Late relapsing germ cell tumors with elevated tumor markers

A case of testicular cancer with retroperitoneal lymph node metastasis of teratoma with somatic-type malignancy 18 years after initial treatment

Introduction

In testicular cancer, late relapse of teratoma with somatic-type malignancy is rare and associated with a poor survival. A case of retroperitoneal lymph node metastasis of teratoma with somatic-type malignancy 18 years after initial treatment for testicular cancer is reported.

Case presentation

A 46-year-old man had a 15-mm-sized mass in the para-aortic region 18 years after initial treatment for testicular cancer, without elevated serum alfa-fetoprotein or human chorionic gonadotropin levels. Laparoscopic retroperitoneal lymph node dissection was performed. The pathological findings showed teratoma with somatic-type malignancy, and the findings of primary testicular cancer reported a yolk sac tumor, not teratoma.

Conclusion

Late relapse of teratoma with somatic-type malignancy was resected by laparoscopic retroperitoneal lymph node dissection. Therefore, long-term follow-up should be considered if patients with small retroperitoneal masses did not undergo retroperitoneal lymph node dissection, and early detection and surgical resection for relapse might be effective.

Targeting CLDN6 in germ cell tumors by an antibody-drug-conjugate and studying therapy resistance of yolk-sac tumors to identify and screen specific therapeutic options

BACKGROUND

Being the standard-of-care for four decades, cisplatin-based chemotherapy is highly efficient in treating germ cell tumors (GCT). However, often refractory patients present with a remaining (resistant) yolk-sac tumor (YST(-R)) component, resulting in poor prognosis due to lack of novel treatment options besides chemotherapy and surgery. The aim of this study was to identify novel targets for the treatment of YST by deciphering the molecular mechanisms of therapy resistance. Additionally, we screened the cytotoxic efficacy of a novel antibody-drug-conjugate targeting CLDN6 (CLDN6-ADC), as well as pharmacological inhibitors to target specifically YST.

METHODS

Protein and mRNA levels of putative targets were measured by flow cytometry, immunohistochemical stainings, mass spectrometry of formalin-fixed paraffin-embedded tissues, phospho-kinase arrays, or qRT-PCR. Cell viability, apoptosis and cell cycle assays of GCT and non-cancerous cells were performed using XTT cell viability assays or Annexin V / propidium iodide flow cytometry, respectively. Druggable genomic alterations of YST(-R) tissues were identified by the TrueSight Oncology 500 assay.

RESULTS

We demonstrated that treatment with a CLDN6-ADC enhanced apoptosis induction specifically in CLDN6⁺ GCT cells in comparison with non-cancerous controls. In a cell line-dependent manner, either an accumulation in the G2 / M cell cycle phase or a mitotic catastrophe was observed. Based on mutational and proteome profiling, this study identified drugs targeting the FGF, VGF, PDGF, mTOR, CHEK1, AURKA, or PARP signaling pathways as promising approaches to target YST. Further, we identified factors relevant for MAPK signaling, translational initiation and RNA binding, extracellular matrix-related processes as well as oxidative stress and immune response to be involved in therapy resistance.

CONCLUSIONS

In summary, this study offers a novel CLDN6-ADC to target GCT. Additionally, this study presents novel pharmacological inhibitors blocking FGF, VGF, PDGF, mTOR, CHEK1, AURKA, or PARP signaling for the treatment of (refractory) YST patients. Finally, this study shed light on the mechanisms of therapy resistance in YST.

