SIRPA and neoplasm: Inhibition of pGlu formation by glutaminyl cyclase isoenzyme (QPCTL), another PTM, affects the CD47–SIRPα interaction and enhances the antitumor effect (24, 25); epidermal growth factor receptor (EGFR) -induced and c-Src-mediated CD47 phosphorylation inhibits TRIM21-dependent ubiquitylation and degradation of CD47, promote tumor immune evasion (48); suggesting that PTMs play an important role in the function and clinical application of CD47.