Large, aggressive tumours (28, 31) and advanced stage cancer (25, 26, 31) were more frequent in the PABC group with overexpression of human epidermal growth factor receptor 2 [HER2] (22, 24–28, 30, 31) and oestrogen receptor negative (27, 28) and progesterone receptor negative status (23, 25–28, 30). This evidence concerns the gene ERBB2 and cancer.