PRMT5 knockdown in lung cancer (H596, H1048 and H1155), prostate cancer (Du-145) and triple-negative breast cancer (MDA-MB-436) cell lines, all harboring natural RB1 loss-of-function mutations or deletion, resulted in significant growth inhibition, accumulation of cells in G1 phase, and a decrease in cells in S phase (Supplementary Fig. 5), further suggesting the potential applicability of therapeutic targeting of PRMT5 across various types of cancer with RB deficiency. This evidence concerns the gene RB1 and prostate cancer.