To further elucidate the function of CD103+ T cell in preventing oxidative damaged cell‐derived tumorigenesis, we bred WT and Med23−/− mice with Sftpc‐DreER; K‐rasRox–Stop–Rox–G12D/+ mice (designated Med23−/−‐KRAS (G12D) mice), which express the mutant KRAS (G12D) in AT2 cells upon tamoxifen administration and develop ROS‐dependent lung adenocarcinoma at 9 weeks old (Figure6A,B).[54] Histology analysis revealed that Med23−/− mice developed more tumors after the induction of KRAS (G12D) (Figure 6B,C). Here, KRAS is linked to lung adenocarcinoma.