Of note, we noted that ROS–NRF2–HO-1 axis promoted DPP-4i-induced MMP-2, MMP-9, and VEGF levels (7), three well-known NF-кB-responsive targets (14), promoting us to investigate whether NF-кB activation is involved in DPP-4i-induced BC metastasis. The gene discussed is MMP9; the disease is breast cancer.