We took advantage of the publicly available RNA-seq and survival data from TCGA and determined that seven differentially expressed genes (ALDH1B1, ASTL, CA7, CPLX4, KCNV2, MAGEE2 and TUBA3E) could be involved in breast cancer development, especially in Caucasian female patients with ER positivity. The gene discussed is ESR1; the disease is breast cancer.