Oct-4 (MRQ-10)

Oct-4 is a transcription factor that maintains and regulates pluripotency in embryonic stem and germ cells. Anti-Oct-4 has shown a very high sensitivity and specificity in seminoma/dysgerminoma, embryonal carcinoma, and the germ cell component of gonadoblastoma by nuclear immunostaining. Clear cell carcinoma may enter the differential diagnosis of dysgerminoma as both may grow in nests or tubules, contain clear cells, and have a prominent inflammatory infiltrate (lymphocytes in dysgerminoma and plasma cells in clear cell carcinoma). In one study that looked at anti-Oct-4 staining in clear cell carcinomas, 4 of 14 tumors were found to be focally positive. In another study, 49 endometrioid carcinomas were Oct-4 negative. Rarely dysgerminoma may have a morphologic appearance that overlaps with sex cord-stromal tumors, especially poorly differentiated Sertoli cell tumors. In two studies however, all sex cord-stromal tumors of the testis and granulosa cell tumors of the ovary were Oct-4 negative.