Why Certain Cancers Spread to Bones.

• Position: Brief Article

Bones are among the most common places for aggressive breast and prostate cancer to spread, yet other types of cancer may leave this fertile area alone. Why is this so? "Perhaps breast and prostate cancer possess inherent capabilities which not only direct them to bone, but also enable them to survive, proliferate, and colonize in bone," suggests Toshiyuki Yoneda, professor of medicine, The University of Texas Health Science Center at San Antonio. "One important goal of research in this area is to identify these capabilities at the molecular level."

Complex cellular processes contribute to the progression of bone metastasis. Prostate and breast cancer distort normal regulation of bone cells, affecting both the bone-building and bone-destroying cells. Those that form bone are known as osteoblasts, and the cells that break down bone are called osteoclasts. The work of these bone "masons" is continual and lifelong. In the adult skeleton, old bone is replaced by new within about 60 days. That is why a fracture generally can heal in that amount of time. In children, bone...