Advances in radiation therapy for testicular seminoma.

PURPOSE: Novel techniques and advances in radiation therapy (RT) have been explored to treat testicular seminoma, a highly radiosensitive and curable histology. We evaluated the historical and current indications for radiation therapy (RT) in testicular seminoma. METHODS: A narrative literature review was performed. Studies of RT for testicular seminoma were included. Additionally, recent trials testing the use of combination or surgical therapies for clinical stage (CS) II were included. Search parameters included radiation therapy, testicular seminoma, surgery, and chemoradiation. Parameters and outcomes assessed were progression-free survival (PFS), overall survival (OS), acute toxicities, long-term sequelae, and rates of secondary malignancies. RESULTS: Practice defining and changing studies in the use or omission of radiation therapy for testicular seminoma were identified along with resultant changes in National Comprehensive Cancer Network (NCCN) and European guidelines. Recent trials in combined chemoradiation and upfront surgical approaches to CS II disease were reviewed. CONCLUSION: RT has historically been used as adjuvant treatment for CS I disease and is highly effective at treating CS II (A/B) testicular seminoma. The drive to maintain therapeutic efficacy and reduce acute and long-term side effects, namely secondary malignancies, is being tested using new radiation technologies, combined modality therapy in the form of chemoradiation and with upfront surgical approaches. Also, as guidelines now "strongly prefer" surveillance instead of adjuvant RT for CS I disease, the current CS II population comprises patients presenting with CS II disease ("de novo") and those who present with CSII after relapsing post orchiectomy for CS I ("relapsed"). Emerging evidence suggests that these two groups have different outcomes with respect to RT and chemoradiation. Consequently, future trials may need to sub-stratify according to these groups.

The role of primary retroperitoneal lymph node dissection in the treatment of stage II seminoma.

PURPOSE OF REVIEW: Stage II seminoma is responsive to chemo- or radiotherapy with a progression-free survival of 87-95% at 5 years but at the cost of short- and long-term toxicity. After evidence about these long-term morbidities emerged, four surgical cohorts investigating the role of retroperitoneal lymph node dissection (RPLND) as a treatment option for stage II disease were initiated. RECENT FINDINGS: Currently, two RPLND series have been published as a complete report, while data from other series have only been published as congress abstracts. In series without adjuvant chemotherapy, recurrence rates ranged from 13% to 30% after follow-ups of 21-32 months. In those receiving RPLND and adjuvant chemotherapy, the recurrence rate was 6% after a mean follow-up of 51 months. Across all trials, recurrent disease was treated with systemic chemotherapy (22/25), surgery (2/25), and radiotherapy (1/25). The rate of pN0 disease after RPLND varied between 4% and 19%. Postoperative complications were reported in 2-12%, while antegrade ejaculation was maintained in 88-95% of patients. Median length of stay ranged from 1 to 6 days. SUMMARY: In men with clinical stage II seminoma, RPLND is a safe and promising treatment option. Further research is needed to determine the risk of relapse and to personalize treatment options based on patient-specific risk factors.

Extrinsic apoptosis and senescence involved in growth kinetics of seminoma to cisplatin.

Seminoma is the most common type of testicular germ cell tumour and is highly sensitive to cisplatin therapy, which has not been fully elucidated. In this study, we comprehensively monitored dynamic changes of TCam-2 cells after cisplatin treatment. At an early stage, we found that both low and high concentrations of cisplatin induced the S-phase arrest in TCam-2 cells. By contrast, the G0G1 arrest was caused by cisplatin in teratoma NTERA-2 cells. Afterwards, high concentrations of cisplatin promoted the extrinsic apoptosis and high expressions of related genes (Fas/FasL-caspase-8/-3) in TCam-2 cells. However, when decreasing the cisplatin, the apoptotic cells were significantly reduced, and accompanied by cells showing senescence-like morphology, positive SA-ß-gal staining and up-regulation of senescence-related genes (p53, p21 and p16). Furthermore, the cell cycle analysis revealed that most of the senescent TCam-2 cells were irreversibly arrested in the G2M phase. G2M arrest was also observed in NTERA-2 cells treated with a low concentration of cisplatin, while no senescence-related phenotype was discovered. In addition, we detected the γ-H2AX, a DNA damage marker protein, and reactive oxygen species (ROS) and found both of which were elevated with the increase of cisplatin in TCam-2 cells. In conclusion, the extrinsic apoptosis and senescence are involved in the growth kinetics of TCam-2 cells to cisplatin, which provide some implications for studies on cisplatin and seminoma.

