CDKN2A and cancer: CDKN2A inactivation provides a survival advantage to cancer cells, with the most common genomic alteration causing this event being the homozygous (biallelic) deletion of CDKN2A. In greater than 90% of cancer tissues harboring CDKN2A deletion, the adjacent CDKN2B gene on chromosome 9p, encoding the p15INK4B cyclin dependent kinase inhibitor, is also deleted [3, 4].