Taken together, the mRNA/protein up-regulations are found according to a hypothesis of gain of SLC15A4/PHT1 function associated with GI inflammation pathways and, particularly, to IBD; dysregulation, i.e., increased expression of SLC15A4/PHT1 is revealed as deeply associated to inflammation in patients’ intestinal epithelium, allowing to point SLC15A4/PHT1 gene as a novel marker to be exploited in studying IBD manifestation. Here, SLC15A4 is linked to inflammatory bowel disease.