ESR1 and breast cancer: The first anti‐cancer drug to have experimented with in tocotrienol adjuvant therapy, was the breast cancer drug, tamoxifen which was unsuccessful with the researchers concluding that estrogen receptor‐positive‐early stages of breast cancer [of tumor, nodes, and metastases (TNM) Stages I and II] remained unresponsive to the tocotrienol‐rich‐fraction (TRF) administered with tamoxifen.80