ESR1 and breast cancer: Furthermore, there was a correlation between PARP1 and BRCA1/2, and at the same time, with ERBB2, PGR, and ESR1 in the luminal A subgroup; such results can indicate that those breast cancer patients classified as subgroup luminal A can receive not only PARP inhibitors, but Anti-HER2 Monoclonal Antibodies, tamoxifen, or other drugs for positive ESR1 patients and antiPGR as therapeutic drugs.