Likewise, those tumours with the highest immunohistochemical (IHC) staining score for HER2 (score: 3) exhibited the lowest average number of IR events (n = 1825) compared to score 1 (n = 2095) or score 2 (n = 2137) tumours (Additional file 1: Fig. S2C). This evidence concerns the gene ERBB2 and neoplasm.