In order to verify the results of second-generation sequencing, DNA was extracted from 78 lung cancer brain metastatic tissues and 60 lung cancer non metastatic patients, and Sanger sequencing and EZH2 were performed in parallel_ G553C genotype analysis showed that out of 78 cases of lung cancer with brain metastasis, 49 cases were CC genotype, 26 cases were CG genotype, and 3 cases were GG genotype; Among the 60 tissues of non-metastatic lung cancer patients as controls, 49 were CC genotype, 9 were CG genotype, and 2 were GG genotype (Fig. 1C). The gene discussed is EZH2; the disease is metastasis.