MMP1 and rotator cuff syndrome: Blaine et al.7reported that tumor necrotic factor (TNF)‐α, IL‐1α, IL‐1β, IL‐6, cyclooxygenase (COX)‐1, COX‐2, matrix metalloprotease (MMP)‐1, and MMP‐9 are overexpressed in the subacromial bursa in patients with a rotator cuff tear.