Real-world drug utilization and treatment patterns in patients with tenosynovial giant cell tumors in the USA

Aim: Real-world treatment patterns in tenosynovial giant cell tumor (TGCT) patients remain unknown. Pexidartinib is the only US FDA-approved treatment for TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Objective: To characterize drug utilization and treatment patterns in TGCT patients. Methods: In a retrospective observational study using IQVIA's linked prescription and medical claims databases (2018-2021), TGCT patients were stratified by their earliest systemic therapy claim (pexidartinib [N = 82] or non-FDA-approved systemic therapy [N = 263]). Results: TGCT patients treated with pexidartinib versus non-FDA-approved systemic therapies were predominantly female (61 vs 50.6%) and their median age was 47 and 54 years, respectively. Pexidartinib-treated patients had the highest 12-month probability of remaining on treatment (54%); 34.1% of pexidartinib users had dose reduction after their first claim. Conclusion: This study provides new insights into the unmet need, utilization and treatment patterns of systemic therapies for the treatment of TGCT patients.

Understanding Sociodemographic Factors among Hispanics Through a Population-Based Study on Testicular Cancer in Mexico

Testicular cancer (TCa) is a rare malignancy affecting young men worldwide. Sociodemographic factors, especially socioeconomic level (SEL) and healthcare access, seem to impact TCa incidence and outcomes, particularly among Hispanic populations. However, limited research has explored these variables in Hispanic groups. This study aimed to investigate sociodemographic and clinical factors in Mexico and their role in health disparities among Hispanic TCa patients. We retrospectively analyzed 244 Mexican TCa cases between 2007 and 2020 of a representative cohort with diverse social backgrounds from a national reference cancer center. Logistic regression identified risk factors for fatality: non-seminoma histology, advanced stage, and lower education levels. Age showed a significant trend as a risk factor. Patient delay and healthcare distance lacked significant associations. Inadequate treatment response and chemotherapy resistance were more likely in advanced stages, while higher education positively impacted treatment response. Cox regression highlighted non-seminoma histology, below-median SEL, higher education, and advanced-stage survival rates. Survival disparities emerged based on tumor histology and patient SEL. This research underscores the importance of comprehensive approaches that integrate sociodemographic, biological, and environmental factors to address health disparities improving outcomes through personalized interventions in Hispanic individuals with TCa.

Supporting patients in the transition to the revised pexidartinib dosing regimen: perspectives from the multidisciplinary clinical and allied health professional team

Pexidartinib is a colony-stimulating factor-1 receptor inhibitor approved in the United States for treatment of adult patients with symptomatic tenosynovial giant cell tumor (TGCT) associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Because of the risk of severe and potentially fatal hepatotoxicity, pexidartinib is only available through a Risk Evaluation and Mitigation Strategy (REMS) program. Pexidartinib pharmacokinetics are influenced by the fat content of meals: compared with the fasted state, consuming a high-fat meal with pexidartinib increases pexidartinib absorption by 100%; a low-fat meal increases absorption by approximately 60%. Pexidartinib was initially authorized to be taken at 800 mg/day on an empty stomach; therefore, if this same dose of pexidartinib is taken with food, there is a risk of overexposure and potential toxicity. To reduce the risk of hepatotoxicity and improve patient compliance, pexidartinib has undergone a revised dosing regimen, from 800 mg/day (400 mg twice daily) fasted to 500 mg/day (250 mg twice daily) with a low-fat meal (approximately 11-14 g of total fat). The objective of this report is to educate clinical and allied health professionals on the revised dosing regimen and the importance of patient compliance with a low-fat meal. Healthcare professionals need to understand the rationale for the switch from pexidartinib dosing on an empty stomach to dosing with a low-fat meal and how meal composition and timing influence pharmacokinetics. Finally, we provide guidance for the healthcare team of prescribing providers, nurses, pharmacists, and dietitians who are caring for patients with TGCT on pexidartinib. It is important for healthcare providers to deliver consistent messaging on the low-fat meal requirement and help patients fit pexidartinib into their regular meal schedules. Consulting a dietitian may be helpful for patients, especially those with complex dietary needs. We provide an overview of the roles and responsibilities of each healthcare professional and outline steps to best support patients, including key questions and answers related to the revised dosing regimen. This report provides the information necessary to guide the multidisciplinary team caring for patients with TGCT and to support them through the pexidartinib dosing regimen change.

Outcomes of Tenosynovial Giant Cell Tumor of the Foot and Ankle

BACKGROUND

Tenosynovial giant cell tumor (TGCT) is a benign proliferative disease affecting synovial membranes. There are 2 forms, localized (L-TGCT) and diffuse (D-TGCT), which although histologically similar behave differently. It is locally invasive and is treated in most cases by operative excision. The aim of this study was to assess current practice, how the patients' presentation affected their outcome, as well as review the recurrence rates and complications.

METHODS

A retrospective analysis of 123 cases was performed in patients treated between 2003 and 2019 with TGCT of the foot and/or ankle. Data were collected on age at presentation, radiologic pattern of disease, location of disease, treatment provided, and recurrence rates. The minimum follow-up was 2 years with a mean of 7.7 years.

RESULTS

There were 61.7% female patients with a mean age of 39 (range, 11-76) years. L-TGCT accounted for 85 (69.1%) cases and D-TGCT for 38 (30.9%). The most prevalent preoperative symptoms were a palpable mass (78/123) and pain (65/123). Radiologically confirmed recurrence in the operative group was noted in 14.5% (16/110) cases. This comprised 4% (3/75) of operatively treated L-TGCT and 37% (13/35) of operatively treated D-TGCT. Patients with pain on presentation and those with erosive changes on presenting magnetic resonance imaging (MRI) were more likely to have persistent postoperative pain (P < .001 for both). Where patients had both preoperative pain and erosive changes, 57.1% had postoperative pain. Thirteen cases were managed nonoperatively where symptoms were minimal, with 1 case requiring surgery at a later date.

CONCLUSION

Outcomes of TGCT management are dependent on the disease type, extent of preoperative erosive changes, and presence of preoperative pain. These data are useful for counseling patients regarding the outcomes of surgical intervention and help guide the timing of intervention.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

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.

