MTAP and cancer: From a pan-cancer study of data from The Cancer Genome Atlas, homozygous deletion of MTAP was described in 9.3% of cancers, with loss of heterozygosity at 9p21 due to hemizygous deletion of MTAP observed in another 27.8% of cancers.10 Despite the relatively high prevalence of 9p21/MTAP-loss, investigation in the field has been limited by the challenges associated with targeting loss-of-function mutations.