TGFB1 and carpal tunnel syndrome: Transforming growth factor-beta (TGF-β) plays a critical role in the regulation of extracellular matrix gene expression67, and several previous studies have reported the role played by TGF-β and the TGF-β/Smad signalling pathway in the development of SSCT fibrosis in CTS68,69, including the finding that the inhibition of TGF-β1 in SSCT fibroblasts from CTS patients resulted in the down-regulation of several fibrosis-related genes and the inhibition of Smad activity68.