The test is sequenced using Illumina high-throughput sequencers and accompanying kits. Conduct preliminary quality control on the samples, and the tumor cell content of the tissue samples shall not be less than 30%. Tissue DNA was extracted from tumor tissue samples according to the instructions of the QIAGEN DNA extraction kit. Samples qualified for quality control shall be arranged for further library construction. The extracted DNA samples were sequentially purified by fragment purification, terminal repair, splicing, fragment size selection, PCR amplification, product purification, library enrichment, and library product quality control. After qualified quality control, the constructed library was sequenced by Illumina matching kit. Bioinformatics analysis would be conducted.