Japan Team Finds Why Bone Tumors Develop in Young People

Tokyo, July 16 (Jiji Press)–A Japanese team has unraveled the mystery of why cancerous bone tumors near the knees tend to develop among adolescents, through its research into mice. Usually, a good balance is maintained between a function to promote cell proliferation and another to prevent cancer within osteoblasts, which help produce bone tissue. The team of researchers from the University of Tokyo and other institutions found that osteosarcoma occurs when this balance is disrupted. About 200 people develop osteosarcoma every year in Japan, and many of them are aged between 10 and 19. In many cases, the bone tumor occurs in the thigh or shin bones near the knees. But it was unclear why such tumors tend to concentrate in specific areas and develop especially among those going through puberty. Led by Yasuhiro Yamada, professor at the national university, the research team analyzed immature osteoblasts at the ends of long bones near the knees in growing mice. It found that cells in this area divided actively when the mice went through a growth period and that their DNA was prone to abnormalities. The team also discovered that a mechanism that detects these abnormalities and halts cell growth worked at the same time so as to prevent cancer, maintaining a balance between the different functions. It then focused on the p53 tumor suppressor gene, which often displays abnormalities in various cancer cases including osteosarcoma. When the team activated another cancer gene commonly found in osteosarcoma, abnormal cell growth was suppressed because the p53 restrained such activities. When the functions of the p53 were inactivated, no such brakes worked, resulting in the development of osteosarcoma, which also spread to the lungs. “We were able to unravel the mechanism of osteosarcoma at the cellular level,” Yamada said. “We hope that our findings will lead to the development of new treatments.” The team’s findings were published in the British journal Nature Communications. END [Copyright The Jiji Press, Ltd.]