CDKN2A and neoplasm: There is also growing literature on the molecular and clinical impact of 9p21-loss, and the recognition that MTAP-loss is synonymous to 9p21-loss in GI cancers facilitates a better understanding of evolving literature.10,20,34 In GEAC and PDAC, however, there is a proportion of MTAP-intact tumors with CDKN2A and CDKN2B alterations, making confirmation of MTAP-loss in these tumor types important.