FOXO1 and neoplasm: As shown in Figure 6E and F, overexpression of G6PD alone in control MDA-MB-231 cells led to stronger tumorigenicity at high ROS levels, while knockdown of FOXO1 significantly reduced tumor growth, but knockdown of FOXO1 had a minimal effect on tumor growth of G6PD-overexpressing cells, suggesting that the overexpressed G6PD is strongly tumorigenic at high ROS levels.