Testicular germ cell tumours

Prenatal exposure to organochlorine pesticides and polychlorinated biphenyls and risk of testicular germ cell cancer later in life

INTRODUCTION

Exposure to environmental chemicals during fetal development may increase the risk of testicular germ cell cancer (TGCC), but few studies have tested the hypothesis. We focused on organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), previously investigated in relation to other male reproductive health outcomes.

METHODS

We conducted a nested case-control study of 332 mother-son pairs, comprising 65 TGCC cases and 267 controls, identified from a Danish Pregnancy Screening Registry with biobanked serum samples collected from pregnant women in 1985-1995, when exposure to the studied chemicals was relatively high. We quantified seven OCPs and 13 PCB congeners in maternal serum by gas chromatography tandem mass spectrometry. TGCC diagnoses and covariate information were derived from the nationwide Danish registries. We estimated associations between individual chemicals and their mixture with the risk of TGCC through adapted Cox regression and quantile g-computation models.

RESULTS

Median age at TGCC diagnosis was 24.7 years. In main analyses, associations between individual OCPs and PCBs and risk of TGCC showed either slightly higher risks or no association (close to Hazard Ratios (HR) of 1.00), with confidence intervals overlapping unity. In mixture analyses, simultaneously increasing all chemical concentrations by one quartile resulted in a slightly higher risk of TGCC (HR 1.11, 95 % CI: 0.61; 2.05) after adjusting for confounders. Sensitivity analyses investigating tertiles of concentrations did not change the overall pattern of results.

CONCLUSIONS

Prenatal exposure to OCPs and PCBs, quantified by concentrations in maternal pregnancy serum, was not associated with later risk of TGCC.

Testicular Germ Cell Tumors: A Review

Importance

Testicular cancer is the most common solid malignancy among males aged 15 to 40 years in the US, with approximately 10 000 new cases diagnosed each year. Between 90% and 95% of testicular cancers are germ cell tumors (GCTs).

Observations

The mean age at diagnosis for testicular cancer is 33 years. GCTs are categorized as seminomas and nonseminomatous GCTs (NSGCTs) based on their embryonic origins and path of differentiation. Risk factors include cryptorchidism, family history of testicular cancer, gonadal dysgenesis, infertility, cannabis use, and genetic conditions such as Klinefelter syndrome. The most common presenting symptom of testicular cancer is a painless testicular mass. History, physical examination, scrotal ultrasound, laboratory assessment of GCT-associated serum tumor markers (α-fetoprotein, β-human chorionic gonadotropin, and lactate dehydrogenase), and prompt referral to a urologist are indicated when testicular cancer is suspected. Early diagnosis and treatment, starting with a radical inguinal orchiectomy, are important to optimize outcomes. At diagnosis, GCT is stage I (localized to the testicle) in 70% to 75% of patients, stage II (metastatic only to the retroperitoneal lymph nodes) in 20%, and stage III (widely metastatic) in 10%. Treatment of GCTs is guided by histology, clinical staging, and risk classification, with 5-year survival rates of 99%, 92%, and 85% for those diagnosed at stages I, II, and III, respectively. Optimal treatment often involves a multidisciplinary team at high-volume, experienced medical centers and may include surveillance (serum tumor markers [α-fetoprotein, β-human chorionic gonadotropin, and lactate dehydrogenase] and imaging of the chest, abdomen, and pelvis), surgery (retroperitoneal lymph node dissection), chemotherapy, and/or radiation. Treatment decisions should consider long-term survivorship concerns, including body image, fertility, hypogonadism, mental health, financial cost, adherence to follow-up, and late adverse effects of therapy such as cardiovascular disease, secondary malignancies, and potential psychosocial effects such as anxiety, depression, and social isolation.

Conclusions and Relevance

Testicular cancer is the most common solid malignancy in young men in the US, and 90% to 95% are GCTs. Patients with testicular GCT have a 5-year survival rate of 99%, 92%, and 85% for stages I, II, and III, respectively. Prompt diagnosis and treatment are important to optimize outcomes, and treatment decisions should balance oncologic control with survivorship concerns to minimize long-term adverse effects of treatment.

Testicular ultrasonographic features predict future risk for bilateral testicular germ cell tumour: A long-term single centre follow-up study

BACKGROUND

Bilateral testicular germ cell tumours (B-GCT) are rare, with an incidence of 2-5%, and can be classified as synchronous (sB-GCT) or metachronous (mB-GCT). Our study aimed to identify clinical, biochemical, and radiological risk factors for mB-GCT in a cohort of patients with GCT at a single tertiary referral centre.

METHODS

This retrospective case-control study included patients with GCT referred to Policlinico Umberto I-Sapienza University of Rome, from 2005 to 2023. We evaluated clinical history, testicular ultrasound features, hormone levels, semen analysis, histological characteristics, staging, and treatments. mB-GCTs were compared with unilateral GCT patients with a follow-up longer than the median time-to-onset of the second tumour.

RESULTS

Of 319 patients, 52 experienced B-GCT, with a median time-to-onset of the second tumour of 62 months (range: 8-229). The mB-GCT group showed higher gonadotropin levels (FSH 13.6mUI/mL vs. 7.4mUI/mL, p < 0.001; LH 6.6mUI/mL vs. 3.9mUI/mL, p = 0.004), lower sperm concentration (27 × 106/ejaculate vs. 78 × 106/ejaculate, p = 0.009), smaller residual testis volume (10.4 mL vs. 16.3 mL, p < 0.001), more inhomogeneous echotexture [57.5% vs. 14%, p < 0.001], and presence of microlithiasis (75% vs. 19.5%, p < 0.001). Kaplan-Meier curves confirmed that ultrasound features of the residual testis increased the cumulative risk of developing a second tumour. Microlithiasis was a strong independent predictor (OR 30.712, 95% CI 3.357-280.942, p = 0.002).

CONCLUSIONS

Histological features of the first tumour or its treatment do not influence the onset of a second tumour. However, low residual testis volume, inhomogeneous echotexture, and microlithiasis significantly increase this risk. A comprehensive evaluation of the residual testis at baseline is essential for developing a personalised surveillance programme in GCT survivors, with regular ultrasound follow-up recommended beyond the conventional 5-year limit.

Post-Chemotherapy Retroperitoneal Lymph Node Dissection for Metastatic Testicular Cancer at a National Referral Centre

OBJECTIVE

To assess the safety of open PC-RPLND at a high-volume national referral centre over the course of several years.

MATERIALS AND METHODS

A retrospective chart review of patients with testicular germ cell tumours (TGCTs) who underwent PC-RPLND at our institution between 2008 and 2023 was conducted. Patient demographics, clinical characteristics, intraoperative and postoperative parameters and adjunctive procedures were recorded. ClassIntra and Clavien Dindo classifications were used to assess intraoperative and postoperative complications, respectively.

RESULTS

In total, 165 patients were studied. The median (Q1-Q3) age of patients was 30.5 years (24.75-38.25), and the median maximum diameter of retroperitoneal masses was 50 mm (26.75-81.25). The most common adjunctive procedure was synchronous nephrectomy (n = 18, 11%) followed by vascular procedures (n = 7, 4.3%), ureteric reconstruction (n = 7, 4.3%), and partial hepatectomy (n = 3, 1.9%). Intraoperatively, 20, 8 and 1 patient had a grade I, II or V complication, respectively, according to the ClassIntra classification. The median estimated blood loss was 300 mL (120-740), the median duration of the procedure was 4.9 h (4-6 h) and the median length of stay was 8 days (7-10 days). Histopathological examination of the resected specimen showed teratoma in 51.9% of patients, followed by fibrosis/necrosis in 39.5%. A total of 40 patients (24.7%) experienced at least one complication.

CONCLUSIONS

PC-RPLND is a complex operation, often accompanied by adjunctive surgical procedures and therefore must be conducted in high-volume referral centres to ensure safety and minimise complications.

Follow-up of non-palpable testicular incidentalomas under 1 cm: does growth rate differentiate malignant and non-malignant lesions?

OBJECTIVE

To determine whether small, incidentally detected testicular lesions can be safely followed up, by assessing growth rate and volume threshold for benign vs. malignant lesions.

METHODS

This retrospective observational study includes a consecutive series of 130 testicular incidentalomas < 1 cm and with negative tumour markers identified from October 2001 to November 2022, which were initially followed up with ultrasound. A total of 39 cases proceeded to surgery during the study period, either due to lesion growth (n = 28) or patient preference/recommendation by the referring urologist (n = 11). For the lesions that were growing, specific growth rate (SGR) and doubling time (DT) were calculated assuming an exponential growth pattern. In addition, the velocity of increase of the average diameter (∆Dav) and of the maximum diameter (∆Dmax) were calculated.

RESULTS

Of the 130 nodules that were initially followed up, six disappeared, eight were reduced in size, eighty-eight were stable, and twenty-eight increased in size. For operated nodules all 18 malignant tumours, 8/9 benign tumours, and 2/12 surgically proved non-neoplastic lesions were growing. The best cut-off values of the growth indicators to differentiate between malignant and non-malignant histology were 3.47 × 10-3%volume/day, ≤ 179 days, > 10 × 10-3 mm/day, and > 5 × 10-3 mm/day for SGR, DT, ∆Dmax, ∆Dav, respectively.

