Integrity analysis revealed a significant difference in the time of 5 day (EGFR mutation DNA in plasma in the time of 5 day: 128.3333 copies/ml and 180 copies/mL in the squamous cell carcinoma, and large cell lung cancer group, respectively; P = 0.022; Fig. 4A) and 7 day (EGFR mutation DNA in plasma in the time of 7 day: 63.6842, 57.7778 and 100 in the squamous cell carcinoma, and large cell lung cancer group, respectively; P = 0.011, P = 0.006; Fig. 4A). The gene discussed is EGFR; the disease is lung large cell carcinoma.