Significant and Conflicting Correlation of IL-9 With Prevotella and Bacteroides in Human Colorectal Cancer

Our data consolidate antitumor immunity impairment and the presence of a distinct microbiota profile in the tumor microenvironment compared with the healthy mucosa counterpart. Relating the CRC cytokine profile with GM composition, we confirm the presence of bidirectional crosstalk between the immune response and the host's commensal microorganisms. Indeed, we document, for the first time, that <i>Prevotella</i> spp. and <i>Bacteroides</i> spp. are, respectively, positively and negatively correlated with IL-9, whose role in CRC development is still under debate.