CONCLUSIONS

Malignant and non-malignant small incidentalomas can be effectively differentiated based on growing parameters, even though overlap exists. An increase of the maximum diameter of about 1 mm and 2 mm in three months and in six months, respectively, suggests malignancy.

CLINICAL RELEVANCE STATEMENT

Growing parameters allow an educated assessment of benign and malignant small testicular incidentalomas. Non-aggressive management is justified and safe when follow-up includes self-examination and tumour marker assessment to reduce the risk of interval tumour growth.

KEY POINTS

Small, non-palpable and asymptomatic testicular nodules < 1 cm are unexpectedly discovered during scrotal ultrasound. Growth indicators estimate the potential malignancy, even though overlap with non-malignant lesions exists. Non-growing incidentalomas can be safely followed up.

Exploring the microbiome-gut-testis axis in testicular germ cell tumors

The microbiome-gut-testis axis has emerged as a significant area of interest in understanding testicular cancer, particularly testicular germ cell tumors (TGCTs), which represent the most common malignancy in young men. The interplay between the gut and testicular microbiomes is hypothesized to influence tumorigenesis and reproductive health, underscoring the complex role of microbial ecosystems in disease pathology. The microbiome-gut-testis axis encompasses complex interactions between the gut microbiome, systemic immune modulation, and the local microenvironment of the testis. Dysbiosis in the gut or testicular microbiomes may contribute to altered immune responses, inflammation, and hormonal imbalances, potentially playing a role in the pathogenesis of TGCTs. Concurrently, seminal microbiomes have been linked to variations in sperm quality, fertility potential, and possibly cancer susceptibility, underscoring the need for further evaluation. This review explores the emerging role of the microbiome-gut-testis axis in the context of testicular cancer, highlighting its implications for disease onset, progression, treatment efficacy, and toxicity. Identifying potential microbial biomarkers, followed by microbiota modulation to restore a balanced microbial community, might offer a novel supportive strategy for improving treatment efficacy in refractory TGCT patients while reducing chemotherapy-induced toxicity. We suggest a better understanding of the association between dysregulated microbial environments and TGCTs emphasizes potential pathways by which the gut microbiome might influence testicular cancer.

Global burden and trends of testicular cancer in adolescents and young adults from 1990 to 2021, with predictions to 2035

Testicular cancer predominantly affects adolescents and young adults (AYAs) aged 15-39 years. This study analyzed the global, regional, and national burden of testicular cancer among AYAs (1990 to 2021). Data from the Global Burden of Disease study was used to calculate age-standardized rates of incidence (ASIR), prevalence (ASPR), and disability-adjusted life years (ASDR). Trends were assessed using the Joinpoint regression and Bayesian age-period-cohort models, with projections up to 2035. Results showed the global ASIR of 4.05 (95% CI: 3.80-4.35), ASPR of 31.05 (95% CI: 28.88-33.68), and ASDR of 24.82 (95% CI: 22.99-26.91) per 100,000 in 2021, respectively. From 1990 to 2021, ASIR and ASPR increased, while ASDR remained relatively stable. Significant geographical disparities were observed, with Europe and Latin America showing higher burdens compared to Asia and Africa. The 25-29 age group had the highest age-specific rate of incidence (5.58; 95% UI: 5.25-5.97) and disability-adjusted life years (34.09; 95% UI: 31.55-37.11) per 100,000, while the 30-34 age group had the highest age-specific prevalence rate (43.12; 95% UI: 40.51-46.56) per 100,000 in 2021. By 2035, the global numbers of incidence and prevalence cases were projected to increase, with DALYs and age-standardized rates declining. These findings are crucial for informing global strategies in testicular cancer prevention.

Teratoma Development in 129.MOLF-Chr19 Mice Elicits Two Waves of Immune Cell Infiltration

Teratomas are a highly differentiated type of testicular germ cell tumors (TGCTs), the most common type of solid cancer in young men. Prominent inflammatory infiltrates are a hallmark of TGCTs, although their compositions and dynamics in teratomas remain elusive. Here, we reached out to characterize the infiltrating immune cells and their activation and polarization state by using high-throughput gene expression analysis of 129.MOLF-Chr19 mice that spontaneously develop testicular teratomas. We showed that inconspicuous testes without any apparent alterations in size or morphology can be clustered into three groups based on their expression of stemness and immune genes, supporting a model in which initial oncogenic transformation elicits a first wave of T-cell infiltration. Moderately and severely enlarged tumorous testes then displayed a progressive infiltration with T cells, monocytes/macrophages, and B cells. Importantly, T cells seem to adopt an inactive state caused by an overexpression of immune checkpoint molecules and the polarization of monocytes/macrophages to an anti-inflammatory phenotype. Our findings are supported by the analysis of metabolic gene expression, which unveiled alterations indicative of tumor growth and immune cell infiltration. Collectively, testicular teratomas, at least in mice, are characterized by a diverse inflammatory infiltrate containing T cells that putatively become inactivated, allowing the tumors to further grow. We believe that these findings may provide a rationale for the development of new immunomodulatory therapies for TGCTs.

A Unique Case of Bilateral Testicular Tumours: Nonseminomatous Germ Cell Tumour and Contralateral Spermatocytic Tumour 27 Years Apart

INTRODUCTION

Bilateral testicular tumours occur in 3-5% of all cases with testicular neoplasms. In the majority of cases, histology of the two new growths is identical. The time interval between the two neoplastic events rarely exceeds 10 years.

CASE PRESENTATION

A 29-year-old man of Caucasian descent underwent right-sided orchiectomy for a nonseminomatous germ cell tumour (GCT). Postoperatively, he received adjuvant chemotherapy with 2 cycles of a cisplatin based regimen for clinical stage 1 disease. Twenty-seven years later when aged 56 years, he developed a lump in the left testis. Serum tumour markers including microRNA-371a-3p were within normal limits. Orchiectomy was performed. Histology revealed a spermatocytic tumour with positive stainings of SALL4, NUT, and CD117. No germ cell neoplasia in situ (GCNis) was detected in the tumour-surrounding tissue.

CONCLUSION

Histogenetically, testicular GCTs are thought to derive from the precursor GCNis, while spermatocytic tumours directly derive from adult spermatogonia. This case is exceptional, firstly because of the very long interval of 27 years between the two neoplastic events, and secondly because of the unprecedented occurrence of two testicular neoplasms with different pathogenetic origins in 1 individual patient.

Understanding the role of endocrine disrupting chemicals in testicular germ cell cancer: Insights into molecular mechanisms

This comprehensive review examines the complex interplay between endocrine disrupting chemicals (EDCs) and the development of testicular germ cell tumors (TGCTs). Despite the high cure rates of TGCTs, challenges in diagnosis and treatment remain, necessitating a deeper understanding of the etiology of the disease. Here, we emphasize current knowledge on the role of EDCs as potential risk factors for TGCTs, focusing on pesticides and perfluorinated and polyfluoroalkyl substances (PFAs/PFCs). Evidence suggests that EDCs disrupt endocrine pathways and induce epigenetic changes that contribute to the development of TGCTs. However, the direct link between EDCs and TGCTs remains elusive and requires further investigation of the molecular mechanisms. We also highlighted the importance of studying nuclear receptors as potential targets for understanding TGCT etiology. In addition, recent evidence implicates PFAs/PFCs in TGCT incidence, highlighting the need for further research into their impact on human health. Overall, this review provides valuable insights into the potential role of EDCs in TGCT development and suggests avenues for future research, while also highlighting how understanding their influence may pave the way for novel therapeutic approaches to improve disease management.

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.

Contemporary Role of Radiation Therapy in Testicular Cancer

Testicular cancer is a rare but curable male malignancy. Seminoma represents the majority of germ cell tumors and is considered radiation sensitive. Radiation treatment plays a role in adjuvant therapy after orchiectomy of stage I, IIA, and IIB seminomas. Radiation dose de-escalation has been effective in preventing tumor recurrences while also limiting acute and long-term toxicities. However, long-term risks, including the prevailing concern of secondary malignancy risk, between adjuvant radiation and chemotherapy play a role in recommendations. Ongoing work continues to be performed to reduce radiation field and dose in combination with chemotherapy while still maintaining excellent outcomes.

