RB1 and prostate cancer: Preclinical studies also demonstrate that several recently developed E1ACR2-deleted mutants such as AdΔCR2, AdΔΔ and AdΔ24, complemented by deregulated pRb/cell cycle pathways, have significantly higher efficacy in combination with various cytotoxic drugs in prostate cancer models [16], [17], [18], [19], [20].