TNF and disease of the tendon: Other potentially interesting biomarkers for musculoskeletal diseases [25], such as tendinopathy, include TNF-α, interleukin 1 beta (IL-1β), basic fibroblast growth factor (bFGF), interferon gamma (IFN-γ), platelet derived growth factor BB (PDGF-BB) and vascular endothelial growth factor (VEGF).