HPSE and urinary bladder cancer: For example, ciRS-7 suppresses bladder cancer growth by sponging miR-135a, which elevates P21 levels [10]; circular RNA CEP128 promotes bladder cancer cell propagation and migration via sponging mir-145-5p to regulate MAPK (mitogen-activated protein kinase) signaling [11]; and circHIPK3 decreases lung metastasis by sponging miR-558 to suppress heparanase expression [8].