many adult women with AIS decline prophylactic gonadectomy, while data regarding the incidence, pathophysiology and outcomes of TGCT in postpubertal individuals with AIS are lacking. The relevance of genetic factors, such as single nucleotide polymorphisms (SNPs), in predisposing AIS individuals to TGCT is unknown.

STUDY DESIGN, SIZE, DURATION

This multicenter collaborative study on prophylactically removed gonadal tissue was conducted in a pathology lab specialized in germ cell tumor biology.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Material from 52 postpubertal individuals with molecularly confirmed AIS (97 gonadal samples) was included; the median age at surgery was 17.5 (14-54) years. Immunohistochemical studies and high-throughput profiling of 14 TGCT-associated SNPs were performed. The main outcome measures were the prevalence of pre-GCNIS, GCNIS and TGCT, and its correlation with a GSS, developed based on the results of recent genome-wide association studies.

MAIN RESULTS AND ROLE OF CHANCE

The earliest recognizable change preceding GCNIS, referred to as pre-GCNIS, was present in 14% of individuals with complete and 10% of those with partial AIS at a median age of 16 years. No GCNIS or invasive TGCT were found. The median GSS was significantly greater for those with, compared to those without, pre-GCNIS (P = 0.01), with an overlap between groups. Our data suggest important roles for risk alleles G at KITLG (rs995030) and C at ATFZIP (rs2900333), among the 14 studied TGCT-associated SNPs.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

A limited number of cases were included.

WIDER IMPLICATIONS OF THE FINDINGS

Our data suggest that the prevalence of pre-GCNIS in individuals with AIS beyond puberty is around 15%. Genetic susceptibility likely contributes to pre-GCNIS development in AIS but factors related to malignant progression remain unclear. Although data in older patients remain scarce, malignant progression appears to be a rare event, although the natural history of the premalignant lesion remains unknown. Therefore, the practice of routine prophylactic gonadectomy in adults with AIS appears questionable and the patient's preference, after having been fully informed, should be decisive in this matter.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by research grants from the Research Foundation Flanders (FWO) (to M.C.), the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq G0D6713N) (to B.B.M. and M.C.) and the European Society for Pediatric Endocrinology (ESPE), granted by Novo Nordisk AB (to J.K.). There are no competing interests.

Testicular cancer

Testicular cancer is the most common malignancy among men between 14 and 44 years of age, and its incidence has risen over the past two decades in Western countries. Both genetic and environmental factors contribute to the development of testicular cancer, for which cryptorchidism is the most common risk factor. Progress has been made in our understanding of the disease since the initial description of carcinoma in situ of the testis in 1972 (now referred to as germ cell neoplasia in situ), which has led to improved treatment options. The combination of surgery and cisplatin-based chemotherapy has resulted in a cure rate of >90% in patients with testicular cancer, although some patients become refractory to chemotherapy or have a late relapse; an improved understanding of the molecular determinants underlying tumour sensitivity and resistance may lead to the development of novel therapies for these patients. This Primer provides an overview of the biology, epidemiology, diagnosis and current treatment guidelines for testicular cancer, with a focus on germ cell tumours. We also outline areas for future research and what to expect in the next decade for testicular cancer.

Expression analysis of genes encoding TEX11, TEX12, TEX14 and TEX15 in testis tissues of men with non-obstructive azoospermia

Objective

Spermatogenesis is a complex process controlled by a plethora of genes. Changes in expression and function of these genes may thus lead to spermatogenic deficiency and male infertility. TEX11, TEX12, TEX14 and TEX15 are germ cell-specific genes expressed in the testis. TEX11, involved in the initiation and maintenance of chromosome synapses in meiotic chromosomes, has been shown to be essential for meiosis and fertility in males. TEX14, a component of intercellular bridges in germ cells, is required for spermatogenesis and fertility. TEX12 and TEX15 are essential for correct assembly of the synaptonemal complex and thus meiosis progression.

Methods

In order to examine whether changes in expression of these genes is associated with impaired spermatogenesis, expression levels of these genes were quantified by RT-qPCR on samples retrieved from infertile patients submitted to diagnostic testicular biopsy at Royan institute. Samples were divided into two groups of 18 patients with non-obstructive azoospermia considered as case; nine patients with obstructive azoospermia were included in the control group.

Results

A significant down-regulation of these genes was observed in the SCOS group when compared to the control group.

Conclusion

This result suggests that regular expression of TEX11, TEX12, TEX14 and TEX15 is essential for the early stages of spermatogenesis.

Testicular Cancer in New Zealand (TCNZ) study: protocol for a national case-control study

Testicular cancer (TC) is by far the most common cancer to affect young men; however, the exposures that cause this disease are still poorly understood. Our own research has shown that Māori men have the highest rates of this disease in New Zealand-a puzzling observation, since internationally TC is most commonly a disease of men of European ancestry. These trends provide us with a unique opportunity: to learn more about the currently unknown exposures that cause TC, and to explain why Māori have the highest rates of this disease in New Zealand. Using epidemiology and genetics, our experienced research team will conduct a nationwide study which aims to answer these internationally important questions.

AIM OF STUDY

The overall aim of the current national case-control study is to identify the key exposures in the development of TC in New Zealand, and explore which factors might explain the difference in the incidence of TC between Māori and non-Māori.

