Estrogen for the Treatment and Prevention of Breast Cancer: A Tale of 2 Karnofsky Lectures

In 1971, Sir Alexander Haddow et al. delivered the inaugural David A. Karnofsky lecture at the American Society for Clinical Oncology. This award was designated American Society for Clinical Oncology's highest, as he had used translational research to identify the first clinical therapy, that is, synthetic estrogens to treat breast cancer. His lecture was entitled "Thoughts on Chemical Therapy." For 40 years, high-dose synthetic estrogens were used as palliative therapy, for some advanced breast cancer patients 5 years following menopause. Mechanisms were unknown. Tamoxifen, a failed "morning-after pill," is an antiestrogen in estrogen receptor-positive breast cancer, which was subsequently used to treat all stages of breast cancer and to prevent breast cancer. In 2008, Jordan was selected to present the 38th Karnofsky lecture entitled: "The Paradoxical Action of Estrogen in Breast Cancer-Survival or Death?" Unexpectedly, through a study of acquired resistance to long-term tamoxifen therapy, estrogen-induced apoptosis in long-term estrogen-deprived breast cancer was deciphered in Jordan's laboratory. These data and the biological rules established under laboratory conditions provided molecular mechanisms to aid in the interpretation of the Women's Health initiative in the United States and the Million Women Study in the United Kingdom. In addition, by establishing laboratory models to understand mechanisms of estrogen-induced apoptosis, new estrogen derivatives were successfully evaluated in the laboratory and tested as candidates for women after the therapeutic failure of antiestrogenic strategies to treat breast cancer. For the future, the knowledge obtained about estrogen-induced apoptosis in cancer holds the promise of discovering new therapies to control or cure cancer in general.