Noh Y, et al. - In this population-based cohort study involving 223,530 Korean diabetic patients with newly diagnosed primary cancer (2009–2011), researchers assessed the link between different glucose-lowering treatments, including dipeptidyl peptidase-4 (DPP-4) inhibitors and metformin, both with potential nuclear factor erythroid 2-related factor 2 (NRF2) modulating effects, and new-onset metastatic cancer. Five study cohorts were characterized: no-antidiabetic drugs (no-AD), metformin, DPP-4 inhibitors, metformin+DPP-4 inhibitors, and insulin treatment. For cohort entry, 18,805 patients in metformin, 1,865 in DPP-4 inhibitors, 31,074 in metformin+DPP-4 inhibitors, and 1,895 patients in insulin groups were identified after propensity score (PS) matching in a 1:1 ratio against the no-AD group. These participants were analyzed against the corresponding number of no-AD patients in each PS-matched comparison pair. DPP-4 inhibitor therapy vs no-AD therapy was not found to be related to a significant risk of cancer metastasis, regardless of patient age and sex, except after thyroid cancer, while metformin treatment was associated with decreased metastatic risk among type 2 diabetes patients with pre-existing cancer.