TGFB1 and hepatocellular carcinoma: Thrombospondin-1 (THBS1; upregulated in POAG LC cells) is a major activator of extracellular transforming growth factor beta 1 (TGFβ1) in fibrotic renal disease in the rat and is closely involved in angiogenesis in hepatocellular carcinoma [23,24].