CDKN2A and melanoma: Specifically, elevated expression of CCND1 is associated with resistance to BRAF inhibition in BRAFV600E melanoma, particularly when CDK4 is also overexpressed (61), and a loss of CDKN2A expression (indicative of elevated CDK4/6 activity) correlates with poor progression free survival in patients treated with dual BRAF and MEK inhibition (62).