IL1B and obesity due to melanocortin 4 receptor deficiency: Thus, the gut microbiota of CRC patients with obesity is characterized by the presence of a higher abundance of opportunistic pathogens (such as Prevotella, Fusobacterium nucleatum, Enterobacteriaceae, and Escherichia coli), which may impair intestinal barrier function (increased circulating zonulin levels), and may contribute to inflammatory processes related to CRC by means of increasing the production of inflammatory molecules such as IL-1β and TMAO.