Extragonadal Germ Cell Tumors: A Single Institution Experience with Clinicopathological Correlation

Background. Extragonadal germ cell tumors (EGCTs) are a rare heterogeneous group of tumors without evidence of primary gonadal germ cell tumors. They account for 2%-5% of overall malignancies. EGCTs are often not clinically suspected, making them challenging for pathologists. In this retrospective observational study, we describe our institutional experience among EGCTs with clinicopathological correlation. Materials and methods. All patients diagnosed as EGCTs from January 2014 to April 2023 were collected. All relevant clinical data and serum markers were retrieved from hospital medical records. Histopathology and immunohistochemistry slides were reviewed. Results. The present study included a total of 56 patients; 34 (60%) men and 22 (40%) women with a men-to-women ratio of 1.5:1. Of them, 1 patient had congenital/neonatal EGCTs, 21 patients had prepubertal EGCTs, and 34 had post-pubertal EGCTs. The common sites included are mediastinum (45%), sacrococcyx (18%), retroperitoneum (14%), and central nervous system (12%). The other rare sites were the vagina, liver, colon, and duodenum. The common germ cell tumor included mature teratoma (34%), mixed germ cell tumor (27%), seminoma/germinoma (12%), pure yolk sac tumor (11%), immature teratoma (9%), mature teratoma with somatic tumor (5%), and embryonal carcinoma (2%). All histological diagnoses of germ cell tumors were confirmed with IHC markers like PLAP, CD117 (KIT), AFP, LIN28, CD30, and β-hCG. Pre and posttreatment serum tumor marker levels were available in 37 patients. All our treated patients had a decrease or normal tumor marker levels post-therapy. Conclusion. In our study, a heterogeneous group of germ cell tumors was seen. Most of them were seen in post-pubertal adolescents and young adults. Early intervention by platinum-based combination chemotherapy in seminoma and nonseminomatous germ cell tumors has significantly improved the prognosis of malignant EGCTs similar to their germ cell counterparts.

RAISN: Robot-assisted Indocyanine Green-guided Sentinel Node Biopsy in Clinical Stage I Germ Cell Tumor

Robot-assisted imaging-guided sentinel lymph node biopsy is a novel technique that has not been widely investigated in testicular germ cell tumor (GCT). Current staging strategies have poor accuracy for prediction of occult metastatic disease in clinical stage I GCT. Feasibility studies have used 99mTc-nanocolloid staining during laparoscopic procedures. The RAISN trial is investigating robot-assisted lymph node resection guided by indocyanine green fluorescence imaging. This new diagnostic approach is potentially more precise and easier to apply, and is widely available. Confirmation of its utility could change the management of newly diagnosed GCT by reducing overtreatment and treatment-related toxicity.

Malignant ovarian and testicular germ cell tumors: Common characteristics but different prognoses

Both ovarian and testicular germ cell tumors (GCTs) arise from the primordial germ cell and share many similarities. Both malignancies affect mainly young patients, show remarkable responsiveness to cisplatin-based therapy, and have an excellent prognosis, which also highlights the importance of minimizing long-term side effects. However, certain differences can be noted: The spreading of the disease differs, and the staging system and treatment recommendations are dissimilar. Moreover, the prognosis for ovarian GCTs is significantly inferior to that for testicular cancer, as exemplified in this review comparing the survival in Swedish patients diagnosed with testicular (1995-2022) and ovarian (1990-2018) GCTs. The 5-year overall survival in ovarian GCTs was 85.2%, versus 98.2% for testicular GCTs. How can this be explained? One reason may be the difference in knowledge, experience, and evidence because the incidence rate of testicular cancer is more than 15 times that of ovarian GCTs. Given the rarity of the disease in women and the lack of established guidelines, a comprehensive understanding of the disease and treatment decisions is challenging. The main objective of this review is to derive insights from testicular GCTs (seminoma and non-seminoma) by reviewing etiological, tumor biological, and clinical knowledge, and to thereafter suggest actions for ovarian GCTs based on this. We hypothesize that by adopting specific treatment strategies from testicular GCTs-including de-escalating adjuvant chemotherapy for low-risk patients and implementing more standardized and intensive treatment protocols in cases of relapse-we can improve the prognosis and minimize long-term side effects in ovarian GCT patients.

T cells in testicular germ cell tumors: new evidence of fundamental contributions by rare subsets

BACKGROUND

Immune cell infiltration is heterogeneous but common in testicular germ cell tumors (TGCT) and pre-invasive germ cell neoplasia in situ (GCNIS). Tumor-infiltrating T cells including regulatory T (Treg) and follicular helper T (Tfh) cells are found in other cancer entities, but their contributions to TGCT are unknown.

METHODS

Human testis specimens from independent patient cohorts were analyzed using immunohistochemistry, flow cytometry and single-cell RNA sequencing (scRNA-seq) with special emphasis on delineating T cell subtypes.

RESULTS

Profound changes in immune cell composition within TGCT, shifting from macrophages in normal testes to T cells plus B and dendritic cells in TGCT, were documented. In most samples (96%), the CD4+ T cell frequency exceeded that of CD8+ cells, with decreasing numbers from central to peripheral tumor areas, and to tumor-free, contralateral testes. T cells including Treg and Tfh were most abundant in seminoma compared to mixed tumors and embryonal carcinoma.

CONCLUSION

Despite considerable heterogeneity between patients, T cell subtypes form a key part of the TGCT microenvironment. The novel finding of rare Treg and Tfh cells in human testis suggests their involvement in TGCT pathobiology, with implications for understanding tumor progression, to assess patients' prognosis, and as putative targets for personalized immunotherapy.

Extragonadal germ cell tumors: A clinicopathologic study with emphasis on molecular features, clinical outcomes and associated secondary malignancies

Extragonadal germ cell tumors (EGCTs) are rare, representing <5% of all germ cell tumors (GCTs). Whilst EGCTs share morphological and immunohistochemical features with their gonadal counterparts, they tend to be more aggressive and are frequently associated with secondary somatic malignancies. The aim of our study was to evaluate the clinical, morphological and immunohistochemical features, and to analyze tumors for chromosomal abnormalities of 12p, in addition to any novel genetic alterations, in a series of EGCTs. Seventy-seven EGCTs were included. Anterior mediastinum was the most common anatomic site, followed by central nervous system, retroperitoneum, sacroccygeal area, and neck. Whole genome SNP array identified isochromosome 12p in 26% of tumors. Additional cytogenetic abnormalities included the presence of gain of chr 21 in 37% of tumors. Somatic-type malignancies were identified in 8% of patients. Disease progression (metastasis and/or recurrence) was documented in 8 patients, most of whom died from their relapse. Three patients who died of disease had somatic-type malignancies. Mediastinal seminomas had a significantly better overall survival when compared to mediastinal non-seminomatous GCTs. Our study demonstrates that EGCTs share similar histologic features, but diverse clinical outcomes compared to their gonadal counterparts. Outcomes vary according to anatomic location and histologic subtypes. Our data corroborate that somatic-type malignancies are frequently encountered in mediastinal EGCTs and that their presence portends a poorer prognosis.

Expression of CD44 is associated with aggressiveness in seminomas

BACKGROUND

Testicular germ cell tumors (TGCTs) exhibit diverse biological and pathological features and are divided in two main types, seminomas and nonseminomatous germ cell tumors (NSGCTs). CD44 is a cell surface receptor, which is highly expressed in malignancies and is implicated in tumorigenesis affecting cell-matrix interactions and cell signaling.

METHODS AND RESULTS

Here, we examined the expression of CD44 in tumor cell lines and in patients' material. We found that CD44 is over-expressed in TGCTs compared to normal tissues. Immunohistochemical staining in 71 tissue specimens demonstrated increased expression of CD44 in some patients, whereas CD44 was absent in normal tissue. In seminomas, a high percentage of tumor and stromal cells showed cytoplasmic and/or cell surface staining for CD44 as well as increased staining for CD44 in the tumor stroma was found in some cases. The increased expression of CD44 either in tumor cells or in stromal components was associated with tumor size, nodal metastasis, vascular/lymphatic invasion, and disease stage only in seminomas. The increased stromal expression of CD44 in TGCTs was positively associated with angiogenesis.

CONCLUSIONS

CD44 may exhibit diverse biological functions in seminomas and NSGCTs. The expression of CD44 in tumor cells as well as in tumor stroma fosters an aggressive phenotype in seminomas and should be considered in disease treatment.

Competing risk nomogram predicting cause-specific mortality in older patients with testicular germ cell tumors

Background

Testicular germ cell tumor (TGCT) is the most common type of malignancy in young men, but rarely in older adults. We aimed to construct a competing risk model to predict the prognosis for older patients with TGCT.

Methods

We collected TGCT patients aged 50 years or older diagnosed between 2004 and 2015 from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database. We estimated the cumulative incidences of cause-specific death (CSD) and other causes of death and established a nomogram predicting cause-specific mortality in older patients with TGCT by Fine-Gray competing risk regression. The concordance index (C-index), calibration curves, area under the receiver operating characteristic curve (AUC), and decision analysis curves (DCA) were used to evaluate the differentiation, accuracy, and clinical significance of the nomogram.

