We then determined the basis for the unexpected finding that CDK1 inhibited expression of pluripotency genes and cancer stem cell frequency, despite inhibiting KDM5B recruitment to NANOG. A possibility is that KDM5B recruitment and attenuation of H3K4me3 levels on SOX2 and NANOG may not be the critical determinants of KDM5B regulation of the expression of pluripotency genes. Here, SOX2 is linked to cancer.