Vedolizumab/ENTYVIO, which is a humanized mAb against α4β7 integrin, a cognate lymphocyte receptor for MAdCAM-1, has been approved by the US FDA for clinical management of patients with moderately to severely active ulcerative colitis (https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/125476Orig1s046lbl.pdf, accessed on 16 October 2024). This evidence concerns the gene MADCAM1 and ulcerative colitis.