Results

A total of 2,751 older TGCT patients were included in the study. The 3-, 5-, and 10-year cumulative incidences were 4.4, 5.0 and 6.1%, respectively, for cause-specific death, and 3.8, 6.2, 13.1%, respectively, for other causes of death. Predictors of cause-specific mortality in older TGCT included age, marital status, annual household income, histology, tumor size, stage and surgery. In the training and validation sets, the C-indexes were greater than 0.8, indicating that the nomogram had good discrimination. The AUC revealed the same result. The calibration curves showed good agreement between the predicted and observed results of the nomogram. DCA curves indicated that the nomogram had more clinical significance than the conventional American Joint Committee on Cancer (AJCC) staging. Based on the total nomogram score of each case, all patients were categorized into low-risk and high-risk groups, and risk categorization allowed the identification of cases with a high risk of death.

Conclusion

We established a competing risk nomogram with good performance that may help clinicians accurately predict the prognosis of older TGCT patients.

The Immune Landscape and Immunotherapeutic Strategies in Platinum-Refractory Testicular Germ Cell Tumors

Testicular germ cell tumors (TGCTs) are cancers with very good prognosis, even in the metastatic setting, with high curative potential mainly attributed to the introduction of cisplatin-based chemotherapy. However, approximately 15% of the patients develop platinum-refractory disease and suffer multiple relapses. Therefore, there is an unmet need for novel therapeutic agents with improved efficacy and minimal long-term side effects. Recent advances in the development of immunotherapeutic agents, particularly immune checkpoint inhibitors (ICIs), have offered an opportunity to test their activity in various tumor types, including GCTs. This review aims to analyze the immune microenvironment of these tumors and present the most recently available data from studies that have tested immunotherapeutic agents against GCTs. The majority of the available knowledge derives from case reports or small cohort studies, particularly those involving ICIs of the PD-1/PD-L1 axis alone or in combination with anti-CTLA-4 monoclonal antibodies. Other immunotherapeutic targeted approaches, including antibody-drug conjugates, antibody prodrugs, vaccines, tyrosine kinase inhibitors, chimeric antigen receptor (CAR) T-cell therapy, have biological rationales and have shown preliminary activity or are currently being tested. Growing evidence on these and other approaches will assist in broadening the currently limited treatment armamentarium against platinum-refractory TGCTs.

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

Background

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

Methods

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

Results

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

Conclusion

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

The fate of germ cells in cryptorchid testis

Cryptorchidism in males constitutes a notable risk factor for both infertility and testicular cancer. Infertility in adulthood is closely linked to the germ cell status in childhood. Furthermore, the significance of germ cell status is important as more than 95% of all reported testicular malignancies are germ cell tumors. The review aims to elucidate the pathogenesis of germ cells in cryptorchid testes concerning their association with infertility and testicular malignancies. Impaired germ cell numbers are evident in cryptorchid testes even during antenatal and neonatal stages. In cryptorchidism there is a rapid decline in germ cell number within the first year of life, partially attributed to physiologic gonocyte apoptosis. Additionally, germ cells fail to differentiate normally during mini-puberty leading to reduced germ cell proliferation and delayed clearance of gonocytes from the seminiferous epithelium. Absence of germ cells in testicular biopsies occurs already 10 months of age and germ cell deterioration progressively worsens with approximately 50% of persisting cryptorchid testes lacking germ cells during puberty. The deficient germ cell maturation and proliferation leads to later infertility. Elevated temperature in the cryptorchid testes and also hormonal deficiency contribute to this phenomenon. Germ cell neoplasia in situ (GCNIS) originating during fetal development may manifest in rare cases associated with disorders of sexual development, chromosomal abnormalities in boys, specific syndromes, and teratomas that include cryptorchidism. In adults, the presence of GCNIS predominantly represents a new histology pattern before invasive germ cell cancer is demonstrated and is neither congenital nor related to abnormal gonocyte transformation.

The burden of testicular cancer from 1990 to 2019 in the Middle East and North Africa region

Background

The incidence rate of testicular cancer has risen in many countries during recent decades. This study aimed to outline the impact of testicular cancer on the Middle East and North Africa (MENA) region from 1990 to 2019, examining its burden by age group and according to the socio-demographic index (SDI).

Methods

Data on the incidence, death, and disability-adjusted life-years (DALYs) due to testicular cancer were retrieved from the Global Burden of Disease study 2019. The counts and age-standardized rates (per 100,000) were reported, and all rates were accompanied by 95% uncertainty intervals (UIs).

Results

In MENA, the age-standardized incidence rate of testicular cancer was 1.4 per 100,000 in 2019, showing a 244.0% increase since 1990. Similarly, the annual death rate, at 0.1, experienced a 2.6% rise during the same period. In 2019, testicular cancer accounted for 31.1 thousand DALYs, marking an age-standardized rate of 5.0, which was 2.8% higher than in 1990. The 1-4 age group exhibited the largest incidence rate in 2019. In addition, in both 1990 and 2019 the MENA/Global DALY ratio was higher than one in the 1-14 year age groups. During the period 1990 to 2019, the age-standardized DALY rate of testicular cancer steadily rose with higher SDI values, except for a decrease observed at an SDI of 0.8.

Conclusion

Over the last thirty years, there has been a notable rise in the burden of testicular cancer in the MENA region.

Multiparametric Ultrasound for Diagnosing Testicular Lesions: Everything You Need to Know in Daily Clinical Practice

BACKGROUND

Ultrasonography (US) represents the gold standard imaging method for the assessment of testicular lesions (TL). The gray-scale (GSUS) and color-Doppler (CDUS) ultrasound examination allow sonographers to investigate the size, margins, echotexture, and vascular features of TLs with the aim to differentiate benign from malignant lesions. Recently, the use of contrast-enhanced US (CEUS) and sonoelastography (SE) has led to further improvements in the differential diagnosis of TL. Although GSUS and CDUS are often sufficient to suggest the benign or malignant nature of the TL, CEUS can be decisive in the differential diagnosis of unclear findings, while SE can help to strengthen the diagnosis. The contemporary combination of GSUS, CDUS, CEUS, and SE has led to a new diagnostic paradigm named multiparametric US (mp-US), which is able to provide a more detailed characterization of TLs than single techniques alone. This narrative and pictorial review aimed to describe the mp-US appearance of several TLs.

METHODS

An extensive Medline search was performed to identify studies in the English language focusing on the mp-US evaluation of TLs.

RESULTS

A practical mp-US "identity card" and iconographic characterization of several benign and malignant TLs is provided herein.

CONCLUSIONS

The mp-US characterization of TL reported herein can be useful in daily clinical practice.

Seminoma and dysgerminoma: evidence for alignment of clinical trials and de-escalation of systemic chemotherapy

Malignant germ cell tumours are a group of rare cancers whose incidence peaks in late adolescence and early adulthood. Dysgerminomas of the ovary and seminomas of the testis are analogous diseases, but seminomas have a 10-fold higher incidence. The two tumours are morphologically identical and are only differentiated by surrounding organ-specific tissue or testicular germ cell neoplasia in situ. They share genetic features including KIT and RAS mutations, amplification of chromosome 12p, and expression of pluripotency markers (NANOG (Nanog homeobox), OCT3/4 (Octamer-binding transcription factor 3/4), and SAL4 (Spalt-like trascription factor 4)). Both histologies are exquisitely sensitive to platinum chemotherapy, and the combination of bleomycin, etoposide, and cisplatin (BEP) yields survival rates greater than 90%. However, BEP causes significant, lifelong toxicity (cardiovascular, renal, respiratory, and neurological) in these young patients with an expectation of cure. Here, we comprehensively review the biological features of dysgerminoma and seminoma to demonstrate that they are biologically analogous diseases. We present available clinical trial data supporting de-escalation of chemotherapy treatment. Finally, we propose that future trials should enrol men, women, and children to benefit all patients regardless of age or sex.

Cytological spectrum of testicular malignancies with histopathological correlation: A retrospective analysis

BACKGROUND

Testicular malignancy is the most common solid organ cancer occurring in young men. The most common testicular malignancy is germ cell tumor. Extragonadal malignancies such as lymphomas are rare. Testicular fine-needle aspiration cytology (FNAC) in cancer is a bit controversial amidst fear of tumor seeding along the needle tract. Nevertheless, its largely safe, cost-effective technique providing a quick and fairly reliable diagnosis.

METHODS

A retrospective analysis of testicular malignancies on FNAC over a period of 9 years with cyto-histological correlation wherever possible was carried out. FNAC slides and cell blocks with immunocytochemistry wherever done were retrieved.

RESULTS

A total of 74 cases were obtained. The age ranged from 1 year to 65 years. Infiltration by leukemia was the most common malignancy detected in pediatric population, while germ cell tumors were common amongst young adults and middle-aged men. In elderly, metastatic carcinoma, infiltration by lymphoma were identified. On FNAC, 38 cases were of leukemic infiltration, 27 of germ cell tumors (subtyped as mixed germ cell tumors-15 cases, seminoma-11 cases, and yolk sac tumor-1 case) with two cases each of non-Hodgkin lymphoma, Leydig cell tumor, metastatic adenocarcinoma, and one case each of metastatic small cell carcinoma, rhabdomyosarcoma, and malignant neoplasm. Histological correlation was available in 15/74 cases. Only 3 cases were discordant. Seeding of tumor along the needle tract was not seen.

