Figure 3: Expression of trophoblast (CDX2), cell fate determining (NOTCH1), and core “stemness-” associated (OCT4, NANOG, and SOX2) stem cell transcription factors in HTR8/SVneo cells. HTR8/SVneo cells express CDX2, NOTCH1, NANOG, and SOX2 ((a), (e), (i), and (q)). OCT4 signaling is lost after blocking the samples with human serum ((m) versus (n)). Human serum is needed to further block exceptional, unspecific binding on trophoblastic cells that cannot be eliminated via conventional blocking measures. Immunofluorescent staining seems less specific with or without blockage with human serum ((c), (d), (g), (h), (k), (l), (o), (p), (s), and (t)).