NOX4 and neoplasm: Furthermore, analysis of data from laser-microdissected iCCA stromal samples revealed an increase in NOX4 expression in tumour stroma versus non-tumoral stroma (Fig. 4d) and a correlation of NOX4 expression with that of typical markers of CAF (ACTA2 and COL1A1) (Fig. 4e), suggesting that NOX4 expression may play a role in the activation of CAF during carcinogenesis.