Currently, dipeptidyl peptidase-4 (DPP-4) inhibitors are used widely as a brand new type of oral hypoglycemic drug for treating T2DM (Ceriello et al., 2014; Pugazhenthi, Qin & Bouchard, 2015; Scheen, 2015), which decreases the deactivation of incretins. Here, DPP4 is linked to type 2 diabetes mellitus.