AHR and Cowden disease: Li et al. discovered that the AhR signal plays a significant regulatory role in the expression of CD117 on the surface of ILC3 (type 3 innate lymphoid cells), and in patients with Crohn’s disease (CD), attenuation of the AhR signal can lead to the transformation of ILC3 into ILC1, thereby increasing inflammation in the terminal ileum (Li J. et al., 2016; Li M. et al., 2016).