H2AX and malignant colon neoplasm: In addition, to examine the mechanism explaining the chemopreventive effect of FeF on colony formation of colon cancer cells, Western Blotting was used to evaluate the effect of FeF on phosphorylation of MEK1/2, TOPK and its downstream targets, including the phosphorylation of histone H2AX, ERK1/2, and MSK 1 proteins in HCT 116 cells, which were relatively more sensitive to FeF.