The CDKN2A locus, located on human chromosome 9p21, is one of the most common genetic losses in human cancer.118,119 TCGA profiling of 178 LSCC samples revealed that CDKN2A is inactivated in 72% cases of LSCC.4 The CDKN2A locus encodes two alternatively spliced proteins, p16INK4a (p16) and p14ARF (p14), which function as cell-cycle inhibitors. Here, CDKN2A is linked to cancer.