CDKN1A and malignant colon neoplasm: P21Cip1/Waf1 is a very important cyclin-CDK inhibitor that negatively mediates G1 phase progression [60]; some researches have reported that miR-30a specifically targets HP1γ, which inhibits colon cancer growth by upregulating P21Cip1/Waf1 expression, resulting in cell cycle arrest at G0/G1 in colorectal cancer cells.