BRD4 and Familial prostate cancer: Modified anti-STEAP1 antibody-PROTAC conjugates with a BRD4 ligand and a VHL ligand, particularly STEAP1-9d (DAR 5.9) (Figure 12), afforded the highest degradation of the BRD4 protein with a DC50 value of 0.025 nM using PC3-S1 prostate cancer cells [50].