As shown in Fig. 2C and D, the expression of MAGEA3 (P = 0.0021) and MAGEA4 (P < 0.0001) in serum exosomes were high expression and MAGEA3 level was positively correlated with lymph node metastasis of LUAD patients (Table 2). The gene discussed is MAGEA4; the disease is metastatic malignant neoplasm in the lymph nodes.