Single-dose carboplatin followed by involved-node radiotherapy for stage IIA and stage IIB seminoma (SAKK 01/10): a single-arm, multicentre, phase 2 trial.

BACKGROUND: Standard treatment options for patients with stage IIA or stage IIB seminoma include either para-aortic and pelvic radiotherapy or three to four cycles of cisplatin-based combination chemotherapy. These options result in 3-year progression free survival rates of at least 90%, but bear risks for acute and late toxic effects, including secondary malignancies. We tested a novel approach combining de-escalated chemotherapy with de-escalated involved node radiotherapy, with the aim of reducing toxicity while preserving efficacy. METHODS: In the single-arm, multicentre, phase 2 SAKK 01/10 trial, patients with stage IIA or IIB classic seminoma (either at primary diagnosis or at relapse during active surveillance for stage I) were enrolled at ten centres of the Swiss Group for Clinical Cancer Research and ten centres of the German Testicular Cancer Study Group. WHO performance status 0-2, age 18 years or older, and adequate bone marrow and kidney function were required for eligibility. Treatment comprised one cycle of carboplatin (area under the curve 7) followed by involved-node radiotherapy (30 Gy in 15 fractions for stage IIA disease and 36 Gy in 18 fractions for stage IIB disease). The primary endpoint was 3-year progression-free survival. Efficacy analyses were done on the full analysis set, which comprised all patients who signed the informed consent, were registered in the trial, initiated trial treatment, and met all medically relevant inclusion or exclusion criteria. Safety was assessed in all patients who were treated at least once with one of the trial treatments. The study is ongoing but no longer recruiting, and is registered with Clinicaltrials.gov, NCT01593241. FINDINGS: Between Oct 18, 2012, and June 22, 2018, 120 patients were registered in the study. 116 patients were eligible and started treatment according to the study protocol (46 patients with stage IIA disease and 70 with stage IIB disease). After a median follow-up of 4·5 years (IQR 3·9-6·0), 3-year progression-free survival was 93·7% (90% CI 88·5-96·6). With a target progression-free survival of 95% at 3 years, the primary endpoint was not met. Acute treatment-related adverse events of any grade were noted in 58 (48%) of 116 patients, and grade 3 or 4 treatment-related adverse events occurred in the form of neutropenia in five (4%) patients, thrombocytopenia in three (3%) patients, and vomiting in one (1%) patient. No treatment-related deaths and no late treatment-related adverse events were reported. Serious adverse events were reported in five (4%) of 116 patients (one transient creatinine increase and four second primary tumours). INTERPRETATION: Despite the fact that the primary endpoint was not met, we observed favourable 3-year progression-free survival with single-dose carboplatin area under the curve 7 and involved-node radiotherapy, with minimal toxic effects. Our findings might warrant discussion with patients about the SAKK 01/10 regimen as an alternative to standard-of-care treatment, but more research on this strategy is needed. FUNDING: Swiss State Secretariat for Education, Research and Innovation and Rising Tide Foundation for Clinical Cancer Research.

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.

Therapy of clinical stage IIA and IIB seminoma: a systematic review.

PURPOSE: The optimal treatment for clinical stage (CS) IIA/IIB seminomas is still controversial. We evaluated current treatment options. METHODS: A systematic review was performed. Only randomized clinical trials and comparative studies published from January 2010 until February 2021 were included. Search items included: seminoma, CS IIA, CS IIB and therapy. Outcome parameters were relapse rate (RR), relapse-free (RFS), overall and cancer-specific survival (OS, CSS). Additionally, acute and long-term side effects including secondary malignancies (SMs) were analyzed. RESULTS: Seven comparative studies (one prospective and six retrospective) were identified with a total of 5049 patients (CS IIA: 2840, CS IIB: 2209). The applied treatment modalities were radiotherapy (RT) (n = 3049; CS IIA: 1888, CSIIB: 1006, unknown: 155) and chemotherapy (CT) or no RT (n = 2000; CS IIA: 797, CS IIB: 1074, unknown: 129). In CS IIA, RRs ranged from 0% to 4.8% for RT and 0% for CT. Concerning CS IIB RRs of 9.5%-21.1% for RT and of 0%-14.2% for CT have been reported. 5-year OS ranged from 90 to 100%. Only two studies reported on treatment-related toxicities. CONCLUSIONS: RT and CT are the most commonly applied treatments in CS IIA/B seminoma. In CS IIA seminomas, RRs after RT and CT are similar. However, in CS IIB, CT seems to be more effective. Survival rates of CS IIA/B seminomas are excellent. Consequently, long-term toxicities and SMs are important survivorship issues. Alternative treatment approaches, e.g., retroperitoneal lymph node dissection (RPLND) or dose-reduced sequential CT/RT are currently under prospective investigation.

