PPARD and metastatic malignant neoplasm in the lymph nodes: We then identified eight IRGs (IKBKB, LTBR, MIF, PPARD, PPIA, PSME3, S100A6, SEMA4B) as the best predictors by LASSO Logistic analysis and used these IRGs to construct a model to predict lymph node metastasis in patients with LUAD (AUC 0.75; 95% CI: 0.7064–0.7978), and survival analysis showed that the risk score independently affected patient survival.