Tamoxifen tablets are endocrine therapy and there is a relationship between the occurrence, development, and even progression of most breast cancers and endocrine. The estrogen and progesterone receptors of breast tumors are the key to determine the endocrine therapy. If estrogen receptors and progesterone receptors are positive, it is hormone-dependent breast cancer and endocrine therapy is effective. If estrogen receptor and progesterone receptor are negative, non-hormone-dependent breast cancer patients, endocrine therapy is poor in these patients. The choice of endocrine therapy depends on the stage of the tumor and the status of the hormone receptors, not all breast cancer patients need endocrine therapy.