Increased plasma levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in lung and breast cancer are altered during chest radiotherapy.

Purpose: Does the release of plasma matrix metalloproteinase-9 (MMP-9) by radiation-activated airway epithelial cells and infiltrating inflammatory cells play a role in the radiation damage or repair process in the lungs? We evaluated lung damage by ionizing radiation using plasma levels of MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and MMP-3 as biologic markers of tissue damage, and also their relationship to changes in pulmonary epithelial permeability, clinical signs and symptoms, and lung structural changes.

Methods And Materials: Seven serial studies were conducted in each of 8 patients undergoing chest radiotherapy (RT) for lung or breast cancer, beginning before the first treatment (baseline) and then biweekly to approximately 100 days during and after RT. Chest radiographs were monitored for each patient.