DIRAS3 and neoplasm: miR-221 may also directly inhibit ARHI (a tumor suppressor gene) by binding to its 3′UTR, and thereby contribute to ARHI downregulation in PCa, a mechanism shown to stimulate cell proliferation and invasion as ARHI loss removes its growth-inhibitory and pro-apoptotic functions [51]. miR-145 and miR-331-3p are implicated in the development and progression of aggressive PC by regulating key cell cycle-related hub genes.