The most common cancer in men, prostate cancer can be effectively treated with surgery or radiation when detected early. But advanced prostate cancer is usually treated by drugs or surgery aimed at reducing the level of testosterone and other male hormones, or androgens, that stimulate cancer cell growth. While the disease usually regresses after such treatment, prostate cancer invariably comes back, although it's not clear why it recurs and progresses.
The UNC study, published April 15 in the journal Cancer Research, indicates that the gene HER-2 is a key culprit in prostate cancer recurrence. The findings also suggest a new treatment strategy for targeting HER-2 in patients with advanced prostate cancer.
HER-2 refers to human epidermal growth factor receptor 2. The gene helps control how cells grow, divide and repair themselves, and directs the production of a special protein called HER-2 tyrosine kinase. This protein acts as receptors on the cell membrane, and when activated by external hormones, it promotes cell growth and division.
In about one in four breast cancers, a genetic mutation creates too many HER-2 receptors. This helps spur rapid cancer cell growth. While treatment with the antibody drug Herceptin can be effective in slowing breast cancer growth, this is not the case in prostate cancer, researchers said.
"The treatment with the antibody has been a uniform failure in prostate cancer because the gene is not over-expressed in this disease. We need a different approach to attack HER-2 in prostate cancer," said the study's senior author, Dr. Young Whang. He is an assistant professor of medicine and medical oncologist at UNC and a member of UNC Lineberger.