[Non-seminomatous germ cell tumours]

TIMEAS, a promising method for the stratification of testicular germ cell tumor patients with distinct immune microenvironment, clinical outcome and sensitivity to frontline therapies

PURPOSE

With the heterogeneous genetic background, prognosis prediction and therapeutic targets for testicular germ cell tumors (TGCTs) are still unclear. We defined the tumor immune microenvironment activation status (TIMEAS).

METHODS

We collected a total of 314 TGCT patients from four cohorts, including a 48-case microarray. A nonnegative matrix factorization algorithm was applied to identify the "immune factor", derived the top 150 weighted genes to divide patients into immune and non-immune classes, and further separated the immune class into activated and exhausted subgroups by nearest template prediction. Tumor mutant burden, gene mutation, and copy number alteration were compared with our recently developed package "MOVICS". A random forest algorithm was performed to establish a prediction model with fewer genes. Immunohistochemistry staining was performed to identify TIMEAS in the microarray.

RESULTS

We constructed the TIMEAS in the TCGA-TGCT cohort and further validated it in the GSE3218 and GSE99420 cohorts. The immune class contained the activated status of T-lymphocytes, B-lymphocytes, and macrophages, while Treg cells and the WNT/TGFβ signature were more activated in the immune-suppressed subgroup. Patients in the immune-exhausted subgroup had the worst prognosis, and 22.9% of patients in the immune-activated subgroup had KRAS mutations, which might stimulate the response of the immune system and lead to a favorable prognosis. The immune-exhausted group benefited more from chemotherapy, while the immune-activated subgroup responded well to anti-PD-1/PD-L1 therapy. FSCN1 was validated as the target of the immune-exhausted microenvironment by immunohistochemistry.

CONCLUSION

TIMEAS classification can separate TGCT patients; patients in the immune-activated subgroup could benefit more from anti-PD-L1 immunotherapy, and those in the immune-exhausted subgroup are more suitable for chemotherapy.

[Germ cell and sex cord-stromal tumors of the testis : WHO classification 2016]

Earlier revisions of the WHO classification of testicular tumors, which was originally published in 1977, contained only minor additions. In the WHO 2016 classification, in contrast, germ cell tumors are split into two major groups based on their distinct pathohistogenesis, i. e., those which derive from an in situ forerunner lesion and those which do not. The latter category includes prepubertal yolk sac tumors and teratomas, as well as spermatocytic seminoma. The classification of yolk sac tumors and teratomas as arising before or after puberty is also of prognostic value. The group of trophoblastic tumors has also been divided into choriocarcinoma and "nonchoriocarcinomatous trophoblastic tumors," which are rare but may also be clinically significant. The changes in the classification of the sex cord-stromal tumors are not particularly important; rare variants without clinical importance of the single well-known tumors have been omitted. A new entity, a kind of "in situ" large cell Sertoli cell neoplasia, has been introduced.

Successful radiotherapy in postoperative recurrence of a primary mediastinal yolk sac tumor: A case report

A woman in her 60s was evaluated for anterior chest pain. Computed tomography (CT) revealed a 50 mm mass with irregular contrast enhancement in the anterior mediastinum. α‐fetoprotein (AFP) level was elevated to 1188 ng/mL. A germ cell tumor was diagnosed, mostly comprising of a yolk sac tumor (YST). Two courses of chemotherapy with cisplatin (CDDP) and etoposide (VP16) were administered and surgical tumor resection was then performed. The final diagnosis was YST. CDDP and VP16 were continued postoperatively; however, because the AFP level increased about six months after surgery, the chemotherapy regimen was altered to bleomycin and CPT‐11. As the AFP again increased and a CT scan revealed tumor re‐enlargement, recurrent YST was diagnosed and radiotherapy was administered. The patient received a total of 60 Gy (2 Gy per fraction). The tumor started to shrink during radiotherapy and AFP levels decreased. By one month post‐radiotherapy, AFP levels had normalized and the tumor had disappeared. As of six years after radiotherapy, the patient remains alive without recurrence. Mediastinal YSTs are rare, and treatment usually includes surgery and preoperative and postoperative chemotherapy with cisplatin‐based regimens. Successful treatment with radiotherapy has occasionally been reported. Our patient showed recurrence of a YST after surgery and chemotherapy, but achieved long‐term survival after radiotherapy. Few patients with YST have undergone radiotherapy, but this approach was successful in our patient. In cases of postoperative recurrent YST resistant to chemotherapy, radiotherapy, together with salvage surgery, may offer a valuable option.