We hypothesized that the tumor-promoting effects of SUMO1P3 in bladder cancer may be partially mediated by miR-320a negative regulation, as occurs in breast cancer (11), and that the molecular mechanism consists of sequestering miRNA by sponging through miRNA binding sites, already identified in the SUMO1P3 sequence (11, 21). This evidence concerns the gene SUMO1P3 and breast carcinoma.