IL4 and periodontitis: IL1B, IL4, IL6, IL10 were also ranked among leader genes, suggesting a central role for systemic inflammation in the genomic relationship between CRC and periodontitis; in particular, periodontitis may be linked to IBD, and, in turn, to CRC, both affecting the inflammatory pro-carcinogenic and tumor-associated environment and acting in an indirect way in the “inflammation-dysplasia” carcinogenic sequence, favoring colorectal cancer development.