How to classify, diagnose, treat and follow-up extragonadal germ cell tumors? A systematic review of available evidence.

PURPOSE: To present the current evidence and the development of studies in recent years on the management of extragonadal germ cell tumors (EGCT). METHODS: A systematic literature search was conducted in Medline and the Cochrane Library. Studies within the search period (January 2010 to February 2021) that addressed the classification, diagnosis, prognosis, treatment, and follow-up of extragonadal tumors were included. Risk of bias was assessed and relevant data were extracted in evidence tables. RESULTS: The systematic search identified nine studies. Germ cell tumors (GCT) arise predominantly from within the testis, but about 5% of the tumors are primarily located extragonadal. EGCT are localized primarily mediastinal or retroperitoneal in the midline of the body. EGCT patients are classified according to the IGCCCG classification. Consecutively, all mediastinal non-seminomatous EGCT patients belong to the "poor prognosis" group. In contrast mediastinal seminoma and both retroperitoneal seminoma and non-seminoma patients seem to have a similar prognosis as patients with gonadal GCTs and metastasis at theses respective sites. The standard chemotherapy regimen for patients with a EGCT consists of 3-4 cycles (good vs intermediate prognosis) of bleomycin, etoposid, cisplatin (BEP); however, due to their very poor prognosis patients with non-seminomatous mediastinal GCT should receive a dose-intensified or high-dose chemotherapy approach upfront on an individual basis and should thus be referred to expert centers Ifosfamide may be exchanged for bleomycin in cases of additional pulmonary metastasis due to subsequently planned resections. In general patients with non-seminomatous EGCT, residual tumor resection (RTR) should be performed after chemotherapy. CONCLUSION: In general, non-seminomatous EGCT have a poorer prognosis compared to testicular GCT, while seminomatous EGGCT seem to have a similar prognosis to patients with metastatic testicular seminoma. The current insights on EGCT are limited, since all data are mainly based on case series and studies with small patient numbers and non-comparative studies. In general, systemic treatment should be performed like in testicular metastatic GCTs but upfront dose intensification of chemotherapy should be considered for mediastinal non-seminoma patients. Thus, EGCT should be referred to interdisciplinary centers with utmost experience in the treatment of germ cell tumors.

Paraneoplastic Demyelinating Inflammatory Neuropathy Revealing Metastatic Seminoma: A Case Report.

Paraneoplastic neurological syndrome (PNS) is uncommon and not well known. PNS can reveal cancer, but its role in seminomas has not been described explicitly. We report the case of a 36-year-old man with unremarkable medical history and no comorbidities who was diagnosed with a retroperitoneal metastatic seminoma. The patient's general condition deteriorated, and he developed progressive neurological palsy without other clinical anomalies. Electromyography revealed demyelinating, non-lengthy neuropathy. Guillain-Barré syndrome was initially suspected. However, a positron emission tomography scan revealed a retroperitoneal mass, and blood markers revealed increased human chorionic gonadotropin. The patient was diagnosed with PNS, and a computed tomography-guided biopsy revealed a metastatic seminoma without a primary tumor. No circulating neural antibodies were detected. Human polyvalent immunoglobulin was simultaneously administered with chemotherapy. After three cycles of a cisplatin-etoposide-bleomycin, a complete biological and metabolic response rate was observed, and his neurological symptoms rapidly improved. Four years later, the patient responded completely, without any neurological complaints. Paraneoplastic demyelinating inflammatory neuropathy can lead to advanced seminoma diagnosis. Prompt management of seminomas with cisplatin-based regimens provides the best chance of cure for both advanced seminoma and paraneoplastic syndrome.

Exosomal miR-193b-3p Contributes to Cisplatin Sensitivity in Seminoma by Targeting ZBTB7A.