Dosing Recommendation Based on the Effects of Different Meal Types on Pexidartinib Pharmacokinetics in Healthy Subjects: Implementation of Model-informed Drug Development Strategy

Pexidartinib, an oral small molecule inhibitor of the colony-stimulating factor 1 receptor, is approved for treatment of adults with symptomatic tenosynovial giant cell tumor associated with severe morbidity or functional limitations and not amenable to improvement with surgery. The original dosing regimen is 400 mg of pexidartinib (2 × 200-mg capsules) twice daily, administered on an empty stomach at least 1 hour before or 2 hours after a meal or snack. Because pexidartinib is likely to be taken over an extended period of time, the ability to take pexidartinib with a meal would simplify timing of administration and potentially improve compliance. Since administering 400 mg of pexidartinib with a low-fat meal increases exposure by ≈60% relative to the fasted state, administering 250 mg of pexidartinib with a low-fat meal (low-fat meal dosing regimen) was predicted to achieve an exposure similar to 400 mg administered during a fasted state (original dosing regimen). Based on clinical trial simulations with two one-sided t-tests and bootstrapping (ie, resampling) analyses, a bioequivalence study (n = 24) would have >90% power to conclude that the original dosing regimen (400 mg fasted twice daily) and the low-fat meal dosing regimen (250 mg with a low-fat meal twice daily) are bioequivalent. This report provides the outcome of the implementation of the model-informed drug development strategy to recommend and justify a low-fat meal dosing regimen for pexidartinib that has the potential to improve patient compliance while maintaining drug exposure.

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

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

One-Stage Synovectomies Result in Improved Short-Term Outcomes Compared to Two-Stage Synovectomies of Diffuse-Type Tenosynovial Giant Cell Tumor (D-TGCT) of the Knee: A Multicenter, Retrospective, Cohort Study

Diffuse-type tenosynovial giant cell tumors' (D-TGCTs) intra- and extra-articular expansion about the knee often necessitates an anterior and posterior surgical approach to facilitate an extensive synovectomy. There is no consensus on whether two-sided synovectomies should be performed in one or two stages. This retrospective study included 191 D-TGCT patients from nine sarcoma centers worldwide to compare the postoperative short-term outcomes between both treatments. Secondary outcomes were rates of radiological progression and subsequent treatments. Between 2000 and 2020, 117 patients underwent one-stage and 74 patients underwent two-stage synovectomies. The maximum range of motion achieved within one year postoperatively was similar (flexion 123-120°, p = 0.109; extension 0°, p = 0.093). Patients undergoing two-stage synovectomies stayed longer in the hospital (6 vs. 4 days, p < 0.0001). Complications occurred more often after two-stage synovectomies, although this was not statistically different (36% vs. 24%, p = 0.095). Patients treated with two-stage synovectomies exhibited more radiological progression and required subsequent treatments more often than patients treated with one-stage synovectomies (52% vs. 37%, p = 0.036) (54% vs. 34%, p = 0.007). In conclusion, D-TGCT of the knee requiring two-side synovectomies should be treated by one-stage synovectomies if feasible, since patients achieve a similar range of motion, do not have more complications, but stay for a shorter time in the hospital.

Role of colony-stimulating factor 1 in the neoplastic process of tenosynovial giant cell tumor

Tenosynovial giant cell tumors (TGCTs) are rare, locally aggressive, mesenchymal neoplasms, most often arising from the synovium of joints, bursae, or tendon sheaths. Surgical resection is the first-line treatment, but recurrence is common, with resulting impairments in patients' mobility and quality of life. Developing and optimizing the role of systemic pharmacologic therapies in TGCT management requires an understanding of the underlying disease mechanisms. The colony-stimulating factor 1 receptor (CSF1R) has emerged as having an important role in the neoplastic processes underlying TGCT. Lesions appear to contain CSF1-expressing neoplastic cells derived from the synovial lining surrounded by non-neoplastic macrophages that express the CSF1R, with lesion growth stimulated by both autocrine effects causing proliferation of the neoplastic cells themselves and by paracrine effects resulting in recruitment of CSF1 R-bearing macrophages. Other signaling pathways with evidence for involvement in TGCT pathogenesis include programmed death ligand-1, matrix metalloproteinases, and the Casitas B-cell lymphoma family of ubiquitin ligases. While growing understanding of the pathways leading to TGCT has resulted in the development of both regulatory approved and investigational therapies, more detail on underlying disease mechanisms still needs to be elucidated in order to improve the choice of individualized therapies and to enhance treatment outcomes.

Discovery of vimseltinib (DCC-3014), a highly selective CSF1R switch-control kinase inhibitor, in clinical development for the treatment of Tenosynovial Giant Cell Tumor (TGCT)

Based on knowledge of kinase switch-control inhibition and using a combination of structure-based drug design and standard medicinal chemistry principles, we identified a novel series of dihydropyrimidone-based CSF1R kinase inhibitors displaying exquisite selectivity for CSF1R versus a large panel of kinases and non-kinase protein targets. Starting with lead compound 3, an SAR optimization campaign led to the discovery of vimseltinib (DCC-3014; compound 20) currently undergoing clinical evaluation for the treatment of Tenosynovial Giant Cell Tumor (TGCT), a locally aggressive benign tumor associated with substantial morbidity. 2021 Elsevier ltd. All rights reserved.

The seminal plasma microbiome of men with testicular germ cell tumours described by small RNA sequencing

BACKGROUND

It has been estimated that microorganisms are involved in the pathogenesis of approximately 20% of all cancers. Testicular germ cell tumours (TGCTs) are the most common type of malignancy in young men and arise from the precursor cell, Germ Cell Neoplasia in Situ (GCNIS). The microbiome of seminal plasma and testicular tissue has not been thoroughly investigated in regard to TGCTs.

OBJECTIVES

To investigate the differences in the seminal plasma microbiome between men with TGCT or GCNIS-only compared with controls.

MATERIALS AND METHODS

The study population consisted of patients with GCNIS-only (n = 5), TGCT (n = 18), and controls (n = 25) with different levels of sperm counts in the ejaculate. RNA was isolated from the seminal plasma and sequenced. Reads not mapping to the human genome were aligned against a set of 2784 bacterial/archaeal and 4336 viral genomes using the Kraken pipeline.