CONCLUSION

The current study deciphers the cytological spectrum of testicular malignancies on FNAC and highlights its importance as a reliable modality for a prompt diagnosis of testicular tumors guiding patient management.

Metastatic Testicular Cancer Patterns and Predictors: A Contemporary Population-based SEER Analysis

OBJECTIVE

To elucidate clinical and demographic predictors of metastatic testicular cancer (TC) at presentation and study the impact of these factors on prognosis. Patients with metastatic TC experience poorer outcomes than those with localized or locoregional disease. Social determinants of health may compound this trend.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried to identify 16,528 patients aged ≥18 with TC diagnosed from 2010 to 2016. Descriptive statistics were analyzed using Fisher exact test and Pearson chi-square test for continuous and categorical variables. Predictors of specific metastases and factors impacting cancer-specific mortality (CSM) were evaluated using multivariate logistic regression analysis and competing risks regression, respectively.

RESULTS

Of 16,474 patients with complete data, 1877 (11.39%) had distant metastases at diagnosis. These patients more commonly featured disease-specific and demographic variables associated with worse health outcomes (all P < .001). Lung metastases were the predominant site of synchronous and solitary metastases. Disease-specific predictors of metastasis included T stage, histology, tumor size, lymphovascular invasion, and cryptorchidism. Patient-specific predictors included age, geography, ethnicity, race, marital status, and socioeconomic status. Nearly one-fourth of patients with metastases died. Poor CSM was predicted by histology, age, insurance status, and socioeconomic status. All metastatic sites except bone were associated with worse CSM, with lung metastases conferring the greatest risk.

CONCLUSION

This cross-sectional study identifies variables associated with TC metastasis and survival, particularly highlighting the importance of social determinants of health in TC mortality. These findings can facilitate a risk-stratified approach to staging and management while supporting new approaches to target disparities.

Subsets of preoperative sex hormones in testicular germ cell cancer: a retrospective multicenter study

Preoperative homeostasis of sex hormones in testicular germ cell tumor (TGCT) patients is scarcely characterized. We aimed to explore regulation of sex hormones and their implications for histopathological parameters and prognosis in TGCT using a data-driven explorative approach. Pre-surgery serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), estradiol (E2) and prolactin were measured in a retrospective multicenter TGCT cohort (n = 518). Clusters of patients were defined by latent class analysis. Clinical, pathologic and survival parameters were compared between the clusters by statistical hypothesis testing, Random Forest modeling and Peto-Peto test. Cancer tissue expression of sex hormone-related genes was explored in the publicly available TCGA cohort (n = 149). We included 354 patients with pure seminoma and 164 patients with non-seminomatous germ cell tumors (NSGCT), with a median age of 36 years. Three hormonal clusters were defined: 'neutral' (n = 228) with normal sex hormone homeostasis, 'testicle' (n = 91) with elevated T and E2, low pituitary hormones, and finally 'pituitary' subset (n = 103) with increased FSH and LH paralleled by low-to-normal levels of the gonadal hormones. Relapse-free survival in the hormonal subsets was comparable (p = 0.64). Cancer tissue expression of luteinizing hormone- and follicle-stimulating hormone-coding genes was significantly higher in seminomas, while genes of T and E2 biosynthesis enzymes were strongly upregulated in NSGCT. Substantial percentages of TGCT patients are at increased risk of sex hormone dysfunction at primary diagnosis before orchiectomy. TGCT may directly influence systemic hormonal homeostasis by in-situ synthesis of sex hormones.

Development and validation of a nomogram to predict lung metastasis in patients with testicular germ cell tumors

Background

Lung metastatic tumor (LM) is one of testicular germ cell tumors' most common metastatic sites. Our study aimed to develop a nomogram for predicting the risk of LM among patients with testicular germ cell tumors (TGCTs).

Methods

Clinicopathological information of 4078 patients with TGCT between 2010 and 2015 was obtained from SEER. Univariate and multivariate logistic regression analyses were performed to identify risk factors for LM, and a nomogram was developed based on these factors. Calibration curves, area under the receiver operating curve (AUC), and decision curve analysis (DCA) were used to evaluate the accuracy and discrimination of the model.

Results

Study participants included 4078 people with TGCTs, including 305 people with LM. They were randomly divided into two groups (training cohort = 2854 and validation cohort = 1224) at a ratio of 7:3. The following variables were incorporated in the nomogram: marital status, tumor histological type, T stage, brain metastasis, liver metastasis, lactate dehydrogenase (LDH), and chemotherapy. Besides, the AUC of it was 0.922 in the training cohort, while was 0.930 in the validation cohort. Training and validation cohort calibrations showed that the nomogram had excellent predictive abilities. DCA suggested it was more clinically relevant than the traditional TN staging.

Conclusion

We have established a nomogram to predict the risk of LM in patients with TGCTs. Doctors and patients can use this nomogram to monitor and identify lung metastasis of tumors through active monitoring and follow-up.

miRNAs orchestration of testicular germ cell tumors - Particular emphasis on diagnosis, progression and drug resistance

Testicular cancer (TC) is one of the most frequently incident solid tumors in males. A growing prevalence has been documented in developed countries. Although recent advances have made TC an exceedingly treatable cancer, numerous zones in TC care still have divisive treatment decisions. In addition to physical examination and imaging techniques, conventional serum tumor markers have been traditionally used for the diagnosis of testicular germ cell tumors (TGCT). Unlike other genital and urinary tract tumors, recent research methods have not been broadly used in TGCTs. Even though several challenges in TC care must be addressed, a dedicated group of biomarkers could be particularly beneficial to help classify patient risk, detect relapse early, guide surgery decisions, and tailor follow-up. Existing tumor markers (Alpha-fetoprotein, human chorionic gonadotrophin, and lactate dehydrogenase) have limited accuracy and sensitivity when used as diagnostic, prognostic, or predictive markers. At present, microRNAs (miRNA or miR) play a crucial role in the process of several malignancies. The miRNAs exhibit pronounced potential as novel biomarkers since they reveal high stability in body fluids, are easily detected, and are relatively inexpensive in quantitative assays. In this review, we aimed to shed light on the recent novelties in developing microRNAs as diagnostic and prognostic markers in TC and discuss their clinical applications in TC management.

Sonoelastography for Testicular Tumor Identification: A Systematic Review and Meta-Analysis of Diagnostic Test Accuracy

The objective of this review was to summarize the applications of sonoelastography in testicular tumor identification and inquire about their test performances. Two authors independently searched English journal articles and full conference papers from CINAHL, Embase, IEEE Xplore®, PubMed, Scopus, and Web of Science from inception and organized them into a PIRO (patient, index test, reference test, outcome) framework. Eleven studies (n = 11) were eligible for data synthesis, nine of which (n = 9) utilized strain elastography and two (n = 2) employed shear-wave elastography. Meta-analyses were performed on the distinction between neoplasm (tumor) and non-neoplasm (non-tumor) from four study arms and between malignancy and benignity from seven study arms. The pooled sensitivity of classifying malignancy and benignity was 86.0% (95%CI, 79.7% to 90.6%). There was substantial heterogeneity in the classification of neoplasm and non-neoplasm and in the specificity of classifying malignancy and benignity, which could not be addressed by the subgroup analysis of sonoelastography techniques. Heterogeneity might be associated with the high risk of bias and applicability concern, including a wide spectrum of testicular pathologies and verification bias in the reference tests. Key technical obstacles in the index test were manual compression in strain elastography, qualitative observation of non-standardized color codes, and locating the Regions of Interest (ROI), in addition to decisions in feature extractions. Future research may focus on multiparametric sonoelastography using deep learning models and ensemble learning. A decision model on the benefits-risks of surgical exploration (reference test) could also be developed to direct the test-and-treat strategy for testicular tumors.

Cannabis- and Substance-Related Carcinogenesis in Europe: A Lagged Causal Inferential Panel Regression Study

Recent European data facilitate an epidemiological investigation of the controversial cannabis-cancer relationship. Of particular concern were prior findings associating high-dose cannabis use with reproductive problems and potential genetic impacts. Cancer incidence data age-standardised to the world population was obtained from the European Cancer Information System 2000-2020 and many European national cancer registries. Drug use data were obtained from the European Monitoring Centre for Drugs and Drug Addiction. Alcohol and tobacco consumption was sourced from the WHO. Median household income was taken from the World bank. Cancer rates in high-cannabis-use countries were significantly higher than elsewhere (β-estimate = 0.4165, p = 3.54 × 10^-115). Eighteen of forty-one cancers (42,675 individual rates) were significantly associated with cannabis exposure at bivariate analysis. Twenty-five cancers were linked in inverse-probability-weighted multivariate models. Temporal lagging in panel models intensified these effects. In multivariable models, cannabis was a more powerful correlate of cancer incidence than tobacco or alcohol. Reproductive toxicity was evidenced by the involvement of testis, ovary, prostate and breast cancers and because some of the myeloid and lymphoid leukaemias implicated occur in childhood, indicating inherited intergenerational genotoxicity. Cannabis is a more important carcinogen than tobacco and alcohol and fulfills epidemiological qualitative and quantitative criteria for causality for 25/41 cancers. Reproductive and transgenerational effects are prominent. These findings confirm the clinical and epidemiological salience of cannabis as a major multigenerational community carcinogen.

