基于NGS技术及PD-1/PD-L1检测对同时性多原发肺癌的诊断价值初探

Diagnosis of synchronous multiple primary lung cancer(sMPLC)base on the detection of PD-1/PD-L1 using NGS technology

目的基于二代基因测序(NGS)技术及程序性死亡受体-1/程序性死亡受体配体-1(PD-1/PD-L1)检测对同时性多原发肺癌(sMPLC)组织的基因分子特征进行分析及分子诊断进行探索。方法收集2018年7月至2019年11月于中山大学附属第一医院胸外科确诊为同时性多原发肺癌患者组织标本及临床资料,通过NGS及免疫组化Elivision法检测sMPLC中PD-1和PD-L1蛋白的表达,分析其基因突变情况及PD-1/PD-L1蛋白表达情况。结果PD-1在sMPLC组织中阳性表达率为92.9%(13/14),PD-L1在sMPLC组织中阳性表达率为85.7%(12/14)。同一患者不同病灶之间表达不一致率为71.5%。在sMPLC肿瘤细胞中PD-1蛋白表达量与在细胞间质中的淋巴细胞中PD-1蛋白表达量差异有统计学意义(P=0.01),突变频率最高的基因为表皮生长因子受体(EGFR)基因,频率83.3%(10/12)。以21外显子EGFR L858R频率最高(7/10),sMPLC驱动基因突变均合并有伴随突变,同一患者的不同病灶之间有存在相同的伴随突变均为单核苷酸位点突变(SNV),未发现拷贝数变异(CNA)和基因重排或基因融合的共同伴随突变。sMPLC病灶中肿瘤突变负荷(TMB)值差异有统计学意义(P=0.02),且PD-L1在sMPLC组织中的表达量与TMB值呈正相关(r=0.609,P=0.036)。结论基于大panel的NGS测序及PD-1和PD-L1的检测,对于同时性多原发肺癌的诊断及后续的靶向及免疫治疗的评估有着一定的临床参考意义。

Objective To investigate the genetic mutation characteristics and molecular diagnosis of synchronous multiple primary lung cancer(sMPLC)based on the detection of programmed cell death-1/programmed cell death-ligand 1(PD-1/PDL1)using the next generation sequencing(NGS)technology.Methods The tissue samples and corresponding clinical data of patients with simultaneous multiple primary lung cancer diagnosed by Thoracic Surgery in the First Affiliated Hospital of National Sun Yat-sen University from July 2018 to November 2019 were collected.And the expression of PD-1 and PD-L1 in sMPLC was detected by Elvision immunohistochemistry,and the mutation characteristics were detected by NGS.Results In sMPLC,the positive expression rate of PD-1 was 92.9%(13/14),and the positive expression rate of PD-L1 was 85.7%(12/14).The rate of discordance was 71.5%between different lesions in the same patient.The expression of PD-1 protein in SMPLC tumor cells was significantly different from that in lymphocytes(P<0.01).The highest frequency of mutation was epithelial growth factor receptor(EGFR)gene,83.3%(10/12).Most of the EGFR mutations were 21 exon EGFR L858 R(7/10).The driven gene mutations of sMPLC were accompanied with single nucleotide variant(SNV);no concomitant mutations of copy number alteration(CNA)and gene rearrangement or gene fusion were found.There was significant difference in tumor mutation burden(TMB)value between sMPLC lesions(P=0.02),and the expression of PD-L1 in sMPLC tissues was positively correlated with TMB value(r=0.609,P=0.036).Conclusion The detection of NGS based on large panel and PD-1 and PD-L1 may benefit for the clinical diagnosis of multiple primary lung cancer and the evaluation of targeted immunotherapy.