CDKN1A and breast carcinoma: To further evaluate the effects of YB-1 knockout on the differentiation of cancer stem cells, the expression levels of differentiation genes in breast cancer stem cells (CDH1, DSP, and ZO-1) [30–32] and in melanoma stem cells (mda-5, mda-6, mda-7, and AP-1) [33–36] were examined.