Testicular germ cell tumour risk by occupation and industry: a French case-control study - TESTIS

OBJECTIVE

Testicular germ cell tumours (TGCT) are the most common cancer in men of working age and its incidence has increased notably over the past 40 years. Several occupations have been identified as potentially associated with TGCT risk. The aim of this study was to further explore the relationship between occupations, industries and TGCT risk in men aged 18-45 years.

METHODS

The TESTIS study is a multicenter case-control study conducted between January 2015 and April 2018 in 20 of 23 university hospital centers in metropolitan France. A total of 454 TGCT cases and 670 controls were included. Full job histories were collected. Occupations were coded according to the International Standard Classification of Occupation 1968 version (ISCO-1968) and industry according to the 1999 version of Nomenclature d'Activités Française (NAF-1999). For each job held, ORs and 95% CIs were estimated using conditional logistic regression.

RESULTS

A positive association was observed between TGCT and occupation as agricultural, animal husbandry worker (ISCO: 6-2; OR 1.71; 95% CI (1.02 to 2.82)), as well as salesman (ISCO: 4-51; OR 1.84; 95% CI (1.20 to 2.82)). An increased risk was further observed among electrical fitters and related, electrical and electronics workers employed for 2 years or more (ISCO: 8-5; OR≥2 years 1.83; 95% CI (1.01 to 3.32)). Analyses by industry supported these findings.

CONCLUSIONS

Our findings suggest that agricultural, electrical and electronics workers, and salesmen workers experience an increased risk of TGCT. Further research is needed to identify the agents or chemicals in these high-risk occupations which are relevant in the TGCT development.

TRIAL REGISTRATION NUMBER

NCT02109926.

Development and validation of a nomogram for predicting the overall survival of patients with testicular cancer

BACKGROUND

The purpose of this study was to develop and validate a nomogram to predict survival in testicular cancer patients.

METHODS

Testicular cancer patients diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database were selected for this study. A random sampling method was used to divide patients into training and validation cohorts, which accounted for 30% and 70% of the total sample, respectively. The nomogram was developed using the training cohort and evaluated using the C index, calibration chart, and area under the receiver operating characteristic curve (AUC).

RESULTS

Seven risk factors that affect the survival of testicular cancer patients (AJCC stage, marital status, age at diagnosis, race, SEER historic stage A, surgery status, and origin) were identified using Cox proportional hazard regression analysis. The nomogram has a higher C index (0.897) and AUC when compared with the AJCC staging system. The results of the calibration chart of the nomogram show that the predicted survival of testicular cancer patients at 3, 5, and 10 years after diagnosis is very close to their actual survival.

CONCLUSIONS

We developed and validated a nomogram for predicting the survival rate of testicular cancer patients at 3, 5, and 10 years after diagnosis. This nomogram has better discrimination, calibration, and clinical validity than the AJCC staging system. This indicates that the nomogram can be used to predict the survival of testicular cancer patients effectively, and provide a reference for patient treatment strategies.

Effect of 12-months testosterone replacement therapy on bone mineral density and markers of bone turnover in testicular cancer survivors - results from a randomized double-blind trial

BACKGROUND

Testicular cancer survivors (TCS) are at risk of Leydig cell insufficiency, which is a condition characterized by elevated luteinising hormone (LH) in combination with low levels of testosterone. It has been suggested that this condition is associated with impaired metabolic profile and low bone mineral density (BMD). The primary aim of the randomized double-blind trial NCT02991209 was to evaluate metabolic profile after 12-months testosterone replacement therapy (TRT) in TCS with mild Leydig cell insufficiency. Here we present the secondary outcomes of changes in BMD and markers of bone turnover.

METHODOLOGY

In total, 69 TCS with mild Leydig cell insufficiency were randomized 1:1 to 12 months TRT (n = 35) (Tostran, gel, 2%, applied transdermally, with a maximum daily dose of 40 mg) or placebo (n = 34). BMD and markers of bone turnover were evaluated at baseline, after 6- and 12-months TRT, and 3-months post-treatment. Linear mixed effects models were used to analyse changes in BMD, N-terminal propeptide of type 1 procollagen (P1NP) and C-terminal telopeptide of type I collagen (CTX).

RESULTS

After 12 months treatment, TRT was not associated with a statistically significant difference in BMD compared to placebo; total body BMD: 0.01 g/cm2 (95% confidence interval (CI): -0.01 - 0.02), BMD of the lumbar spine: 0.01 g/cm2, (95% CI: -0.01-0.03), BMD of the left femoral neck: 0.00, (95% CI: -0.01-0.02). TRT was associated with a small but statistically significant increase in P1NP: 11.65 µg/L (95% CI: 3.96, 19.35), while there was no difference in CTX.

CONCLUSION

12 months of TRT did not change BMD, while there was as small and clinically irrelevant increase in P1NP compared to placebo in TCS with mild Leydig cell insufficiency. The findings need validation in a larger cohort.

Genome-scale CRISPR screen reveals neddylation to contribute to cisplatin resistance of testicular germ cell tumours

BACKGROUND

Type II testicular germ cell tumours (TGCT) are the most prevalent tumours in young men. Patients suffering from cisplatin-resistant TGCTs are facing very poor prognosis demanding novel therapeutic options. Neddylation is a known posttranslational modification mediating many important biological processes, including tumorigenesis. Overactivation of the neddylation pathway promotes carcinogenesis and tumour progression in various entities by inducing proteasomal degradation of tumour suppressors (e.g., p21, p27).

METHODS

We used a genome-scale CRISPR/Cas9 activation screen to identify cisplatin resistance factors. TGCT cell lines were treated with the neddylation inhibitor (MLN4924)/cisplatin/combination and investigated for changes in viability (XTT assay), apoptosis/cell cycle (flow cytometry) as well as in the transcriptome (3'mRNA sequencing).

RESULTS

NAE1 overexpression was detected in cisplatin-resistant colonies from the CRISPR screen. Inhibition of neddylation using MLN4924 increased cisplatin cytotoxicity in TGCT cell lines and sensitised cisplatin-resistant cells towards cisplatin. Apoptosis, G2/M-phase cell cycle arrest, γH2A.X/P27 accumulation and mesoderm/endoderm differentiation were observed in TGCT cells, while fibroblast cells were unaffected.

CONCLUSIONS

We identified overactivation of neddylation as a factor for cisplatin resistance in TGCTs and highlighted the additive effect of NAE1 inhibition by MLN4924 in combination with cisplatin as a novel treatment option for TGCTs.

Risk and mortality of testicular cancer in patients with neurodevelopmental or other psychiatric disorders

BACKGROUND

Both testicular germ cell tumours (TGCT) and neurodevelopmental disorders are associated with urogenital malformations. Few studies have investigated the association between psychiatric disorders and TGCT. We investigated whether history of any psychiatric or neurodevelopmental disorder is associated with increased risk or mortality of TGCT.

METHOD

This is a nested case-control study including 6166 TGCT patients diagnosed during 1992-2014, individually matched for age and calendar period to 61,660 controls. We calculated odds ratios (ORs) for the association between type of psychiatric diagnoses and TGCT risk. Among the cases, we used a cohort design and calculated hazard ratios (HRs) of the association between psychiatric diagnose and all-cause and TGCT-specific death.

RESULTS

History of a neurodevelopmental disorder (attention deficit hyperactivity disorder, autism spectrum disorder and intellectual disabilities) was associated with an increased risk of seminoma (OR: 1.54; 1.09-2.19). Seminoma patients with neurodevelopmental disorders were younger (34 versus 38 years, p = 0.004) and had more stage IV disease (5.4% versus 1.2%) than those without. Psychiatric history overall was not associated with TGCT. Patient history of any psychiatric disorder was associated with an increased all-cause and TGCT-specific death.

CONCLUSIONS

We report an association between neurodevelopmental disorders and testicular seminoma, and an increased TGCT-specific mortality for TGCT patients with psychiatric disorders.

No evidence for seasonal variations of the incidence of testicular germ cell tumours in Germany

The pathogenesis of testicular germ cell tumours (GCTs) is still incompletely understood. Any progress in its understanding must derive from observational studies. Recently, it has been suggested that the incidence of GCTs may follow a seasonal pattern based on circannual changes in the Vitamin D serum levels, with maximum incidence rates in winter months. To examine this promising hypothesis, we studied monthly incidence rates of testicular GCTs in Germany by analysing 30,988 GCT cases aged 15-69 years, diagnosed during 2009-2019. Monthly incident case numbers with data regarding histology and patient age were obtained from the Robert Koch Institut, Berlin, along with annual male population counts. We used precision weighting for deriving pooled monthly incidence rates for GCTs of the period 2009-2019. We stratified pooled rates by histology (seminoma and nonseminoma) and age (15-39 and 40-69 years). By assuming a cyclical effect, we used an estimator of the intensity of seasonal occurrence and report seasonal relative risks (RR). The mean monthly incidence rate was 11.93/105 person-months. The seasonal RR for testicular cancer over-all is 1.022 (95% CI 1.000-1.054). The highest seasonal RR was found in the subgroup of nonseminoma aged 15-39 years, with a RR 1.044 (95% CI 1.000-1.112). The comparison of the pooled monthly rates of the winter months (October-March) with the summer months (April-September) revealed a maximum relative difference of 5% (95% CI 1-10%) for nonseminoma, aged 15-39 years. We conclude that there is no evidence of a seasonal variation of incidence rates of testicular cancer. Our results are at odds with an Austrian study, but the present data appear sound because the results were obtained with precision weighted monthly incidence rates in a large population of GCT cases.

