NOX4 and hepatocellular carcinoma: The role of NOX4 in the tumour cell has been controversial, being defined as pro-tumorigenic in some tumours,14 and suppressor in others, including HCC.13 Interestingly, our data revealed that NOX4 expression is restricted to CAF from the TME in iCCA, which allows its therapeutical inhibition without undesired side effects on tumour cells.