SLC15A1 and inflammatory bowel disease: Among these transporters, PEPT1 is abundantly expressed in the intestine and is found in the liver, bile duct, pancreas, and placenta.[11, 12] PEPT1 possesses sequence and substrate specificity similar to that of PEPT2 and mediates the uptake of dipeptides, tripeptides, and peptide‐like drugs in intestinal epithelial cells.[11, 12] Accumulating evidence has shown that PEPT1 plays a critical role in the initiation and progression of inflammatory bowel disease,[13, 14, 15, 16] but its function in tumors remains controversial.