AHR and colorectal cancer: It is expressed in many immune and stromal cells in the intestinal mucosa and plays a key role in maintaining the epithelial barrier, antibacterial defense through T helper 17/ILC3-epithelial crosstalk and limiting the development of colorectal cancer by promoting epithelial differentiation.7,11–17 As a transcription factor, AHR can regulate the expression of hundreds of genes, often in a cell type–specific manner.7,18–22 As a result, AHR has diverse functions in physiological and pathologic settings in the intestine.