Breaking the Mold: Epigenetics and Genomics Approaches Addressing Novel Treatments and Chemoresponse in TGCT Patients

Testicular germ-cell tumors (TGCT) have been widely recognized for their outstanding survival rates, commonly attributed to their high sensitivity to cisplatin-based therapies. Despite this, a subset of patients develops cisplatin resistance, for whom additional therapeutic options are unsuccessful, and ~20% of them will die from disease progression at an early age. Several efforts have been made trying to find the molecular bases of cisplatin resistance. However, this phenomenon is still not fully understood, which has limited the development of efficient biomarkers and precision medicine approaches as an alternative that could improve the clinical outcomes of these patients. With the aim of providing an integrative landscape, we review the most recent genomic and epigenomic features attributed to chemoresponse in TGCT patients, highlighting how we can seek to combat cisplatin resistance through the same mechanisms by which TGCTs are particularly hypersensitive to therapy. In this regard, we explore ongoing treatment directions for resistant TGCT and novel targets to guide future clinical trials. Through our exploration of recent findings, we conclude that epidrugs are promising treatments that could help to restore cisplatin sensitivity in resistant tumors, shedding light on potential avenues for better prognosis for the benefit of the patients.

Treatment de-escalation for stage II seminoma

International Germ Cell Cancer Collaborative Group good-risk metastatic seminoma has cure rates of >95%. Within this risk group, patients with stage II disease exhibit the best oncological outcomes with the standard-of-care treatment strategies of radiotherapy or combination chemotherapy. However, these treatments can be associated with substantial early and late toxic effects. Therapy de-escalation aims to reduce treatment morbidity whilst preserving oncological outcomes. The evidence supporting such approaches is largely from non-randomized institutional data, and therefore this strategy is not recognized as standard of care. Current de-escalation approaches for stage II seminoma include single-agent chemotherapy, radiotherapy and surgery based on early data from clinical studies. Increased recognition of emerging data on treatment modification to reduce morbidity whilst maintaining cure rates and consideration of therapy de-escalation could improve patient survivorship outcomes.

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

Background

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

Methods

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

Results

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

Conclusions

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

Clinical features and prognostic factors in patients diagnosed with lymphovascular invasion of testicular germ-cell tumors: Analysis based on the SEER database

Background

Lymphovascular invasion (LVI) is a high-risk factor for testicular germ-cell tumors (TGCT), but a prognostic model for TGCT-LVI patients is lacking. This study aimed to develop a nomogram for predicting the overall survival (OS) of TGCT-LVI patients.

Methods

A complete cohort of 3288 eligible TGCG-LVI patients (training cohort, 2300 cases; validation cohort, 988 cases) were obtained from the Surveillance, Epidemiology, and End Results database. Variables screened by multivariate Cox regression analysis were used to construct a nomogram, which was subsequently evaluated using the consistency index (C-index), time-dependent receiver operating characteristic curve (ROC), and calibration plots. The advantages and disadvantages of the American Joint Committee on Cancer (AJCC) staging system and the nomogram were assessed by integrated discrimination improvement (IDI) and net reclassification improvement (NRI). Decision-analysis curve (DCA) was used to measure the net clinical benefit of the nomogram versus the AJCC staging system. Finally, Kaplan-Meier curves were used to evaluate the ability to identify different risk groups between the traditional AJCC staging system and the new risk-stratification system built on the nomogram.

Results

Nine variables were screened by multivariate Cox regression analysis to construct the nomogram. The C-index (training cohort, 0.821; validation cohort, 0.819) and time-dependent ROC of 3-, 5-, and 9-year OS between the two cohorts suggested that the nomogram had good discriminatory ability. Calibration curves showed good consistency of the nomogram. The NRI values of 3-, 5-, and 9-year OS were 0.308, 0.274, and 0.295, respectively, and the corresponding values for the validation cohort were 0.093, 0.093, and 0.099, respectively (P<0.01). Additionally, the nomogram had more net clinical benefit as shown by the DCA curves, and the new risk-stratification system provided better differentiation than the AJCC staging system.

Conclusions

A prognostic nomogram and new risk-stratification system were developed and validated to assist clinicians in assessing TGCT-LVI patients.

Advancing clinical and translational research in germ cell tumours (GCT): recommendations from the Malignant Germ Cell International Consortium

Germ cell tumours (GCTs) are a heterogeneous group of rare neoplasms that present in different anatomical sites and across a wide spectrum of patient ages from birth through to adulthood. Once these strata are applied, cohort numbers become modest, hindering inferences regarding management and therapeutic advances. Moreover, patients with GCTs are treated by different medical professionals including paediatric oncologists, neuro-oncologists, medical oncologists, neurosurgeons, gynaecological oncologists, surgeons, and urologists. Silos of care have thus formed, further hampering knowledge dissemination between specialists. Dedicated biobank specimen collection is therefore critical to foster continuous growth in our understanding of similarities and differences by age, gender, and site, particularly for rare cancers such as GCTs. Here, the Malignant Germ Cell International Consortium provides a framework to create a sustainable, global research infrastructure that facilitates acquisition of tissue and liquid biopsies together with matched clinical data sets that reflect the diversity of GCTs. Such an effort would create an invaluable repository of clinical and biological data which can underpin international collaborations that span professional boundaries, translate into clinical practice, and ultimately impact patient outcomes.

Paternal Occupational Exposure to Heavy Metals and Welding Fumes and Testicular Germ Cell Tumours in Sons in France

Testicular cancer is the most common cancer in young men. Its causes are largely unknown, although prenatal occupational and environmental exposures have been suggested. We investigated paternal occupational exposure to heavy metals and welding fumes and the risk of testicular germ cell tumors (TGCT) in their offspring. A total of 454 cases and 670 controls were included from a French nationwide case-control study. The INTEROCC job exposure matrix was used to assign occupational exposures (cadmium, chromium, iron, nickel, lead, and welding fumes) to the fathers' jobs. Odds ratios (ORs) for TGCT were estimated using conditional logistic regression models for frequency-matched sets. Three complementary analytical approaches were used: (1) single-agent analysis, (2) analysis by groups, and (3) principal component analysis (PCA). The proportion of paternal exposure to different heavy metals and welding fumes ranged from 0.7% (cadmium) to 11.3% (lead). Based on PCA, three principal components explained 93.5% of the cumulative variance. No associations were found between heavy metals or welding fumes and TGCT. In this study, paternal occupational exposure to heavy metals or welding fumes was not associated with TGCT development in their sons.

State Trends of Cannabis Liberalization as a Causal Driver of Increasing Testicular Cancer Rates across the USA

BACKGROUND

The cause of the worldwide doubling-tripling of testicular cancer rates (TCRs) in recent decades is unknown. Previous cohort studies associated cannabis use with TCR including dose-response relationships but the contribution of cannabis to TCRs at the population level is unknown. This relationship was tested by analyzing annual trends across US states and formally assessed causality. Four US datasets were linked at state level: age-adjusted TCRs from Centers for Disease Control Surveillance Epidemiology and End Results database; drug use data from annual National Survey of Drug Use and Health including 74.1% response rate; ethnicity and median household income data from the US Census Bureau; and cannabinoid concentration data from Drug Enforcement Agency reports. Data was processed in R in spatiotemporal and causal inference protocols.

RESULTS

Cannabis-use quintile scatterplot-time and boxplots closely paralleled those for TCRs. The highest cannabis-use quintile had a higher TCR than others (3.44 ± 0.05 vs. 2.91 ± 0.2, mean ± S.E.M., t = 10.68, p = 1.29 × 10-22). A dose-response relationship was seen between TCR and Δ9-tetrahydrocannabinol (THC), cannabinol, cannabigerol, and cannabichromene (6.75 × 10-9 < p < 1.83 × 10-142). In a multivariate inverse probability-weighted interactive regression including race and ethnic cannabis exposure (ECE), ECE was significantly related to TCR (β-estimate = 0.89 (95%C.I. 0.36, 2.67), p < 2.2 × 10-16). In an additive geospatiotemporal model controlling for other drugs, cannabis alone was significant (β-estimate = 0.19 (0.10, 0.28), p = 3.4 × 10-5). In a full geospatial model including drugs, income and ethnicity cannabinoid exposure was significant (cannabigerol: β-estimate = 1.39 (0.024, 2.53), p = 0.0017); a pattern repeated at two spatial and two temporal lags (cannabigerol: β-estimate = 0.71 (0.05, 1.37), p = 0.0.0350; THC: β-estimate = 23.60 (11.92, 35.29), p = 7.5 × 10-5). 40/41 e-Values > 1.25 ranged up to 1.4 × 1063 and 10 > 1000 fitting causal relationship criteria. Cannabis liberalization was associated with higher TCRs (ChiSqu. = 312.2, p = 2.64 × 10-11). Rates of TC in cannabis-legal states were elevated (3.36 ± 0.09 vs. 3.01 ± 0.03, t = 4.69, p = 4.86 × 10-5).