A previous study confirmed that miRNAs play an important role in the chemosensitivity of seminoma. Increasing evidence reveals that exosomes participate in the regulation of cisplatin resistance by carrying miRNAs. In this study, we further explored whether exosomes regulated the chemosensitivity of seminoma TCam-2 cells to cisplatin. Initially, cisplatin-resistant TCam-2 cells were induced. Our results revealed that exosomes from cisplatin-resistant TCam-2 cells (rExos) could affect the viability of TCam-2 cells in the context of cisplatin treatment through regulation of both cell apoptosis and the cell cycle. Meanwhile, the levels of γ-H2AX were negatively modulated by rExos, which indicated that rExos could decrease the DNA damage from cisplatin. Furthermore, miR-193b-3p was enriched in rExos, and exosomal miR-193b-3p enhanced the proliferative ability of TCam-2 cells under cisplatin treatment. Mechanistically, exosomal miR-193b-3p targets ZBTB7A, which further decreases apoptosis and promotes cell cycle progression. Taken together, these findings indicate that exosomal miR-193b-3p regulates the chemosensitivity of TCam-2 cells to cisplatin through ZBTB7A signaling and could be a promising drug target for patients with chemoresistant seminoma.

Surveillance versus Adjuvant Treatment with Chemotherapy or Radiotherapy for Stage I Seminoma: A Systematic Review and Meta-Analysis According to EAU COVID-19 Recommendations.

Background and Objectives: During the coronavirus disease 2019 (COVID-19) outbreak, the European Association of Urology (EAU) Guidelines Office Rapid Reaction Group (GORRG) recommended that patients with clinical stage I (CSI) seminoma be offered active surveillance (AS). This meta-analysis aimed to evaluate the efficacy of AS versus adjuvant treatment with chemotherapy or radiotherapy for improving the overall survival (OS) of CSI seminoma patients. Materials and Methods: A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed/Medline, EMBASE, and Cochrane Library databases were searched. The primary outcome was 5-year OS, and the secondary outcome was the 5-year relapse-free survival (RFS). The outcomes were analyzed as odds ratios (ORs) and 95% confidence intervals (CIs). Results: A total of 14 studies were included. Overall, the quality scores were relatively high, and little publication bias was noted. In terms of the 5-year OS, 7 studies were analyzed; there was no significant difference between AS and adjuvant treatment (OR, 0.99; 95% CI, 0.41−2.39; p = 0.97). In terms of 5-year RFS, 12 studies were analyzed. Adjuvant treatment reduced the risk of 5-year recurrence by 85% compared with AS (OR, 0.15; 95% CI, 0.08−0.26; p < 0.001). Conclusions: In terms of the OS in CSI seminoma patients, no intergroup difference was noted, so it is reasonable to offer AS, as recommended by the EAU GORRG until the end of the COVID-19 pandemic. However, since there is a large intergroup difference in the recurrence rate, further research on the long-term (>5 years) outcomes is warranted.

Complete testicular remission after chemotherapy in a patient with advanced seminoma: is the testicle a real 'sanctuary'? A case report and review of the literature.

Testicular cancer is relatively uncommon, but at the same time, it is the most common solid tumor in men between the ages of 20 and 34 years. Seminoma represents the most frequently encountered germ cell tumors. Because orchiectomy is usually performed before chemotherapy, little is known about the effect of systemic chemotherapy on primary testicular tumors. Furthermore, the testis has always been considered a sanctuary site, an immune-privileged site in which inadequate exposure of the tumor to chemotherapy may occur. We report the case of a young patient with advanced seminoma with a complete testicular response after four cycles of cisplatin-based chemotherapy. Then, we performed a systematic review of the literature reporting the studies published to date on the topic.

Outcomes of post-chemotherapy robot-assisted retroperitoneal lymph node dissection in testicular cancer: multi-institutional study.

OBJECTIVE: To evaluate the perioperative and oncological outcomes after post-chemotherapy robot-assisted retroperitoneal lymph node dissection (PC-RARPLND). MATERIALS AND METHODS: We retrospectively reported the perioperative and oncological outcomes of all the patients with testicular cancer who underwent PC-RARPLND at three tertiary teaching centers. Descriptive statistical measures were used to report demographic, clinical, intraoperative, postoperative and oncological outcomes. RESULTS: There were 43 consecutive patients who underwent PC-RARPLND at the participating institutions. Mean patient age was 29.2 years (± 8.2), BMI was 26.6 kg/m2 (± 6.2). The mean size of retroperitoneal mass was 4.1 cm (± 3.5). Full bilateral template dissection was performed in 38 (88.3%) patients. Nerve sparing was attempted in 19 (44.1%) patients. Mean operative time was 374 min (± 132) and estimated blood loss was 292 ml (± 445.6). The mean postoperative LOS was 2.8 days (± 5.9). There was a total of 12 complications in 10 patients (Clavien grade I = 5, II = 3, III = 3 and IV = 1). Postoperative pathology demonstrated 24 patients (55%) with necrosis/fibrosis, 16 (37%) with teratoma and 3 (7%) with viable tumor. Mean lymph node (LN) yield was 26.5 LNs (SD ± 16.1). Patients were followed for a mean of 30.7 months (± 24.7). No deaths were documented during follow-up and 2 pulmonary recurrences were identified. Antegrade ejaculation was preserved in 70.6% of patient who underwent nerve sparing. Limitations included retrospective nature and limited follow up. CONCLUSION: PC-RAPLND is safe and technically reproducible. It provides improved morbidity and less convalescence.

