ERBB2 and breast cancer: Administration of such degrader-antibody conjugates in vivo led to antigen-dependent delivery to acute myeloid leukaemia tumours and induced tumour growth inhibition.202 Using the methylated analogue 113 of MZ1 (Fig. 48b) as payload and trastuzumab as HER2+ cells targeting antibody, degrader-antibody conjugates were developed that induced Brd4 degradation selectively in HER2+ breast cancer cell lines, but not in HER2-cell lines, while the corresponding unconjugated PROTAC could not discriminate between the two cell lines.