Ongoing research on immunohistochemical biomarkers for diagnostic and therapeutic purposes on EoE has some promising results; i.e., the expression of ALOX15 in the esophageal epithelium may be useful for the diagnosis of EoE in cases not meeting the threshold histological criteria and a low expression of filaggrin with an overexpression of periostin are considered specific for EoE diagnosis [81]. This evidence concerns the gene POSTN and eosinophilic esophagitis.