ERBB2 and cancer: Finally, we show that 53BP1 protein expression levels was significantly correlated with molecular grouping (63.2% of HR-positive/HER2-negative vs. 47.9% of HER2-positive and 36.2% of TN tumours) and unmethylated BRCA1 promoter (53% of unmethylated vs. 27.8% of methylated cancers).