RESULTS

We identified reads from 2172 species and most counts were from Alteromonas mediterranea, Falconid herpesvirus 1, and Stigmatella aurantiaca. Six species (Acaryochloris marina, Halovirus HGTV-1, Thermaerobacter marianensis, Thioalkalivibrio sp. K90mix, Burkholderia sp. YI23, and Desulfurivibrio alkaliphilus) were found in significantly (q-value <0.05) higher levels in the seminal plasma of TGCT and GCNIS-only patients compared with controls. In contrast, Streptomyces phage VWB, was found at significantly higher levels among controls compared with TGCT and GCNIS-only patients combined.

DISCUSSION

Often the microbiome is analysed by shotgun or 16S ribosomal sequencing whereas our present data builds on small RNA sequencing. This allowed us to identify more viruses and phages compared to previous studies, but also makes the results difficult to directly compare.

CONCLUSION

Our study is the first to report identification of the microbiome species in seminal plasma of men with TGCT and GCNIS-only, which potentially could be involved in the pathogenesis of TGCTs. Further studies are, however, needed to confirm our findings. This article is protected by copyright. All rights reserved.

Long-term follow-up of nilotinib in patients with advanced tenosynovial giant cell tumours: Long-term follow-up of nilotinib in TGCT

BACKGROUND

Diffuse-type tenosynovial giant cell tumour (D-TGCT) is a non-malignant but locally aggressive tumour driven by overexpression of colony-stimulating factor-1 (CSF1). CSF1R inhibitors are potential therapeutic strategies for patients not amenable to surgery. We report here the long-term outcome of nilotinib in patients with advanced D-TGCT treated within a phase II prospective international study (ClinicalTrials.gov: NCT01261429).

METHODS

Patients were enrolled between December 2010-September 2012 at 11 cancer centres. Eligible patients had histologically confirmed D-TGCT, not amenable to surgery. Patients received nilotinib until evidence of progression, toxicity or a maximum of one year. Long-term data were retrospectively collected after the completion of the phase II trial. Patients with nilotinib treatment ≥12 weeks and follow-up ≥12 months were included for long-term analysis.

RESULTS

Forty-eight of 56 enrolled patients were included. Median treatment duration was 11 months; 31 (65%) patients completed the treatment protocol. After 102 months of follow-up (median; range 12-129), 25 patients (52%) had progression. The median progression-free survival (PFS) was 77 months. The five-year PFS rate was 53%. Fifteen patients (n = 15/46; 33%) experienced clinical worsening after 11 months (median). Twenty-seven patients (58%) received additional treatment, after which eleven patients (n = 11/27; 41%) had a second relapse. Nine patients required a subsequent treatment, primarily other CSF1R inhibitors (n = 6/9; 67%). No unfavourable long-term effects were observed.

CONCLUSION

This long-term analysis of nilotinib for advanced D-TGCT showed that about half of the patients had progression and underwent additional treatment after 8.5 years follow-up. Contrarily, several patients had ongoing disease control after limited treatment duration, demonstrating the mixed effect of nilotinib.

LINC00313 regulates the metastasis of testicular germ cell tumors through epithelial-mesenchyme transition and immune pathways

Testicular germ cell tumor (TGCT) is a relatively rare entity tumor, accounting for only 1% of all male cancers. However, it is the most common solid tumor in young men between 15 and 34 years old. Long noncoding RNAs (lncRNAs) are involved in various physiological and pathological processes. However, the functions of lncRNAs in TGCT have only rarely been investigated. LncRNAs associated with TGCT were identified using Gene Expression Omnibus (GEO) database and UCSC XENA database data mining. The effects of LINC00313 on NCCIT cell migration and invasion were evaluated in transwell assays. The expression levels of epithelial-mesenchyme transition (EMT)-related proteins in cells knockdown of LINC00313 were analyzed by Western blot. Correlation analyses between lncRNA LINC00313 expression and copy number variation (CNV) and immune cell infiltration were carried out using The Cancer Genome Atl as (TCGA) data. The effect of Panobinostatin targeting LINC00313 in TGCT cells was investigated. We observed higher LINC00313 expression in TGCT. The migratory and invasive properties of TGCT cells were augmented by LINC00313, likely via its effects on modulating the expression of epithelial-mesenchyme transition (EMT) related proteins: CTNNB1, ZEB1, CDH2, Snail and VIM. Moreover, LINC00313 expression and CNV correlated negatively with the infiltration of immune cells. In addition, Panobinostat might be a possible candidate drug to target LINC00313 in TGCT. LINC00313 performs important pro-migration and invasion functions in the pathogenesis of TGCT. LINC00313 could be used as diagnostic, prognostic, immune marker and therapeutic target to develop effective treatment of TGCT.

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.

Effect of Mild and Moderate Hepatic Impairment (defined by Child Pugh classification and National Cancer Institute-Organ Dysfunction Working Group criteria) on Pexidartinib Pharmacokinetics

Pexidartinib is a novel oral small‐molecule tyrosine kinase inhibitor targeting the colony‐stimulating factor 1 receptor. Pexidartinib undergoes extensive hepatic metabolism via multiple cytochrome P450 and uridine 5'‐diphospho‐glucuronosyl transferase enzymes, with ZAAD‐1006a as the only major metabolite in human plasma. As pexidartinib is extensively metabolized, hepatic impairment (HI) could lead to increased exposure to pexidartinib. The objective of the two phase 1, open‐label studies was to determine the pharmacokinetics of pexidartinib after a single 200‐mg dose in subjects with mild and moderate HI, based on Child–Pugh classification (PL3397‐A‐U123: 8 mild HI and 8 moderate HI vs 16 matched healthy controls) and National Cancer Institute Organ Dysfunction Working Group (NCI‐ODWG) criteria (PL3397‐A‐U129: 8 moderate HI versus 8 matched healthy controls [NCT04223635]). Based on Child–Pugh classification, exposure to pexidartinib (maximum observed concentration [C_max], area under the plasma concentration–time curve up to the last measurable concentration [AUC_last], and extrapolated to infinity [AUC_inf]) was similar in subjects with mild and moderate HI and in respective matched healthy controls, whereas ZAAD‐1006a exposure (AUC) was approximately 27% to 28% and 41% to 48% higher in mild and moderate HI, respectively. According to NCI‐ODWG criteria, total pexidartinib exposure was 42% to 46% higher in subjects with moderate HI, compared with healthy controls, and total ZAAD‐1006a exposure was 70% to 79% higher for subjects with moderate HI, compared with matched healthy controls with normal hepatic function. These findings were used to develop appropriate dose recommendations in patients with hepatic impairment.

