TNFRSF1A and osteoarthritis, hip: The protein expression patterns of tumor necrosis factor receptor 1 (TNFR1/CD120a), interleukin-6 (IL-6), and transforming growth factor-beta 1 (TGF-β1) were evaluated in synovial tissue specimens obtained from patients with hip osteoarthritis (HOA) and from control (CTRL) subjects without osteoarthritis.