SRM and urinary bladder carcinoma: Previous studies have shown that c-MYC directly regulates ornithine decarboxylase 1 (ODC1), spermidine synthase (SRM), and glutaminase (GLS), the upstream genes of polyamine metabolism59,60, its synergistic relationship with polyamine metabolism has been demonstrated in bladder cancer, neuroblastoma, and colorectal cancer61–63.