Hypomethylation-driven AKT Serine/Threonine Kinase 3 promotes testicular germ cell tumors proliferation and negatively correlates to immune infiltration

AKT Serine/Threonine Kinase 3 (AKT3) has been reported to play an important role in different tumors. However, its clinical value, biological function, and molecular mechanism in testicular germ cell tumors (TGCT) remains unclear. In the current study, we applied the Gene Set Cancer Analysis (GSCA), UCSC XENA, Gene Expression Omnibus (GEO), the Human Protein Atlas (HPA), LinkedOmics, DiseaseMeth version 2.0, TISIDB, and other databases for TGCT data mining. Then, we investigated AKT3’s mechanism of action and clinical survival significance via bioinformatics followed by in vitro experiments. We found that AKT3 was upregulated and had frequent copy number amplifications in TGCT, which were associated with poor survival outcomes of patients. On the other hand, mutations that led to AKT3 loss-of-function were correlated to a better prognosis in patients. Moreover, AKT3 silencing significantly inhibited the proliferation, DNA synthesis and colony formation of NCCIT cells (a TGCT cell line). AKT3 might participate in TGCT progression through multiple signaling pathways, such as ErbB, oxidative phosphorylation, and affecting tumor immune infiltration. Also, the upregulation of AKT3 mRNA expression might be driven by the hypomethylation of its promoter region. Overall, AKT3 is a potential TGCT oncogene and can be further used as a therapeutic target.

SPOP suppresses testicular germ cell tumors progression through ubiquitination and degradation of DPPA2

Dysregulation of the ubiquitin-proteasome pathway is strongly associated with cancer initiation and progression. Speckle-type POZ(pox virus and zinc finger protein) protein(SPOP) is an adapter protein of CUL3-based E3 ubiquitin ligase complexes. Gene expression profiling from the Cancer Genome Atlas (TCGA) suggests that SPOP is downregulated in testicular germ cell tumors (TGCTs), but the specific contribution of this protein remains to be explored. In this study, we show that the germ line-specific factor DPPA2 was identified as a proteolytic substrate for the SPOP-CUL3-RBX1 E3 ubiquitin-ligase complex. SPOP specifically binds to a SPOP-binding consensus (SBC) degron located in DPPA2 and targets DPPA2 for degradation via the ubiquitin-proteasome pathway. SPOP downregulation increases the expression of pluripotency markers OCT4 and Nanog but decreases that of early differentiation marker gene Fst. This effect is partly dependent on its activity toward DPPA2. In addition, the dysregulation of SPOP-DPPA2 axis contributes to the malignant transformation phenotypes of TGCT cells.

Testicular Germ Cell Tumors Acquire Cisplatin Resistance by Rebalancing the Usage of DNA Repair Pathways

Simple Summary

Germ cell tumors are a model of curable solid tumors due to their unique sensitivity to cisplatin-based chemotherapy. Patients are typically young adults, and despite high cure rate, about 20% of them do not achieve remission or relapse, and 50% of them succumb to the disease. The mechanisms behind their resistance to therapy are largely unknown. By using Testicular Germ Cell Tumor (TGCT) cell lines as a model, we investigated the mechanism of acquired resistance to cisplatin. We demonstrated that resistance occurred by a fine modulation of the DNA repair pathway choice. Namely, in resistant cells, repair of double-strand breaks by non-homologous end joining was dampened by the reduced expression of TP53-binding protein 1 (53BP1) and DNA-dependent protein kinase (DNA-PKcs). However, cisplatin-induced damage was repaired efficiently by homologous recombination. Additionally, we demonstrate that pharmacological inhibition of poly (ADP-ribose) polymerase (PARP) combined with cisplatin had an additive/synergistic effect on cisplatin-resistant cells, which represents the proof of concept for introducing PARP inhibitors in salvage therapy.

Abstract

Despite germ cell tumors (GCTs) responding to cisplatin-based chemotherapy at a high rate, a subset of patients does not respond to treatment and have significantly worse prognosis. The biological mechanisms underlying the resistance remain unknown. In this study, by using two TGCT cell lines that have acquired cisplatin resistance after chronic exposure to the drug, we identified some key proteins and mechanisms of acquired resistance. We show that cisplatin-resistant cell lines had a non-homologous end-joining (NHEJ)-less phenotype. This correlated with a reduced basal expression of TP53-binding protein 1 (53BP1) and DNA-dependent protein kinase (DNA-PKcs) proteins and reduced formation of 53BP1 foci after cisplatin treatment. Consistent with these observations, modulation of 53BP1 protein expression altered the cell line’s resistance to cisplatin, and inhibition of DNA-PKcs activity antagonized cisplatin cytotoxicity. Dampening of NHEJ was accompanied by a functional increase in the repair of DNA double-strand breaks (DSBs) by the homologous recombination repair pathway. As a result, cisplatin-resistant cells were more resistant to PARP inhibitor (PARPi) monotherapy. Moreover, when PARPi was given in combination with cisplatin, it exerted an additive/synergistic effect, and reduced the cisplatin dose for cytotoxicity. These results suggest that treatment of cisplatin-refractory patients may benefit from low-dose cisplatin therapy combined with PARPi.

Teratoma Growth Retardation by HDACi Treatment of the Tumor Embryonal Source

Simple Summary

Testicular germ cell tumors are the most common neoplasms in young male populations, with a rising incidence. Among them, teratomas may often be very aggressive and resistant to therapy. Our aim was to investigate the impact of two potential anti-tumor epigenetic drugs (Valproate and Trichostatin A) in a mammalian model of teratoma development from an early trilaminar mouse embryo. Both drugs applied to the embryonic tissue had a significant negative impact on the teratoma growth in a three-dimensional in vitro culture. However, Trichostatin A did not diminish some potentially dangerous features of teratomas in contrast to Valproate. This research is an original contribution to the basic knowledge of the origin and development of teratomas. Such knowledge is necessary for envisioning therapeutic strategies against human testicular tumors.