METHODS AND ANALYSIS

Outside of our own investigations into cryptorchidism, we still do not know which exposures are driving the significant incidence disparity between ethnic groups in NZ. The aim of the proposed research is to use a population-based case-control study to identify the key exposures in the development of TC in New Zealand. We will recruit 410 TC cases and 410 controls, and collect (1) environmental exposure data, via interview and (2) genetic information, via genome-wide genotyping.

ETHICS AND DISSEMINATION

Ethical approval for this study was sought and received from the New Zealand Ministry of Health's Health and Disability Ethics Committee (reference # 17/NTA/248). Following a careful data interpretation process, we will disseminate the findings of this study to a wide and varied audience ranging from general academia, community groups and clinical settings, as well as to the participants themselves.

Genomic Characterization of Testicular Germ Cell Tumors Relapsing After Chemotherapy

BACKGROUND

Although both seminomatous and nonseminomatous testicular germ cell tumors (TGCTs) have favorable outcomes with chemotherapy, a subset is chemorefractory, and novel therapeutic options are needed.

OBJECTIVE

To molecularly characterize chemotherapy-refractory TGCTs.

DESIGN, SETTING, AND PARTICIPANTS

Archival tissues from 107 chemotherapy-treated and relapsed TGCT patients (23 seminomas; 84 nonseminomas) underwent hybrid-capture-based genomic profiling to evaluate four classes of genomic alterations (GAs). Tumor mutational burden (TMB) and microsatellite instability (MSI) were also measured.

INTERVENTION

Genomic profiling on tumor samples from chemotherapy-refractory TGCTs.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Descriptive analyses and differences between seminoma and nonseminoma subgroups were reported.

RESULTS AND LIMITATIONS

The mean GA/tumor was 2.9 for seminomas and 4.0 for nonseminomas (p=0.04). KRAS alterations (mainly amplifications) were the most common GAs at the single-gene level (47.8% of seminomas and 51.2% of nonseminomas). RAS-RAF pathway (56.5% vs 52.3%) and cell-cycle pathway (52.2% vs 56.0%) were the most common GA classes in seminomas and nonseminomas, respectively. Receptor tyrosine kinase pathway and PI3K pathway GAs were more frequent in seminomas (p=0.02). Median TMB was 1.8 mutations/Mb for seminomas and 2.7 mutations/Mb for nonseminomas (p=0.098), and MSI-high status was found in one nonseminoma only (1.2%). A lack of clinical outcome correlation is a limitation of the present analyses.

CONCLUSIONS

In chemotherapy-refractory TGCTs, trials with agents targeting the KRAS pathway may be pursued due to the high frequency of KRAS GAs. Overall, the GAs found in refractory seminomas and nonseminomas differ significantly. Considering the frequency of high TMB or MSI-high status, immunotherapy may benefit a small subset of nonseminomas.

PATIENT SUMMARY

Testicular cancers that are resistant to or relapse after standard chemotherapy may harbor genomic alterations that are potentially druggable, particularly in the clinical trial setting, and genomic profiling can guide clinical research and disclose therapeutic opportunities for these patients.

Genome-wide association study identifies the GLDC/IL33 locus associated with survival of osteosarcoma patients

Survival rates for osteosarcoma, the most common primary bone cancer, have changed little over the past three decades and are particularly low for patients with metastatic disease. We conducted a multi-institutional genome-wide association study (GWAS) to identify germline genetic variants associated with overall survival in 632 patients with osteosarcoma, including 523 patients of European ancestry and 109 from Brazil. We conducted a time-to-event analysis and estimated hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional hazards models, with and without adjustment for metastatic disease. The results were combined across the European and Brazilian case sets using a random-effects meta-analysis. The strongest association after meta-analysis was for rs3765555 at 9p24.1, which was inversely associated with overall survival (HR = 1.76; 95% CI 1.41-2.18, p = 4.84 × 10-7 ). After imputation across this region, the combined analysis identified two SNPs that reached genome-wide significance. The strongest single association was with rs55933544 (HR = 1.9; 95% CI 1.5-2.4; p = 1.3 × 10-8 ), which localizes to the GLDC gene, adjacent to the IL33 gene and was consistent across both the European and Brazilian case sets. Using publicly available data, the risk allele was associated with lower expression of IL33 and low expression of IL33 was associated with poor survival in an independent set of patients with osteosarcoma. In conclusion, we have identified the GLDC/IL33 locus on chromosome 9p24.1 as associated with overall survival in patients with osteosarcoma. Further studies are needed to confirm this association and shed light on the biological underpinnings of this susceptibility locus.

Systematic review and meta-analysis of the genetic association between protamine polymorphism and male infertility

While several previous studies have proposed an association between male infertility and protamine polymorphism, the reported findings have shown some inconsistency. To evaluate the potential association between the two most common single nucleotide polymorphisms (rs2301365 and rs1646022) in protamine and male infertility, we performed a meta-analysis involving 2713 cases and 2086 controls from 15 published case-controlled studies. Overall, our analysis showed significant associations between the specific protamine single-nucleotide polymorphism (rs2301365) and male infertility, and this association was indicated by all of the models we tested. Subgroup analysis revealed significant associations with a Caucasian background, PCR sequence, population-based, case size of > 150 and case size of < 150 subgroups. Similarly, significant associations were found between rs1646022 and male infertility in the hospital population and case size of < 200 subgroups. However, trial sequential analysis showed that the number of patients in the study did not reach optimal information size. Further studies with larger sample sizes are now warranted to clarify the potential roles of the two protamine polymorphisms in the pathogenesis of male infertility. This may help us to understand the precise molecular mechanisms underlying the effect of protamines upon male infertility.