The largest hormonal cluster #2 (42 to 50% of samples) included predominantly seminomas and was hallmarked by high expression of the testosterone—DHT converting enzyme SRD5A3. Hormonal cluster #3 comprised of NSGCT (8.3 to 18% of samples, mixed histology, embryonal carcinoma, yolk sac tumors) with high expression of CGA gonadotropin subunit as well as genes involved in estrogen and estradiol synthesis and inter-conversion (CYP19A1, HSD17B12, HSD17B1), and SHBG involved in hormone binding and transport. The gene discussed is HSD17B1; the disease is yolk sac tumor.