Bogoaert et al. [37] studied differential mucosal expression of genes involved in differentiation (IL-6, IL-1β, TGF-β, IL-23A and STAT3) and recruitment of Th17 cells (CCR6 and CCL20) and observed enhanced expression of these genes in ileal and colonic samples from UC and CD patients. This evidence concerns the gene IL23A and Cowden disease.