CDKN1A and malignant colon neoplasm: This is consistent with previous data in colon cancer cell lines showing that the number of cells arresting in G1 or G2 can be cell type dependent due to regulation by different checkpoint mechanisms.49 As CDKN1A inhibits both G1 and G2 cell cycle phase progression by binding to and inhibiting CDK2 and CDK1,50 our observation that KLF6-wt mediates G2 arrest in BTSC23 cells is also consistent with the induction of CDKN1A by KLF6.