Abstract: Objective  To investigate the relationship between gene mutation characteristics and immunological markers in patients with small cell lung cancer.Methods  From January 2019 to 2020, 155 patients with small cell lung cancer were admitted.Gene mutations were detected in these patients using target gene capture and sequencing method.Moreover,the tumor mutational burden(TMB)and expression of PD-L1 in some patients were detected.Results A total of 326 gene mutations were detected in the patients,the most significant of which were TP53 and RB1.Among the 8 genes with mutation frequency higher than 15%,patients with KMT2D,KMT2C,FAT1 and NOTCH1 mutations had higher TMB than those without mutation,and the difference was statistically significant(P<0.05).Conclusion The most common mutated genes in patients with small cell lung cancer are TP53 and RB1.KMT2D,KMT2C,FAT1 and NOTCH1 may be potential markers for the efficacy of immunotherapy in small cell lung cancer.

Key words: small cell lung cancer, gene mutation, PD-L1, TMB, correlation study