E2F1 and prostate carcinoma: Specifically, Mao and collaborators found that ectopic expression of miR-449, a miRNA previously reported to be downregulated in prostate cancer tissues compared to patient-matched control tissues [103], enhanced radiation-induced G2/M phase arrest by modulating pRb/E2F1, and this resulted in augmented cell apoptosis and consequent sensitization of prostate cancer cells to IR [102].