Animal models of TGCT and correlation to human histologic subtypes.TGCTs appear to arise from embryonic germ cells (EGC) in infants and young children (“type I”) or in adolescents and young adults (“type II”) [4]. (For clarity, the presumed carcinoma in situ precursor cell for type II tumours is omitted). These are further sub-divided by histologic subtype: yolk sac tumour (YST), teratoma (Ter), seminoma, choriocarcinoma (CC), embryonal carcinoma (EC). Current animal models of TGCT correlate to type I teratomas (129/Sv mice) and type II seminomas (bmpr1bb or lrrc50 fish). Important genetic aberrations in human tumours are listed below. Mouse teratoma photo courtesy of Dr. David Zarkower. A big catch for germ cell tumour research. Chen KS, Amatruda JF - PLoS genetics (2013). Not Altered. CC.