Stage I testicular seminoma risk-adapted therapeutic management.

Following orchiectomy, patients with clinical stage I (CSI) testicular seminoma may be managed by active surveillance (S) or adjuvant treatment (radiotherapy or chemotherapy). In view of the published data on long-term toxicity, especially second malignant neoplasms (SMNs), adjuvant radiotherapy (ART) is currently no longer recommended as an adjuvant therapy option for these patients. The purpose of our recent study was to compare the impact of two selected treatment approaches - S versus adjuvant chemotherapy (ACT) on the survival of patients with CSI testicular seminoma. This cross-sectional study analyzed a total of 139 patients collected at a single center between 10/2011-5/2020, with CSI testicular seminoma, stratified into two groups according to risk-adapted therapeutic approaches. In the S group (low-risk - without rete testis invasion - RTI, primary tumor size <4 cm), consisting of 77 patients, who underwent S, relapse occurred in 10 (13.0%) patients after a mean follow-up of 14.3 months. In the ACT group (high-risk - RTI and/or primary tumor size >4 cm), consisting of 62 patients, who were treated with ACT, relapse occurred in 5 (8.1%) patients after a mean follow-up of 11.6 months. Overall survival of patients in both groups was 100% with a mean follow-up of 43.9 months. A statistically significant difference in progression-free survival (PFS) between these two groups was not found. Based on our findings, ACT seems to be an adequate treatment for patients with a high risk of relapse, as well as S for those with a low risk of relapse. Despite its excellent prognosis, optimal management of CSI testicular seminoma remains controversial, with variations in expert opinion and international guidelines.

Management of residual disease after chemotherapy in germ cell tumors.

PURPOSE OF REVIEW: Although testicular cancer remains a highly curable malignancy, challenges and uncertainty still remain in certain aspects of management. Residual disease after chemotherapy in patients with germ cell tumors (GCT) remains one of these challenges. We aim to highlight the recent literature on the management of residual disease after chemotherapy in GCT and the emerging innovations that may provide further guidance into this area. RECENT FINDINGS: A subset of patients with GCT will have residual disease after chemotherapy, and management of these patients involves highly skilled multidisciplinary experts including medical oncologists, surgeons, radiologists, and pathologists. Management options depend on histologic subtype, either seminoma or nonseminoma, and involve size criteria, possible further imaging modalities, and tumor markers. Even with these tools at highly specialized expert centers, uncertainty in management remains, and recent literature has explored the use of newer biomarkers to aid in these cases. SUMMARY: Postchemotherapy residual masses in GCT can prove to be complicated cases to manage. Balancing survival with quality of life outcomes is important and requires a multidisciplinary team experienced in treating GCT.

Leptin Receptor as a Potential Target to Inhibit Human Testicular Seminoma Growth.

Although in past decades the adipokine leptin and its own receptor have been considered as significant cancer biomarkers, their potential involvement in human testicular seminoma growth and progression remains unexplored. Here, we showed that the expression of leptin and its receptor was significantly higher in human testicular seminoma compared with normal adult testis. Human seminoma cell line TCam-2 also expressed leptin along with the long and short isoforms of leptin receptor, and in response to leptin treatment showed enhanced activation of its downstream effectors. In line with these results, leptin stimulation significantly increased the proliferation and migration of TCam-2 cells. Treatment of TCam-2 cells with the peptide Leu-Asp-Phe-Ile (LDFI), a full leptin-receptor antagonist, completely reversed the leptin-mediated effects on cell growth and motility as well as reduced the expression of several leptin-induced target genes. More importantly, the in vivo xenograft experiments showed that LDFI treatment markedly decreased seminoma tumor growth. Interestingly, LDFI-treated tumors showed reduced levels of the proliferation marker Ki-67 as well as decreased expression of leptin-regulated genes. Taken together, these data identify, for the first time, leptin as a key factor able to affect testicular seminoma behavior, highlighting leptin receptor as a potential target for novel potential treatments in this type of cancer.

