RB1 and Familial prostate cancer: Moreover, the knockdown of RB1, an E2F1 transcriptional activity regulator that is frequently mutated in advanced prostate cancer and suppresses cancer lineage plasticity, metastasis, and androgen deprivation therapy resistance,32 significantly decreased the enrichment of E2F1 within the promoters of CDRs in prostate cancer cells (Fig. 5D).