CDKN2A and brain neoplasm: A notable example of a genomic alteration with evolving prognostic value in brain tumors is the loss of the tumor suppressor gene cyclin dependent kinase inhibitor 2A, CDKN2A. Alternative splicing of the CDKN2A locus on chromosome 9p21 results in the translation of two main tumor suppressor proteins: the cyclin dependent kinase inhibitor p16 (aka p16INK4A, p16INK4, CDK4I, MTS1) and, through an alternate open reading frame (ARF), the structurally distinct protein p14 (aka p14ARF) [2, 3].