BRCA1 and neoplasm: There is evidence for reacquisition of BRCA1 function in tumours that become resistant to PARP inhibitors or platinum, and although BRCA1-∆11q has been shown to drive resistance in overexpression experiments (such as the SUM149 Ex22 + ∆11q cell line used here [35]), it is unclear how tumours would achieve such levels in practice.