ABSTRACT
Tamoxifen is a nonsteroidal antiestrogen that was first developed as an oral contraceptive. Although this use was found to be ineffective, it was postulated that an antiestrogen might have an anticancer effect on hormone-dependent malignancies such as breast cancer. The first evidence oftamoxifen's effectiveness in the treatment of breast cancer, presented by Cole et al. in 1971 (1 ), stimulated numerous preclinical and clinical studies. Mouridsen et al. published the first comprehensive clinical trial in 1978 (2), and tamoxifen has since become the most commonly used hormonal therapy for breast cancer.
