Due to data availability, the protein level positivity of MTAP was used as a surrogate biomarker of 9p21 loss based upon the observations that p16 does not stain well by IHC; TCGA genomics data showed that all of the MTAP-HD bladder cancers were also CDKN2A-HD (Fig. 1d, e); and HD of MTAP led to a marked decrease in its mean gene expression levels in bulk tumor tissues (Fig. 1c) which was further reflected at the protein level. This evidence concerns the gene MTAP and urinary bladder carcinoma.