ERBB2 and neoplasm: The association in the ER+/HER2– subgroup was significant in grade 2 tumours (OR per 1 SD 1.43, 95% CI 1.06 to 1.91; p = 0.018; Figs. 1a and 2) and borderline significant in grade 1 tumours (OR per 1 SD 1.83, 95% CI 0.94 to 3.56, p = 0.073).