ERCC2 and laryngotracheoesophageal cleft: The limitation of this study is that there is no accurate information about the evaluation of chemotherapy effect and tissue samples of patients, so it is impossible to explore the relationship between SNPs and chemotherapy effect or protein expression level of lung cancer, which limits the exploration of the underlying mechanisms of the association between ERCC1, ERCC2 SNPs, haplotypes, and quality of life of LC patients.