ESR1 and breast cancer: Overall, the functional enrichment significance scores for ER-negative and ER-positive IBC networks showed moderate correlation with each other (Spearman Rho = 0.23), but little correlation with the epithelial-stromal co-expression network functional enrichment scores in normal breast (Spearman Rho = −0.06 and −0.08 with ER-positive IBC and ER-negative IBC, respectively), supporting significant functional network rewiring in breast cancer (Fig. 4).