Abstract

Among testicular germ cell tumors, teratomas may often be very aggressive and therapy-resistant. Our aim was to investigate the impact of histone deacetylase inhibitors (HDACi) on the in vitro growth of experimental mouse teratoma by treating their embryonic source, the embryo-proper, composed only of the three germ layers. The growth of teratomas was measured for seven days, and histopathological analysis, IHC/morphometry quantification, gene enrichment analysis, and qPCR analysis on a selected panel of pluripotency and early differentiation genes followed. For the first time, within teratomas, we histopathologically assessed the undifferentiated component containing cancer stem cell-like cells (CSCLCs) and differentiated components containing numerous lymphocytes. Mitotic indices were higher than apoptotic indices in both components. Both HDACi treatments of the embryos-proper significantly reduced teratoma growth, although this could be related neither to apoptosis nor proliferation. Trichostatin A increased the amount of CSCLCs, and upregulated the mRNA expression of pluripotency/stemness genes as well as differentiation genes, e.g., T and Eomes. Valproate decreased the amount of CSCLCs, and downregulated the expressions of pluripotency/stemness and differentiation genes. In conclusion, both HDACi treatments diminished the inherent tumorigenic growth potential of the tumor embryonal source, although Trichostatin A did not diminish the potentially dangerous expression of cancer-related genes and the amount of CSCLC.

Population Pharmacokinetic Analysis of Pexidartinib in Healthy Subjects and Patients With Tenosynovial Giant Cell Tumor or Other Solid Tumors

Pexidartinib is a kinase inhibitor that induces tumor response and improvements in symptoms and functional outcomes in adult patients with symptomatic tenosynovial giant cell tumor (TGCT). A population pharmacokinetic (PK) model for pexidartinib and its metabolite, ZAAD, was developed, and effects of demographic and clinical factors on the PK of pexidartinib and ZAAD were estimated. The analysis included pooled data from 7 studies in healthy volunteers (N = 159) and 2 studies in patients with TGCT or other solid tumors (N = 216). A structural 2‐compartment model with sequential zero‐ and first‐order absorption and lag time, and linear elimination from the central compartment adequately described pexidartinib and ZAAD PKs. Clearance of pexidartinib was estimated at 5.83 L/h in a typical patient with reference covariates (male, non‐Asian, weight = 80 kg, creatinine clearance ≥90 mL/min, aspartate aminotransferase ≤80 U/L, and total bilirubin ≤20.5 μmol/L). In the covariate analysis, Asians and healthy subjects had modestly lower pexidartinib exposure (21% decrease each) in terms of steady‐state area under the curve values from 0 to 24 hours (AUC_0‐24,ss). Effects of body weight, sex, and hepatic function parameters on pexidartinib AUC_0‐24,ss were generally <20%. Patients with TGCT with mild renal impairment were predicted to have approximately 23% higher AUC_0‐24,ss than those with normal renal function. The effects of covariates on ZAAD exposure were similar to those on pexidartinib. These results indicate small and generally clinically nonmeaningful effects of patient demographic and clinical characteristics on pexidartinib and ZAAD PK profiles.

Establishment and characterization of a novel cell line, NCC-TGCT1-C1, derived from a patient with tenosynovial giant cell tumor

Tenosynovial giant cell tumor (TGCT) is a mesenchymal tumor arising from the synovium of tendon sheath and joints, characterized by translocation t(1;2)(p13;q37). Clinical behaviors of TGCT range from favorable to locally aggressive and further research is required to lead the identification of novel therapeutic avenues for TGCT. Patient-derived cell lines are an indispensable tool for interrogating molecular mechanisms underlying the progression of disease. However, only one TGCT cell line is currently available from cell banks, and a paucity of adequate patient-derived cells hinders basic and translational research. This study aimed to establish a novel cell line of TGCT. To this end, a novel cell line, NCC-TGCT1-C1 was established from the primary tumor tissue of a 40-year-old female patient with TGCT. The cells exhibited translocation t(1;2)(p13;q37), generating COL6A3-CSF1 fusion gene. The cells were maintained as a monolayer culture through more than 30 passages over 12 months. The cells exhibited continuous growth and the ability for spheroid formation and invasion. When used in a high-throughput assay to evaluate the anti-proliferative effects of 164 anticancer drugs, the cells responded strongly to a kinase inhibitor such as gefitinib, and mitoxantrone. Our results indicate that the novel TGCT cell line, designated NCC-TGCT1-C1, was successfully established and could be used to study TGCT development and the effects of anticancer agents.

Pexidartinib: first approved systemic therapy for patients with tenosynovial giant cell tumor

Pexidartinib is an orally administered small molecule tyrosine kinase inhibitor. Phase III ENLIVEN study results provided clinical evidence for US FDA approval for treatment of adult patients with symptomatic tenosynovial giant cell tumor associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Recommended dosage is 400 mg orally twice daily on an empty stomach. Long-term follow-up in pooled analyses showed increased response rates compared with those observed in ENLIVEN. Patients on pexidartinib also experience meaningful improvements in range of motion. Side effects associated with pexidartinib are generally manageable; however, there is a risk of potentially life-threatening mixed or cholestatic hepatotoxicity and pexidartinib has a Risk Evaluation and Mitigation Strategy (REMS) program to ensure appropriate monitoring.

Psychometric properties of a custom Patient-Reported Outcomes Measurement Information System (PROMIS) physical function short form and worst stiffness numeric rating scale in tenosynovial giant cell tumors

Purpose

The purpose of this study was to evaluate the psychometric properties of the PROMIS-Physical Function (PF) and Worst Stiffness Numeric Rating Scale (NRS) among patients with tenosynovial giant cell tumors (TGCT).

Methods

Measurement properties of the customized lower extremity (LE) and upper extremity (UE) PROMIS-PF scales and Worst Stiffness NRS were assessed using data from the Phase 3 ENLIVEN trial (n = 120). Anchor- and distribution-based analyses were utilized to derive a responder threshold for meaningful change over time. The Patient Global Rating of Concept (PGRC)-Physical Functioning and Patient Global Impression of Change (PGIC)-Stiffness served as anchors. Responsiveness and responder threshold analyses were from baseline to week 25.

