Chang's findings are most relevant for patients with advanced prostate cancer, who typically receive hormone therapy after other treatments such as surgery or radiation. With hormone therapy, physicians blunt the effects of male hormones like testosterone to bring the disease in the prostate to a halt. One form of hormone therapy works by blocking the androgen receptor. Androgen deprivation therapy is generally very effective for a year or two, but for reasons that no one has understood, the cancer ultimately returns.
"When a man receives hormone therapy, initially the treatment works well, and his PSA (prostate specific antigen) level goes down," said Edward Messing, M.D., a urologist and an author of the paper. "But inevitably, the PSA will start climbing again, and that is usually the first sign that the treatment is beginning to fail. It's a sign that the cancer in the prostate is making a comeback."
In work funded by the National Cancer Institute, Chang's team found that blocking the receptor indeed prevents some cells in the prostate from growing, just as scientists expected. But Chang's team unexpectedly found that blocking the receptor actually spurs other prostate cells to grow.
"The androgen receptor acts differently in different cells in prostate tissue," said Chang. "It's always been assumed that blocking the androgen receptor will stop all prostate cells from growing, but we have found that that's not the case. Since current treatment acts non-specifically on all the cells having androgen receptors in the prostate, blocking the androgen receptor will give mixed results."
The team found that, as expected, the androgen receptor in prostate sup
|Contact: Leslie White|
University of Rochester Medical Center