NOX5 and malignant colon neoplasm: Knockdown of NOX5 did not affect the proliferative and colony forming ability of colon cancer cells, but it attenuated the inhibitory effect of PD on cell viability (Figures 7A, B; Supplementary Figures S5A, B) and cell colony formation (Figures 7C, D; Supplementary Figures S5C, D).