Results

Cronbach’s alpha values for internal consistency reliability were 0.93 and 0.91 for the PROMIS-PF LE and UE, respectively. Test-retest reliability intra-class correlation coefficients were > 0.75 for both instruments. Convergent validity for both instruments was supported by moderate to strong correlations (≥0.30) with the Brief Pain Inventory and EQ-5D. Known-groups validity was established between subgroups stratified by pain level (p < 0.05). Responsiveness was supported by evaluating change scores among different levels of change in PGRC-Physical Functioning and PGIC-Stiffness (overall F values < 0.001). Triangulation of responder definition analyses resulted in a threshold of ≥3 for the PROMIS-PF and ≥ 1 for the Worst Stiffness NRS.

Conclusion

This study is the first to establish the psychometric properties of patient-reported outcome measures in TGCT. The evidence demonstrates that the PROMIS-PF and Worst Stiffness NRS have good reliability, validity, and responsiveness, and provides guidance for the interpretation of meaningful change.

Tenosynovial giant cell tumor of the suboccipital region - A rare, benign neoplasm in this location

Tenosynovial giant cell tumors (TGCTs) are benign neoplasms that arise from the synovium of tendon sheaths, bursae, and joints. We report a rare presentation of TGCT involving the suboccipital spine.

Pexidartinib for the treatment of adult patients with symptomatic tenosynovial giant cell tumor: safety and efficacy

INTRODUCTION

Tenosynovial giant cell tumor (TGCT) is a benign clonal neoplastic proliferation arising from the synovium often causing pain, swelling, joint stiffness, and reduced quality of life. The optimal treatment strategy in patients with diffuse-type TGCT (dt-TGCT) is evolving. Surgery is the main treatment, with a high recurrence rate and surgery-related morbidity. Radiotherapy is associated with important side effects. TGCT cells overexpress colony-stimulating factor 1 (CSF1). Pexidartinib (Turalio™) is a selective CSF1 R inhibitor, which was recently approved by the FDA for the treatment of TGCT.

AREAS COVERED

This article reviews the pharmacological properties, clinical efficacy, and safety of pexidartinib.

EXPERT OPINION

Pexidartinib was effective with an acceptable safety profile for advanced TGCT in phase I-III studies. The phase III trial (ENLIVEN) in unresectable TGCT met its primary endpoints of overall response rate. These results led to FDA approval for this TGCT population. Mixed or cholestatic hepatotoxicity was observed in rare cases. For this reason, pexidartinib is currently available only through a Risk Evaluation and Mitigation Strategy (REMS) Program in the USA. TGCT significantly impairs patients' quality of life. The approval of pexidartinib has changed the therapeutic armamentarium for this condition. However, strict monitoring of liver function is warranted.

Distinct telomere length and molecular signatures in seminoma and non-seminoma of testicular germ cell tumor

Testicular germ cell tumors (TGCTs) are classified into two main subtypes, seminoma (SE) and non-seminoma (NSE), but their molecular distinctions remain largely unexplored. Here, we used expression data for mRNAs and microRNAs (miRNAs) from The Cancer Genome Atlas (TCGA) to perform a systematic investigation to explain the different telomere length (TL) features between NSE (n = 48) and SE (n = 55). We found that TL elongation was dominant in NSE, whereas TL shortening prevailed in SE. We further showed that both mRNA and miRNA expression profiles could clearly distinguish these two subtypes. Notably, four telomere-related genes (TelGenes) showed significantly higher expression and positively correlated with telomere elongation in NSE than SE: three telomerase activity-related genes (TERT, WRAP53 and MYC) and an independent telomerase activity gene (ZSCAN4). We also found that the expression of genes encoding Yamanaka factors was positively correlated with telomere lengthening in NSE. Among them, SOX2 and MYC were highly expressed in NSE versus SE, while POU5F1 and KLF4 had the opposite patterns. These results suggested that enhanced expression of both TelGenes (TERT, WRAP53, MYC and ZSCAN4) and Yamanaka factors might induce telomere elongation in NSE. Conversely, the relative lack of telomerase activation and low expression of independent telomerase activity pathway during cell division may be contributed to telomere shortening in SE. Taken together, our results revealed the potential molecular profiles and regulatory roles involving the TL difference between NSE and SE, and provided a better molecular understanding of this complex disease.

Evaluation of Circulating miRNA Biomarkers of Testicular Germ Cell Tumors during Therapy and Follow-up-A Copenhagen Experience

New microRNA-based serum biomarkers (miRNA-367-3p, -371a-3p, -372-3p, and -373-3p) have shown great potential for the detection of testicular germ cell tumors (TGCTs), but few studies have investigated the clinical utility and performance of these tests in treatment monitoring. In this study, circulating miRNA levels were measured, together with serum tumor markers alpha-fetoprotein (AFP), β-subunit of human chorionic gonadotropin (β-HCG) and lactate dehydrogenase (LDH) in 406 consecutive blood samples obtained during the treatment and follow-up of 52 TGCT patients at the Copenhagen University Hospital. After testing three different methods of RNA isolation from peripheral blood and PCR quantification in a subset of samples (n = 15), the best performing setup of targeted isolation of miRNAs inside and outside exosomes was selected to analyze all samples. At primary diagnosis, the miRNAs significantly outperformed the serum tumor markers, with a sensitivity and specificity of 78% and 100% (based on 40 patients), respectively. The picture was not as clear when patient trajectories were investigated, with both positive and negative signals for miRNAs and serum tumor markers. To establish whether measuring miRNAs adds value beyond the primary diagnosis, large prospective clinical trials comparing miRNAs and classical tumor markers during the treatment and follow-up of TGCT patients are needed.

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.

