POU5F1 and embryonal carcinoma: Given that the positivity of anti-SSEA-3 antibodies was unknown, their positivity for stem cells was confirmed using pluripotent embryonal carcinoma cells (NTERA-2 cl.D1 [NT2/D1] (ATCC®CRL-1973TM), expressed SSEA-334 and octamer-binding transcription factor 3/4 (Oct3/4) (Fig. 3A).