Researchers at Mount Sinai School of Medicine report that the thyroid hormone, triiodothyronine (T3), may be a useful marker for prostate cancer aggressiveness. Prostate cancer usually progresses very slowly and in many cases, especially among older men, requires no other treatment than "watchful waiting". The problem, of course, is to identify those cases that do require aggressive treatment (surgery and radiation) in order to prevent metastasis. It is well established that T3 is required for the growth of prostate cancer cells in vitro. The researchers measured T3 levels in 208 men aged 46 to 96 years. Twenty of the men had an enlarged prostate (benign prostatic hyperplasia or BPH), 161 had localized prostate cancer, and 27 controls had neither BPH nor prostate cancer. The researchers found that men with BPH had significantly higher levels of T3 than did the controls and the prostate cancer patients. Prostate cancer patients also had significantly higher levels than the controls, but lower levels than the men with BPH. The researchers conclude that T3 may be a useful biomarker for prostate cancer, but that more work is required to definitely establish this. They also suggest that new therapies for BPH and prostate cancer could perhaps be directed towards inhibiting the mitogenic (cell dividing) effects of T3.
Lehrer, Steven, et al. Serum triiodothyronine is increased in men with prostate cancer and benign prostatic hyperplasia. Journal of Urology, Vol. 168, December 2002, pp. 2431-33