Expression of PD-L1 in mononuclear cells, multinucleated cells, and foam cells in tenosynovial giant cell tumors

Tenosynovial giant cell tumor (TGCT) is a rare, proliferative and inflammatory disease with activation of colony stimulating factor 1 (CSF1) expression, and exhibits abnormal proliferation of mononuclear cells, multinucleated cells and foam cells. PD-L1 inhibitors represent a promising strategy in a variety of tumors. However, PD-L1 expression has never been studied in CSF1 activated TGCT. In this study, we determined the expression of programmed cell death ligand 1 (PD-L1) in 40 TGCT cases by immunohistochemistry and evaluated its clinical significance. We found that PD-L1 was positively expressed in 52.5% of all patients, and among them, the mononuclear cells, multinucleated cells, and foam cells with positive PD-L1 expression were observed in 21 (52.5%), 10 (25.0%), and 7 (17.5%) patients, respectively. The mononuclear cells and foam cells exhibited PD-L1 expression on the membrane or in the cytoplasm, and the multinucleated cells showed membranous PD-L1 expression. In addition, the PD-L1-positive mononuclear cells, multinucleated cells, and foam cells co-expressed CD68. Moreover, the patients with positive PD-L1 expression had a larger tumor size than those with negative PD-L1 expression. We further found that the foam cells of human coronary atherosclerosis also exhibited the expression of PD-L1 in two of three patients. These findings provide valuable evidence that PD-L1 is highly positive in CSF1-activated TGCT, and treatment with anti-PD-L1 agents may be a valuable therapeutic option for those diseases with PD-L1 expression on mononuclear cells, multinucleated cells, or foam cells.

The measurement of physical functioning among patients with Tenosynovial Giant Cell Tumor (TGCT) using the Patient-Reported Outcomes Measurement Information System (PROMIS)

Background

Tenosynovial giant cell tumor (TGCT), a rare, locally aggressive neoplasm of the synovium of joints and tendon sheaths, is associated with joint destruction, pain and swelling. Impacts on physical function (PF) vary depending on tumor size and location. The aim of this study was to identify relevant items, and demonstrate the content validity of custom measures of lower extremity PF from the Patient-Reported Outcomes Measurement Information System Physical Function Physical Function (PROMIS-PF) item bank among patients with TGCT.

Methods

Patients were recruited for qualitative research interviews to identify predominant TGCT symptoms and impacts. Patients completed a checklist to evaluate the relevance of each PROMIS-PF item. The publicly available PROMIS-PF item response theory (IRT) parameters were used to select items representing the range of the latent PF trait.

Results

Participants (n = 20) were 75% female, mean age 42.5 years. TGCTs were located in the knee (n = 15), hip (n = 3), and ankle (n = 2). Fifty-four PROMIS-PF items were identified as relevant by ≥20% of the participants. PF concepts discussed by participants during the qualitative interviews were also used to select relevant items. Selected items (n = 13) were used to create a physical function subscale specific to lower extremity tumors.

Conclusions

We describe a novel method of combining qualitative research and IRT-based item information to select a relevant and content valid subset of PROMIS-PF items to assess heterogeneous impacts on PF in TGCT, a rare disease population.

Electronic supplementary material

The online version of this article (10.1186/s41687-019-0099-0) contains supplementary material, which is available to authorized users.

Tenosynovial giant cell tumor: case report of a patient effectively treated with pexidartinib (PLX3397) and review of the literature

Background

Tenosynovial giant cell tumors (TGCTs) or giant cell tumors of tendon sheath are neoplasms that arise in the synovium. They can be categorized as nodular (localized) or diffuse type (D-TGCT). Historically, surgery has been the mainstay of therapy, but diffuse type disease recurs at a high rate and treatment often requires increasingly morbid procedures. Elucidation of the importance of the colony-stimulating factor (CSF1)/CSF1 receptor (CSF1R) pathway in the pathogenesis of this disease has created significant interest in targeting this pathway as a novel TGCT treatment approach. Pexidartinib, a selective tyrosine kinase inhibitor against CSF1R, showed an 83% disease control rate (52% with partial response and 31% with stable disease) in a recent phase 1 study of patients with TGCT.

Case presentation

We present an illustrative example of a TGCT patient who would have required a morbid operation who derived considerable clinical benefit from pexidartinib treatment. Her tumor volume decreased by 48% after 4 months of treatment, and 55 months after starting treatment the patient exhibits continued disease stability with minimal clinical symptoms, and significant improvement in functional status.

Conclusions

This case illustrates the effectiveness of systemic therapy in controlling a disease associated with high surgical morbidity. This approach may be especially useful in the treatment of extra-articular disease which often invades neurovascular bundles; as the effectiveness in metastatic disease is still unknown. In the future, systemic treatment for TGCT may be appropriate for the neoadjuvant setting to decrease disease burden prior to surgery with the aim of decreasing recurrence rates. However, properly designed prospective studies will need to be carried out to answer these questions.

Maternal use of personal care products during pregnancy and risk of testicular germ cell tumors in sons

BACKGROUND

The etiology of testicular germ cell tumors (TGCT) is poorly understood, however, exposure to endocrine disrupting chemicals (EDCs) may be related to increased risk. Personal care products, some of which contain EDCs, are widely used on a daily basis and are known to cross the placenta, be present in breastmilk, and are capable of inducing reproductive tract abnormalities. To determine the association between personal care product use during pregnancy and breastfeeding and TGCT risk, an analysis among mothers of TGCT cases and controls was conducted.

METHODS

The US Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) study enrolled TGCT cases and controls and their mothers between 2002 and 2005. The current analysis examined personal care product use during pregnancy among 527 mothers of TGCT cases and 562 mothers of controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression adjusting for identified covariates.

RESULTS

Maternal use of face lotion more than one time per week was associated with a significantly increased risk of TGCT (OR: 1.42, 95% CI: 1.08-1.86, p-trend: 0.01). None of the other products examined (perfume, hairspray, nail polish, hair dye, permanent wave, body lotion, deodorant, sunscreen) were associated with TGCT risk.

CONCLUSIONS

Frequent exposure to face lotion during pregnancy and while breastfeeding may be associated with increased TGCT risk. Further investigation into the endocrine disrupting effects of personal care products is warranted.

