Using this approach, our lab has previously demonstrated that KRAS signaling score high-triple negative breast cancer is associated with favorable tumor immune microenvironment and better survival [30], that G2M cell cycle pathway score is a prognostic biomarker of metastasis in ER-positive breast cancer [31], and that E2F pathway score is a predictive biomarker of response to neoadjuvant therapy in ER+/HER2− breast cancer [32]. This evidence concerns the gene ESR1 and breast cancer.