CD44 and breast cancer: In qRT-PCR expression studies, the expression of KMT1A in BCSCs (BCMab1+CD44+) and tumorsphere cells was significantly higher than those of BCNSCs (BCMab1–CD44–) and non-tumorsphere cells of T24, BIU87 cell, and primary BC samples (3–5 fold) (#5 and #6) (Figures 4A,B).