Elwood Jensen (1920–2012)
Breast cancer is the most common cause of cancer deaths in women worldwide and the second-leading cause in the Western world. Today, tamoxifen (Nolvadex) is the most widely used drug for the treatment of early and advanced breast cancer in selected women of all ages, decreasing cancer recurrence by one-half and risk of death by 25 percent.
Tamoxifen can also prevent the development of breast cancer in women at high risk. Tamoxifen was originally synthesized in 1962 at ICI Pharmaceuticals (now Astra-Zeneca) in Cheshire, England. The compound, a nonsteroidal antiestrogen, was intended as a potential anti-fertility drug, although it stimulated ovulation instead of suppressing it in humans. A failed contraceptive didn’t have much market potential, but after laboratory and human studies pointed to the compound’s promise in preventing the development of breast cancer in high-risk women, it was approved for use in the United Kingdom in 1973 and in the United States in 1977.
Tamoxifen is not effective in all cases of breast cancer. Around the turn of the twentieth century, removal of the ovaries was shown to halt the growth of advanced breast cancer. In the 1960s, Elwood Jensen at the University of Chicago found that estrogen receptors (ER) were present in some breast cancer tumors, while not in others. If an ER receptor is present (ER+)—as it is in 50–70 percent of patients—these tumors require estrogen for their growth. Tamoxifen works by blocking the ER on the tumors, thus preventing their growth.
In addition to its anticancer actions, tamoxifen produces a complex array of effects—some bad, some good. It is generally accepted that tamoxifen therapy is most effective for a maximum of five years, but one of the potential problems associated with its long-term use is an increased risk of endometrial (uterine) cancer. On the flip side, tamoxifen reduces the loss of bone, and a pharmacologically related drug, Evista, is used to treat and prevent osteoporosis.
SEE ALSO Drug Receptors (1905), Estrone and Estrogen (1929), Clomid (1967), Evista (1997), Herceptin (1998).
The Chain Bridge across the Danube River in Budapest, Hungary, is lit pink in support of breast cancer awareness.