Evidence that activin A directly modulates early human male germline differentiation status.

Disrupted fetal germline development underpins testicular germ cell neoplasia, which is increasing worldwide. The complex signaling milieu during normal testis development includes TGFß superfamily ligands; this study tests the hypothesis that, activin A, a TGFß superfamily member, can influence gonocyte development. The human seminoma-derived cell line, TCam-2, a model of fetal gonocytes, was cultured with activin A (1.25-25 ng/mL) for 48 h, or with 5 ng/mL activin A for short- (6, 24, and 48 h) and long-term (13 days) exposures, and downstream targets measured by qRT-PCR. Transcripts that exhibited significant dose-dependent responses to activin A included the early germ cell markers KIT, NODAL, and CRIPTO (NODALl co-receptor and activin inhibitor) which all increased and the differentiation marker DNMT3L which decreased. After 48 h, KIT, NODAL, and CRIPTO levels were significantly higher, while the differentiation marker NANOS2 was significantly lower. Interestingly, activin A exposure also significantly reduced both transcript and protein levels of the PIWI/piRNA pathway component DNMT3L. Because TCam-2 cells produce the activin inhibitor CRIPTO, CRIPTO was reduced using siRNA prior to activin A exposure. This selectively increased KIT in response to activin A. Other ligands present in the fetal testis (BMP4, FGF9, TGFß1, and TGFß2) induced distinct effects on germline marker expression. This study showed that activin A can directly modulate germline markers in this human gonocyte-like cell, promoting a less-differentiated phenotype. Additional findings indicate evidence of signaling crosstalk between activin A and NODAL, leading to target-specific effects on gonocyte differentiation.

[A Case of Primary Mediastinal Seminoma Showing Local Increase in Residual Tumor after Chemotherapy].

A 19-year-old man with abnormal findings on his chest X ray was referred to our hospital. A chest computed tomography scan revealed a 57 mm mass in the anterior mediastinum, and percutaneous needle biopsy was performed. Histopathological diagnosis was pure seminoma. Since the serum alphafetoprotein (AFP) level was normal and no abnormal findings were noted in the testis, the patient was diagnosed with mediastinal seminoma [International Germ Cell Consensus Classification (IGCCC) goodrisk group]. After three cycles of chemotherapy with bleomycin/etoposide/cisplatin [BEP], the tumor decreased in size to 32 mm, and a fluorodeoxyglucose-positron emission tomography scan indicated negative tumor findings. After four months, the residual tumor increased in size to 40 mm without any increase in the tumor marker levels. Surgical resection was performed, and the histopathological finding was only mature teratoma. Six months after the operation, there has been no recurrence.

Testis developmental related gene 1 regulates the chemosensitivity of seminoma TCam-2 cells to cisplatin via autophagy.

We previously identified testis developmental related gene 1 (TDRG1), a gene implicated in proliferation of TCam-2 seminoma cells. Recent evidence has revealed that autophagy influences the chemosensitivity of cancer cells to chemotherapy. However, whether TDRG1 protein regulates autophagy in seminoma cells and influences their sensitivity to cis-dichlorodiammine platinum (CDDP) remains unknown. In this study, we used TCam-2 cells and male athymic BALB/c nude mice with xenografts of TCam-2 cells to investigate autophagy, cell viability, apoptosis and the p110ß/Rab5/Vps34 (PI3-kinase Class III) pathway under the conditions of TDRG1 overexpression or knockdown and with or without CDDP treatment. We found that TDRG1 upregulation promoted autophagy in both TCam-2 cells and seminoma xenografts via p110ß/Rab5/Vps34 activation. Inhibition of autophagy reduced cell viability and promoted apoptosis during CDDP treatment of TCam-2 cells. Similarly, TDRG1 knockdown inhibited autophagy, reduced cell viability and promoted apoptosis during CDDP treatment of TCam-2 cells. TDRG1 knockdown inhibited tumour growth and promoted apoptosis in TCam-2 cell xenografts, whereas TDRG1 overexpression had the opposite effect. According to these results, we propose that high expression of TDRG1 promotes autophagy through the p110ß/Rab5/Vps34 pathway in TCam-2 cells. TDRG1 overexpression promotes autophagy and leads to CDDP resistance, whereas TDRG1 knockdown inhibits autophagy and promotes chemosensitivity to CDDP both in vivo and in vitro. This study has uncovered a novel role of TDRG1 in reducing chemoresistance during CDDP treatment and provides potential therapeutic strategies for the treatment of human seminoma.