Improved diagnostic techniques for prostate cancer, the most common cancer among American men, have led to a threefold increase in the rate of diagnosis since 1988. But that presents physicians with a dilemma: Many of these early cancers are relatively benign and do not warrant aggressive intervention. How is the physician to tell which cancers will go on to develop life-threatening metastases?
Harvard researchers may have found a way. In the December issue of Nature Medicine, a research team led by Lere Bao, instructor in surgery at Children's Hospital, Boston, reports the identification and genetic description of a telltale molecule: thymosin B15, a protein involved in cell motility. The researchers found that, in an animal model, the protein gears up the cancer cell's ability to move around the body, which is part of the progression of metastasis. They also note that thymosin B15 is not expressed in normal or benign human prostate cells but appears at high levels in human prostate cancers with high metastatic potential.
Apparently, the protein helps the cancer cell break free of its attachments to neighboring cells and surrounding tissue, allowing it to course through the body and form secondary tumors elsewhere.
Other authors are Massimo Loda and Robert Stewart, Beth Israel Deaconess Medical Center; Paul A. Janmey, Brigham and Women's Hospital; and Bela Anand-Apte and Bruce R. Zetter, Children's Hospital.