RB1 and cancer: The retinoblastoma (Rb) gene was the first tumor suppressor to be discovered and as a result, has become a well-established member of cell cycle control [11, 12] First identified in its mutant form in the rare eye tumor, retinoblastoma, the Rb gene is known to be inactivated in nearly all human cancers, signifying its importance in the cell cycle regulation and the maintenance of proliferation [11-13].