Thus, in xenograft models of human colon carcinoma HCT116 and hepatoma HuH-7, activation of Nrf2 by hypoglycemic dipeptidyl peptidase-4 (DPP-4) inhibitors (a common class of drugs used in type 2 diabetes mellitus) or by sulforaphane significantly increased the risk of metastasis without increasing the incidence or growth rate of primary tumors (Wang et al., 2016). Here, DPP4 is linked to type 2 diabetes mellitus.