Integrative data mining analysis was performed to plot the mean values of mRNA expression for ESR1 (ERα gene) and HYAL1 in the whole cohort and in each of the breast cancer subtypes, i.e. luminal A, luminal B, normal-like, basal-like and HER2, as classified by the PAM50 assay [28, 29]. This evidence concerns the gene ERBB2 and breast carcinoma.