Meanwhile, in 4T1-bearing NOD-SCID mice, we also observed that Sax or ALA treatments also enhanced GM-CSF levels in lung and liver metastasis tissues (Figures 8D, E), indicating that ROS–NRF2–HO-1–NF-кB axis play a crucial role in DPP-4i-driven GM-CSF secretion in BC cells. Here, HMOX1 is linked to breast cancer.