MTAP and renal cell carcinoma: Cancer cells with MTAP loss exhibit a significant accumulation of MTA, which is not only a metabolic intermediate in the conversion of putrescine to spermidine and of spermidine to spermine30 but also a pharmacological agent used to inhibit arginine methylation.16,17,25,31 To determine the effect of MTAP expression on arginine methylation in RCC cells, we measured levels of monomethylarginine (mMA), asymmetric dimethylarginine (aDMA) and symmetric dimethylarginine (sDMA) in both MTAP-expressing (WT) and MTAP KO cells.