Reprint of: somatic-type malignancies in testicular germ cell tumors

The development of somatic-type malignancy (SM) in testicular germ cell tumor represents a major challenge in the diagnosis and treatment of testicular cancer. Most SMs are derived from teratoma, and the remainder is associated with yolk sac tumor. They occur more frequently in metastases than in primary testicular tumors. SMs demonstrate a variety of histologic types, including sarcoma, carcinoma, embryonic-type neuroectodermal tumor, nephroblastoma-like tumor, and hematologic malignancy. Sarcoma, particularly rhabdomyosarcoma, accounts for the majority of SMs in the primary testicular tumors, whereas carcinoma, particularly adenocarcinoma, is the most common SM in metastases. Although SMs derived from testicular germ cell tumors mimic their histologic counterparts in other organs with overlapping immunohistochemical profiles, isochromosome 12p is present in most SMs, which can be useful in the differential diagnosis. The presence of SM in the primary testicular tumor may not worsen the outcome, but the development of SM in metastasis is associated with a poor prognosis. Furthermore, somatic-type carcinoma is likely associated with a worse prognosis than somatic-type sarcoma. Although SMs respond poorly to the cisplatin-based chemotherapy, timely surgical resection is an effective treatment for most patients.

Pathologic Findings and Clinical Outcomes in Patients who Required Neoadjuvant Chemotherapy Prior to Orchiectomy for Testicular Germ Cell Tumors

Treatment for testicular germ cell tumors (GCT) includes orchiectomy followed potentially by adjuvant chemotherapy. Rarely, patients with testicular GCT have significant metastatic disease, requiring neoadjuvant chemotherapy prior to orchiectomy. We investigated the pathologic findings and clinical outcomes in patients who underwent neoadjuvant chemotherapy prior to orchiectomy for testicular GCT. We identified 45 patients, mean age of 34 years (range 15-66 years). Orchiectomy findings included pure teratoma (n=23), no residual tumor (n=13), mixed GCT (n=5), pure seminoma (n=2), pure yolk sac tumor (YST) (n=1), and pure germ cell neoplasia in situ (GCNIS) (n=1). Cancer specific death occurred in 4/45 (9%) patients. 17/45 (38%) patients experienced disease progression after initial chemotherapy. 11/45 (24%) patients underwent salvage chemotherapy. Retroperitoneal lymph nodes were the most common site of metastases followed by lung. Overall, the most common type of tumor found in metastases was YST (12/45, 27%) and teratoma (11/45, 24%). Of the 23 patients with residual pure teratoma in the testis, 9/23 (39%) had disease recurrence/progression and 3/23 (13%) died. In the metastases of these patients, non-teratoma GCT was found in 17/23 (74%) patients. 9/45 (20%) patients had residual testicular non-teratoma GCT, of which 6/9 (67%) had disease recurrence/progression and 1/9 (11%) died. Patients with no residual testicular disease (ypT0) had a lower risk of disease recurrence/progression (p=0.046) and had no deaths. In patients who have undergone neoadjuvant chemotherapy for testicular GCT, the orchiectomy histology often does not correlate with histology of metastases. No residual testicular disease indicates a better prognosis in these patients.

Somatic-Type Malignancies in Testicular Germ Cell Tumors

The development of somatic-type malignancy (SM) in testicular germ cell tumor represents a major challenge in the diagnosis and treatment of testicular cancer. Most SMs are derived from teratoma, and the remainder is associated with yolk sac tumor. They occur more frequently in metastases than in primary testicular tumors. SMs demonstrate a variety of histologic types, including sarcoma, carcinoma, embryonic-type neuroectodermal tumor, nephroblastoma-like tumor, and hematologic malignancy. Sarcoma, particularly rhabdomyosarcoma, accounts for the majority of SMs in the primary testicular tumors, whereas carcinoma, particularly adenocarcinoma, is the most common SM in metastases. Although SMs derived from testicular germ cell tumors mimic their histologic counterparts in other organs with overlapping immunohistochemical profiles, isochromosome 12p is present in most SMs, which can be useful in the differential diagnosis. The presence of SM in the primary testicular tumor may not worsen the outcome, but the development of SM in metastasis is associated with a poor prognosis. Furthermore, somatic-type carcinoma is likely associated with a worse prognosis than somatic-type sarcoma. Although SMs respond poorly to the cisplatin-based chemotherapy, timely surgical resection is an effective treatment for most patients.