Molecule May Be a Marker for Deadly Prostate Cancer

Improved diagnostic techniques for prostate cancer, the most commoncancer among American men, have led to a threefold increase in the rateof diagnosis since 1988. But that presents physicians with a dilemma: Manyof these early cancers are relatively benign and do not warrant aggressiveintervention. How is the physician to tell which cancers will go on todevelop life-threatening metastases?

Harvard researchers may have found a way. In the December issue of NatureMedicine, a research team led by Lere Bao, instructor in surgery atChildren's Hospital, Boston, reports the identification and genetic descriptionof a telltale molecule: thymosin B15, a protein involved in cell motility.The researchers found that, in an animal model, the protein gears up thecancer cell's ability to move around the body, which is part of the progressionof metastasis. They also note that thymosin B15 is not expressed in normalor benign human prostate cells but appears at high levels in human prostatecancers with high metastatic potential.

Apparently, the protein helps the cancer cell break free of its attachmentsto neighboring cells and surrounding tissue, allowing it to course throughthe body and form secondary tumors elsewhere.

Other authors are Massimo Loda and Robert Stewart, Beth Israel DeaconessMedical Center; Paul A. Janmey, Brigham and Women's Hospital; and BelaAnand-Apte and Bruce R. Zetter, Children's Hospital.