CDKN2C and cancer: Cyclin-dependent kinase inhibitors: The family of cyclin-dependent kinase inhibitor genes, CDKN2A (p16-INK4), CDKN2B (p15-INK4b), CDKN2C (p18-INK4c), and CDKN2D (p19-INK4d), are tumor suppressor genes generally inactivated in human cancers.