By binding to E2F1 and Sp1, respectively, BIR2 and BIR3 domains initiate E2F1/Sp1-positive-feedback-loop-dependent transcription of miR-203, inhibiting Src protein translation, which leads to further MMP2-cleaved activation and BC (Bladder Cancer) invasion [13]. This evidence concerns the gene SP1 and urinary bladder carcinoma.