Single HR-positive breast cancers, i.e., ER-positive/PR-negative or ER-negative/PR-positive ones, have worse survival than ER-positive/PR-positive breast cancer, but better survival than ER-negative/PR-negative breast cancer, while survival in single ER-positive breast cancer is longer than that in single PR-positive breast cancer (29). The gene discussed is ESR1; the disease is breast carcinoma.