TGFB1 and neoplasm: TGF-β is able to repress proliferation and induce apoptosis in HCC cells that resemble earlier stages of tumour development, while cells resembling advanced stages are able to escape from TGF-β suppressor functions by different mechanisms and exploit its pro-tumorigenic properties, becoming more migratory and invasive.22–24 Since these processes remain largely understudied in iCCA, we performed in vitro studies to evaluate the effects of TGF-β1 on the viability and morphology of seven human iCCA cell lines (Fig. 2a, b).