ERBB2 and neoplasm: We observed significantly lower correlations between core-based and tumour-based scores for the HER2 subtype compared with other PAM50 intrinsic subtypes with less than 10 cores (Fig. 2A; n = 4: HER2 versus Luminal A p = 0.010; HER2 versus Luminal B p = 0.010; HER2 versus Basal p = 0.011; one-sided paired t-test).