BRCA1 and neoplasm: BRCA1‐deleted tumours can acquire PARPi resistance via loss of 53BP1 (Bouwman et al, 2010; Bunting et al, 2010), REV7 (Xu et al, 2015) or the shieldin complex (Dev et al, 2018; Noordermeer et al, 2018; Tomida et al, 2018).