ESR1 and triple-negative breast carcinoma: To the best of our knowledge, this is the first study reporting the estrogenic and antiestrogenic activities of E. bicolor latex extract and its identified phytochemicals in a steroid-regulated yeast system, and the antiproliferative activities of the latex extract and two of its phytochemicals, RTX and rutin in both ER-positive and triple negative breast carcinomas.