ESR1 and breast cancer: Our analysis found enrichment of multiple gene sets that were associated with breast cancer and estrogen receptor including MORF_ESR1 (nominal p value = 0.001) and GSEA sets indicating roles in FIRESTEIN_PROLIFERATION (nominal p value = 0.001), and TAVAZOIE_METASTASIS (nominal p value = 0.001, Fig. 1c and d).