Correlation Between Expression Of PD-L1 And Mutation Of EGFR And Clinicopathology In Non-small Cell Lung Cancer

Objective:To study the relationship between the expression of PD-L1 and the EGFR mutation and clinicopathological characteristics in non-small cell lung cancer.Methods:From June 2016 to June 2018,110 patients with non-small cell lung cancer diagnosed pathologically in the Department of Thoracic surgery,the first affiliated Hospital of Kunming Medical University,were collected.The mutation genes of EGFR and other non-small cell lung cancer(mainly 7 kinds)in fresh tumor tissues were detected by NGS.The expression of PD-L1 in paraffin sections of 110 cases of NSCLC was detected by ICH.Processed by statistical software IBM SPSS24.0,Usingχ2 test,When P<0.05 is considered to be statistically significant.Results:1.59 cases of EGFR mutations were detected,the mutation rate was 53.6%,the most common EGFR mutations were deletion of exon 37.3%(22/59)and L858R mutation 33.9%(20/59),mutation of exon 18(4 cases),and mutation of T790M EGFR(1 case),Exon 20 insensitive mutation in 3 cases,rare mutation in 4 cases,gene amplification in 3 cases;The mutation rate was 34.5%in males and 72.7%in females(P<0.001).The mutation rate was 26.3%in smokers and 68.1%in non-smokers(P<0.001).The mutation rate was 62.2%in lung adenocarcinoma,6.3%in squamous cell carcinoma and 66.7%in adenocarcinoma(P<0.001),but there was no significant difference in EGFR mutation in pathological subtypes of adenocarcinoma(P=0.137).Lymph node metastasis mutation rate was lower than that without metastasis(41.7%vs 63.5%),distant metastasis mutation rate was lower than that without distant metastasis mutation rate(38.5%vs 58.8%),the difference was statistically significant(P=0.044).The mutation rates of EGFR in stages Ⅰ,Ⅱ and Ⅲ-Ⅳ were 64.8%,44.4%,42.2%,respectively(P=0.048),but there was no significant difference between EGFR and age and lymph node metastasis(P>0.05).2.The expression of PD-L1 was positive in 24 cases(23.4%),low expression of PD-L1(1%≤TPS<50%)in 19 cases,high expression of PD-L1(TPS>50%)in 5 cases,and adenocarcinoma in 18 cases(20%).6 cases(37.5%)of squamous cell carcinoma,The positive rate of middle and late stage(III+IV)was 29.5%,which was higher than that of early stage(Ⅰ+Ⅱ)16.7%.The positive expression of PD-L1 was related to sex,age,smoking status and pathological type.There was no significant difference in pathological stage,lymph node and distant metastasis(P>0.005).In this study,the expression of PD-L1 was also observed in the pathological subtypes of lung adenocarcinoma.The positive rate of PD-L1 was 50%(9/18)when solid or solid component was found in lung adenocarcinoma.The positive rates of PD-L1 were 30%(3/10),26.3%(5/19),3.8%(1/26),3.8%(1/26)and 3.8%(1/26)respectively in micronipple,infiltration(unknown type),acinar type and papilla.No positive expression of PD-L1 was found in adherent type and mucus type,and there was significant difference(P<0.003).3.The positive rate of PD-L1 expression in patients with EGFR mutation was 13.6%(8/59),The expression rate of PD-L1 in EGFR wild-type patients was 31.4%(16/51),and the expression rate of PD-L1 in EGFR wild-type patients was significantly higher than that in EGFR mutants.The χ2 test showed that there was statistical difference between the two groups(P>0.05).There was no significant difference between the expression of PD-L1 and deletion of exon 19 and mutation of L858R in EGFR mutation site(P=0.113).In addition,we also evaluated the relationship between PD-L1 and other mutated genes in NSCLC,including 8 ALK rearrangements,13 KRAS mutations(1 comutation with EGFR),11 ROS1 rearrangements(including 2 co-mutations with EGFR and 4),BRAF mutations).There were 3 cases of MET amplification(including 1 case of),RET rearrangement with EGFR comutation),all of which had no significant difference with the expression of PD-L1 and PD-L1(P>0.05).Conclusion(s):1.The mutation rate of EGFR was higher in non-smoking,female and adenocarcinoma patients.2.The expression of PD-L1 was significantly correlated with the wild type of EGFR,and negatively correlated with the mutation of EGFR.There was no correlation between the expression of PD-L1 and the mutation site of EGFR,suggesting that the use of PD-L1 inhibitors would be more beneficial in the future,especially in the patients with EGFR advanced lung adenocarcinoma.,EGFR mutants preferred targeted therapy.3.The expression of PD-L1 was not correlated with clinical features and pathological types of lung cancer.However,the expression of PD-L1 is closely related to the pathological subtypes of lung adenocarcinoma with solid or micropapillary components,both of which suggest poor prognosis,which may be associated with tumor immune escape.Therefore,we speculate that the expression of PD-L1 may be an index to evaluate the immunogenicity of EGFR mutation in NSCLC,which should be paid more attention in the future.