SOX2 and breast cancer: Similarly, real-time PCR (Supplementary Fig. 1b, c, and d) and immunoblotting analyses (Supplementary Fig. 1e) revealed that the transcription and protein expression levels of TSPAN8, NANOG, SOX2, as well as ALDHA1 were significantly higher in spheres derived from MCF7, HCC1954, and MDA-MB-231 breast cancer cells than those in the corresponding adherent cells.