CONCLUSIONS

Cannabis use is closely and causally associated with TCRs across both time and space and higher in States with liberal cannabis legislation. Strong dose-response effects were demonstrated for THC, cannabigerol, cannabinol, cannabichromene and cannabidiol. Cannabinoid genotoxicity replicates all major steps to testicular carcinogenesis including whole-genome doubling, chromosomal arm excision, generalized DNA demethylation and chromosomal translocations thereby accelerating the pathway to testicular carcinogenesis by several decades.

Different Expression Patterns of Metabolic Reprogramming Proteins in Testicular Germ Cell Cancer

Metabolic reprogramming is an emerging hallmark of cancer, involving the overexpression of metabolism-related proteins, such as glucose and monocarboxylate transporters and intracellular glycolytic enzymes. The biology of testicular germ cell tumors (TGCTs) is very complex, and although their metabolic profile has been scantily explored, some authors have recently reported that the metabolic rewiring of cancer cells resulted in an association with aggressive clinicopathological characteristics. In this study we have investigated, by immunohistochemical analysis, the expression of key proteins sustaining the hyperglycolytic phenotype in pure seminoma (SE, nr. 35), pure embryonal carcinoma (EC, nr. 17) tissues samples, and normal testes (nr. 5). GLUT1, CD44, PFK-1, MCT1, MCT4, LDH-A, and PDH resulted in more expression in EC cells compared to SE cells. TOM20 was more expressed in SE than in EC. GLUT1, MCT1, and MCT4 expression showed a statistically significant association with SE histology, while for EC, the association resulted in being significant only for GLUT1 and MCT4. Finally, we observed that EC resulted as negative for p53, suggesting that the GLUT1 and MTC overexpression observed in EC could be also attributed to p53 downregulation. In conclusion, our findings evidenced that EC exhibits a higher expression of markers of active aerobic glycolysis compared to SE, suggesting that the aggressive phenotype is associated with a higher glycolytic rate. These data corroborate the emerging evidence on the involvement of metabolic reprogramming in testicular malignancies as well, highlighting that the metabolic players should be explored in the future as promising therapeutic targets.

Association Study between Polymorphisms in DNA Methylation-Related Genes and Testicular Germ Cell Tumor Risk

BACKGROUND

Testicular germ cell tumors (TGCT), histologically classified as seminomas and nonseminomas, are believed to arise from primordial gonocytes, with the maturation process blocked when they are subjected to DNA methylation reprogramming. SNPs in DNA methylation machinery and folate-dependent one-carbon metabolism genes have been postulated to influence the proper establishment of DNA methylation.

METHODS

In this pathway-focused investigation, we evaluated the association between 273 selected tag SNPs from 28 DNA methylation-related genes and TGCT risk. We carried out association analysis at individual SNP and gene-based level using summary statistics from the Genome Wide Association Study meta-analysis recently conducted by the international Testicular Cancer Consortium on 10,156 TGCT cases and 179,683 controls.

RESULTS

In individual SNP analyses, seven SNPs, four mapping within MTHFR, were associated with TGCT risk after correction for multiple testing (q ≤ 0.05). Queries of public databases showed that three of these SNPs were associated with MTHFR changes in enzymatic activity (rs1801133) or expression level in testis tissue (rs12121543, rs1476413). Gene-based analyses revealed MTHFR (q = 8.4 × 10-4), methyl-CpG-binding protein 2 (MECP2; q = 2 × 10-3), and ZBTB4 (q = 0.03) as the top TGCT-associated genes. Stratifying by tumor histology, four MTHFR SNPs were associated with seminoma. In gene-based analysis MTHFR was associated with risk of seminoma (q = 2.8 × 10-4), but not with nonseminomatous tumors (q = 0.22).

CONCLUSIONS

Genetic variants within MTHFR, potentially having an impact on the DNA methylation pattern, are associated with TGCT risk.

IMPACT

This finding suggests that TGCT pathogenesis could be associated with the folate cycle status, and this relation could be partly due to hereditary factors.

Profiling the 3D interaction between germ cell tumors and microenvironmental cells at the transcriptome and secretome level

The tumor microenvironment (TM), consisting of the extracellular matrix (ECM), fibroblasts, endothelial cells, and immune cells, might affect tumor invasiveness and the outcome of standard chemotherapy. This study investigated the cross talk between germ cell tumors (GCT) and surrounding TM cells (macrophages, T-lymphocytes, endothelial cells, and fibroblasts) at the transcriptome and secretome level. Using high-throughput approaches of three-dimensional (3D) co-cultured cellular aggregates, this study offers newly identified pathways to be studied with regard to sensitivity toward cisplatin-based chemotherapy or tumor invasiveness as a consequence of the cross talk between tumor cells and TM components. Mass-spectrometry-based secretome analyses revealed that TM cells secreted factors involved in ECM organization, cell adhesion, angiogenesis, and regulation of insulin-like growth factor (IGF) transport. To evaluate direct cell-cell contacts, green fluorescent protein (GFP)-expressing GCT cells and mCherry-expressing TM cells were co-cultured in 3D. Afterward, cell populations were separated by flow cytometry and analyzed by RNA sequencing. Correlating the secretome with transcriptome data indicated molecular processes such as cell adhesion and components of the ECM being enriched in most cell populations. Re-analyses of secretome data with regard to lysine- and proline-hydroxylated peptides revealed a gain in proteins, such as collagens and fibronectin. Cultivation of GCT cells on collagen I/IV- or fibronectin-coated plates significantly elevated adhesive and migratory capacity, while decreasing cisplatin sensitivity of GCT cells. Correspondingly, cisplatin sensitivity was significantly reduced in GCT cells under the influence of conditioned medium from fibroblasts and endothelial cells. This study sheds light on the cross talk between GCT cells and their circumjacent TM, which results in deposition of the ECM and eventually promotes a pro-tumorigenic environment through enhanced migratory and adhesive capacity, as well as decreased cisplatin sensitivity. Hence, our observations indicate that targeting the ECM and its cellular components might be a novel therapeutic option in combination with cisplatin-based chemotherapy for GCT patients.

The Role of CT in the Staging and Follow-Up of Testicular Tumors: Baseline, Recurrence and Pitfalls

Ultrasound imaging of the testis represents the standard-of-care initial imaging for the diagnosis of TGCT, whereas computed tomography (CT) plays an integral role in the initial accurate disease staging (organ-confined, regional lymph nodes, or sites of distant metastases), in monitoring the response to therapy in patients who initially present with non-confined disease, in planning surgical approaches for residual masses, in conducting follow-up surveillance and in determining the extent of recurrence in patients who relapse after treatment completion. CT imaging has also an important place in diagnosing complications of treatments. The aims of this article are to review these different roles of CT in primary TGCT and focus on different pitfalls that radiologists need to be aware of.

RANKL regulates testicular cancer growth and Denosumab treatment has suppressive effects on GCNIS and advanced seminoma

BACKGROUND

Testicular germ cell tumours (TGCTs) have a high sensitivity to chemotherapy and a high cure rate, although with serious adverse effects. In the search for tumour suppressive drugs, the RANKL inhibitor Denosumab, used to treat osteoporosis, came up as a candidate since RANKL signalling was recently identified in the testis.

METHODS

Expression of RANKL, RANK and OPG, and the effects of RANKL inhibition were investigated in human TGCTs, TGCT-derived cell-lines, and TGCT-xenograft models. Serum RANKL was measured in TGCT-patients.

RESULTS

RANKL, RANK, and OPG were expressed in germ cell neoplasia in situ (GCNIS), TGCTs, and TGCT-derived cell lines. RANKL-inhibition reduced proliferation of seminoma-derived TCam-2 cells, but had no effect on embryonal carcinoma-derived NTera2 cells. Pretreatment with Denosumab did not augment the effect of cisplatin in vitro. However, inhibition of RANKL in vivo reduced tumour growth exclusively in the TCam-2-xenograft model and Denosumab-treatment decreased proliferation in human GCNIS cultures. In TGCT-patients serum RANKL had no prognostic value.

CONCLUSIONS

This study shows that the RANKL signalling system is expressed in GCNIS and seminoma where RANKL inhibition suppresses tumour growth in vitro and in vivo. Future studies are needed to determine whether RANKL is important for the malignant transformation or transition from GCNIS to invasive tumours.