BRCA1 and neoplasm: Strikingly, we noticed that in both BRCA1/2-deficient tumour cohorts, H2afx gene expression was significantly reduced in a large fraction of the tumours (11/34 in the KB2P tumours and 12/45 in the KB1P tumours) with only a small overlap with Parg loss or HR restoration (Fig. 1e), which can be explained by the intra-tumoural heterogeneity of the resistance mechanisms11,27.