MCL1 and Familial prostate cancer: In order contextualize the effect of MCL1 on G1/S cellular transition within the P18 regulated CDK4/6-RB1 pathway, we assessed the impact of that MCL1 overexpression has on DU-145 cells, a P18 expressing but RB1-mutant (non-functional protein through exon 21 deletion) prostate cancer cell line31.