Although recent data suggest a potential role of DPP-4 inhibition in CXCL10-mediated lymphocyte trafficking in melanoma B16F10-bearing mice (12), very little information is available for the potential effect of DPP-4i on tumor immune microenvironment, especially on tumor-infiltrating immune-suppressive cells in BC progression. The gene discussed is CXCL10; the disease is neoplasm.