In 2019, Hollande et al. (12) reported using sitagliptin to recruit eosinophils into tumor tissue, and discovered a distinct mechanism by which the inhibition of DPP4i improves antitumor responses via higher concentrations of the chemokine eotaxin-1 and increased migration of eosinophils into solid tumors. This evidence concerns the gene CCL11 and neoplasm.