PARP1 and Familial prostate cancer: Interestingly, MALAT1 depletion in prostate cancer cells harboring mutations in BRCA1/2, namely 22RV1 and LNCaP showed a remarkable increase in drug sensitivity, while prostate cancer cells with no predicted biallelic mutations in canonical HR genes, that is, DU145 and PC3 cells (58), exhibited a modest increase in PARP sensitivity upon MALAT1 knockdown (Fig. 6A).