The immunohistochemical markers in current use include CD117/KIT, POU5F1 (OCT3/4), PLAP, and CT45 (germinoma); AFP, SALL4 and glypican 3 [yolk sac tumour (YST)]; CD30 (embryonal carcinoma); and HCG (choriocarcinoma). The gene discussed is KIT; the disease is yolk sac tumor.