Heilbronn et al. found that genes related to oxidative stress were down-regulated such as SOD1 and SOD2 (28), and Mindikoglu et al. found that the expression of other genes including the tumor activators POLK, NIFK, SRGN, CAMP, and D109, were downregulated (10), which are consistent with remitting oxidative effect and lowering cancer risk by IF. Here, POLK is linked to cancer.