SOX2 and cancer: Although the transcription factors and stemness genes Oct4 and Sox2[22],[23], stem cell marker of the hair follicle bulge Krt15, the target genes of the Notch signaling pathway HES1[24] and CD44[6] were reported to be high expressed in some cancer stem-like cells, interestingly, in the present study, only Sox2 was significantly overexpressed in SP versus NSP and in SC versus AC in both cell lines; while Oct4, Krt15 and CD44 were upregulated in one or both cell lines SP and/or SC (Fig. 4A and 4B, *P < 0.05, **P < 0.01 ).