Taxa in the Clostridium XIVa cluster have been shown to induce the production of the anti-inflammatory cytokine IL-10 by T regulatory cells and inhibit the proinflammatory NF-κB pathway, implicated in tumor cell apoptosis (Hague et al., 1995; Atarashi et al., 2011; Lopetuso et al., 2013). This evidence concerns the gene IL10 and neoplasm.