The CDK inhibitor and tumor suppressor p16INK4a inhibits CDKs 4 and 6; however, its loss, via deletion or promoter methylation, may allow unchecked cell cycle progression and promote cancer progression in several tumor types, such as breast cancer, esophageal cancer, head and neck cancer, mesothelioma, non-small cell lung cancer, and pancreatic cancer [1,2,3,9]. Here, CDKN2A is linked to breast cancer.