Chemotherapy-Induced Depletion of OCT4-Positive Cancer Stem Cells in a Mouse Model of Malignant Testicular Cancer

Testicular germ cell tumors (TGCTs) are among the most responsive solid cancers to conventional chemotherapy. To elucidate the underlying mechanisms, we developed a mouse TGCT model featuring germ cell-specific Kras activation and Pten inactivation. The resulting mice developed malignant, metastatic TGCTs composed of teratoma and embryonal carcinoma, the latter of which exhibited stem cell characteristics, including expression of the pluripotency factor OCT4. Consistent with epidemiological data linking human testicular cancer risk to in utero exposures, embryonic germ cells were susceptible to malignant transformation, whereas adult germ cells underwent apoptosis in response to the same oncogenic events. Treatment of tumor-bearing mice with genotoxic chemotherapy not only prolonged survival and reduced tumor size but also selectively eliminated the OCT4-positive cancer stem cells. We conclude that the chemosensitivity of TGCTs derives from the sensitivity of their cancer stem cells to DNA-damaging chemotherapy.

Validation of loci at 2q14.2 and 15q21.3 as risk factors for testicular cancer

Testicular germ cell tumor (TGCT), the most common cancer in men aged 18 to 45 years, has a strong heritable basis. Genome-wide association studies (GWAS) have proposed single nucleotide polymorphisms (SNPs) at a number of loci influencing TGCT risk. To further evaluate the association of recently proposed risk SNPs with TGCT at 2q14.2, 3q26.2, 7q36.3, 10q26.13 and 15q21.3, we analyzed genotype data on 3,206 cases and 7,422 controls. Our analysis provides independent replication of the associations for risk SNPs at 2q14.2 (rs2713206 at P = 3.03 × 10-2; P-meta = 3.92 × 10-8; nearest gene, TFCP2L1) and rs12912292 at 15q21.3 (P = 7.96 × 10-11; P-meta = 1.55 × 10-19; nearest gene PRTG). Case-only analyses did not reveal specific associations with TGCT histology. TFCP2L1 joins the growing list of genes located within TGCT risk loci with biologically plausible roles in developmental transcriptional regulation, further highlighting the importance of this phenomenon in TGCT oncogenesis.

The epigenetics of testicular germ cell tumors: looking for novel disease biomarkers

Testicular germ cell tumors (TGCT) are a group of heterogeneous, biologically diverse and clinically challenging neoplasms. Despite the relatively low incidence and mortality rates, a subgroup of patients with disseminated disease relapse after conventional therapy and have a dismal prognosis. Moreover, TGCT afflict mostly young men and have therapeutic peculiarities, with some patients showing resistance to cisplatin-based treatments and others being troubled by irreversible side effects, such as infertility. Most TGCT share a common tumorigenic pathway and are cytogenetically similar, making room for Epigenetics to explain its heterogeneity at pathological and clinical level. In this review, we summarize the foremost epigenetic alterations among TGCT focusing on their clinical potential as diagnostic, prognostic and predictive biomarkers.

Expression of microRNAs of C19MC in Different Histological Types of Testicular Germ Cell Tumour

BACKGROUND

Testicular germ cell tumours (TGCTs) are the most common tumours in men aged from 20 to 40 years, with a steadily increasing incidence. This study aimed to characterize the expression of the miRNA cluster C19MC in TGCT and to evaluate the suitability of a C19MC miRNA as a serum biomarker.

MATERIALS AND METHODS

By quantitative reverse transcription PCR, we measured the expression of miR-517a-3p, miR-519a-3p, and miR-519c 3p in tissue samples of 25 TGCTs and the level of miR-517a-3p in serum samples obtained pre- and postoperatively from the same patients.

RESULTS

We detected a significantly higher expression of C19MC miRNAs in non-seminomas than in seminomas and in clinical stages 2 and 3 than in stage 1 in both tissue and serum samples.

CONCLUSION

miRNAs of C19MC are overexpressed in more aggressive types of TGCT, suggesting they contribute to malignancy. Furthermore, they might serve as serum biomarkers for these types of TGCT.

Histological groups of human postpubertal testicular germ cell tumours harbour different genetic alterations

BACKGROUND

Testicular germ cell tumours are the most common malignancies in young males. Molecular biology studies of these tumours are often contradictory. Two histological groups, seminoma and non-seminoma, differ both morphologically and in malignant behaviour. Although a common cytogenetic feature is seen, namely the amplification of the 12p chromosomal region, the development mechanisms of less aggressive seminomas and more aggressive non-seminomas are unknown.

MATERIALS AND METHODS

Occurrence of structural genetic alterations was analyzed in 18 seminomas and 22 non-seminomas for genes involved in the malignant tumour phenotype: cadherin 1, Type 1, E-cadherin (Epithelial), CDH1; adenomatous polyposis coli, APC; NME/NM23 nucleoside diphosphate kinase 1, NME1; tumour protein P53, TP53; cyclin-dependent kinase inhibitor 2A, CDKN2A; retinoblastoma 1, RB1; RAD51 recombinase, RAD51; mutS homolog 2, MSH2; MutL homolog 1, MLH1; breast cancer 1, early onset, BRCA1; BCL2-Associated X Protein, BAX; ATP-Binding Cassette, Sub-Family G (WHITE), Member 2, ABCG2. Genetic alterations, loss of heterozygosity and microsatellite instability, were analyzed using restriction fragment or microsatellite repeat length polymorphisms.

RESULTS

A difference in genetic alteration occurrence between seminomas and non-seminomas was observed.

CONCLUSION

Occurrence of genetic alterations correlates with clinical behaviour of these tumours and may indicate that such alterations could occur early in the development of seminomas and non-seminomas.

Control of mammalian germ cell entry into meiosis

Germ cells are unique in undergoing meiosis to generate oocytes and sperm. In mammals, meiosis onset is before birth in females, or at puberty in males, and recent studies have uncovered several regulatory steps involved in initiating meiosis in each sex. Evidence suggests that retinoic acid (RA) induces expression of the critical pre-meiosis gene Stra8 in germ cells of the fetal ovary, pubertal testis and adult testis. In the fetal testis, CYP26B1 degrades RA, while FGF9 further antagonises RA signalling to suppress meiosis. Failsafe mechanisms involving Nanos2 may further suppress meiosis in the fetal testis. Here, we draw together the growing knowledge relating to these meiotic control mechanisms, and present evidence that they are co-ordinately regulated and that additional factors remain to be identified. Understanding this regulatory network will illuminate not only how the foundations of mammalian reproduction are laid, but also how mis-regulation of these steps can result in infertility or germline tumours.