TACSTD2 and yolk sac tumor: In patients with cisplatin-resistant GCT metastases after chemotherapy, TROP2 mRNA levels are significantly higher in choriocarcinoma metastases [CC-MET(-R)] and teratoma metastases [TER-MET(-R)] compared to yolk sac tumor metastases [YST-MET(-R)] (Kruskal–Wallis test, p < 0.01), while there is no statistically significant difference in mRNA expression among choriocarcinoma, teratoma, and embryonal carcinoma metastases [EC-MET(-R)] (Fig. 1A).