Expression of P-glycoprotein in high-grade osteosarcomas in relation to clinical outcome

High levels of P-glycoprotein in tumor cells of osteosarcoma appear to increase the risk of tumor relapse or death following surgery and chemotherapy. Osteosarcoma is a bone tumor that is often cancerous. Researchers studied the levels of the membrane pump P-glycoprotein in tumor cells of 92 patients with osteosarcoma who had surgery and chemotherapy. In 28 (30%) of the tumors, P-glycoprotein appeared at elevated levels in cells throughout the tumor. Tumors located at the end of bones closer to the torso tended to have higher P-glycoprotein levels. During a minimum follow-up of 63 months, the rate of tumor relapse or death during remission was 3.4 times higher in people with high P-glycoprotein levels. Poor response to chemotherapy also appeared to increase the likelihood of a poor outcome.