Furthermore, since increased colonic inflammation is a major factor in the development and progression of hepatocellular carcinoma (HCC) [36] and microcystin-LR is considered to be a carcinogenic promoter of HCC [37], we speculate that the increased expression of colonic MCP-1 determined herein is involved in the effects of microcystins on HCC as well as CRC. This evidence concerns the gene CCL2 and colorectal carcinoma.