Clinical Significance Of PD-L1 Expression In Bone Metastases Of Non-small Cell Lung Cancer,EGFR Mutation And PD-L1 Expression In Bone Metastases And Heterogeneity Of Primary Lesions Of Lung Cancer

Background and ObjectivesLung cancer is one of the most common tumors worldwide,with high morbidity and high mortality.Non-small cell lung cancer is the most common histological type of lung cancer,accounting for about 85%of the total number of lung cancer patients.Bone metastasis is one of the main sites of hematogenous metastasis in advanced NSCLC.About 1/3 of patients have bone metastasis as the first symptom,and the occurrence of bone metastasis often indicates a poor prognosis for patients.Although molecular targeted therapy has significantly improved the prognosis in recent years,there are still problems such as late drug resistance.In recent years,major breakthroughs have been made in immunotherapy,which mainly reverses the process of immunosuppression and changes the tumor microenvironment.Biomarkers that have been reported in many studies include tumor mutation load,tumor infiltrating lymphocytes,PD-L1,etc.,and PD-L1 detection is used as a prediction of PD-1/PD-L1 immune checkpoint inhibitors for the first-line and second-linetreatment of advanced NSCLC Biomarkers for predicting the efficacy of such treatments have been written into the NCCN guidelines to guide the clinical immunotherapy of NSCLC patients.For patients with obvious symptoms of bone metastases,especially for patients who require surgery due to symptoms of bone metastases,the pathology of bone metastases is often obtained before the primary tumor,and such patients are often not suitable for surgery due to advanced lung cancer,and it is difficult to obtain Primary tumor specimens.However,the process of bone metastasis in NSCLC is complicated,and the mechanism is not yet fully understood.There is a lack of research on the expression of PD-L1 in tumor cells in bone metastases and clinical treatment.Therefore,this study aims to explore the relationship between PD-L1 expression in bone metastases and prognosis and clinical indicators.And the difference in the expression of EGFR and PD-L1 between the primary tumor and bone metastases in lung cancer patients was studied to explore the reasons for the poor efficacy of immunotherapy in patients with lung cancer bone metastases.Methods1.Clinically collect pathological sections of patients with NSCLC bone metastases in our hospital,and count the positive rate indicators after PD-L1 staining;at the same time,collect clinicopathological characteristics(age,gender,pathological type,EGFR mutation,Preoperative radiotherapy and chemotherapy,etc.);real-time follow-up,statistics of dynamic changes in clinical characteristics and prognostic indicators(OS,etc.)of such patients;statistical analysis of the correlation between tumor cell PD-L1 expression and clinical indicators and its relationship with patients after sufficient sample volume Correlation with prognosis:Screen patients who have undergone immunotherapy,evaluate the correlation between PD-L1 expression in bone metastases and the prognosis of immunotherapy patients,and further discuss and analyze the significance of evaluating PD-L1 expression in bone metastases.2.Collect specimens from patients with bone metastasis of lung cancer in our hospital,prepare formalin-fixed paraffin-embedded tumor tissues,use PCR technology and amplified PCR product fragment length analysis to check exon 18G719X point mutation,exon 19 Exon 19-Del deletion mutation,exon 20 T790M point mutation,exon 21 L858R point mutation existed,and according to the detection results,the positive rate of EGFR in patients with primary lung cancer was compared with the positive rate of EGFR detected in bone metastases analyze.At the same time,formalin-fixed paraffin-embedded tumor tissues were prepared from patients with bone metastasis in our hospital,and the positive rate of PD-L1 expression in lesions was counted after immunohistochemical staining(with a limit of 1%).According to the test results The positive rate of PD-L1 in patients with primary lung cancer and the positive rate of PD-L1 detected in bone metastases were compared and analyzed,and the differences in the expression of EGFR and PD-L1 between the two were statistically analyzed,so as to explore the reason for poor performance of immunotherapy for patients with bone metastases of lung cancer.ResultsEffect of PD-L1 expression in bone metastases on patients with bone metastases and overall survival:PD-L1 expression negative group and positive group were defined by PD-L1 expression 1%,5%and 10%,univariate and multivariate Regression analysis showed that the overall survival of lung cancer in the PD-L1 positive bone metastases group was not significantly different from that in the PD-L1 expression negative group,(P=0.876;P=0.156;P=0.436),the bone metastases in the PD-L1 negative and positive groups There was no statistical difference in postoperative survival(P=0.536;P=0.788;P=0.300).The relationship between the expression of PD-L1 in bone metastases and clinical factors:the results of variance analysis suggested the relationship between the expression of PD-L1 in bone metastases and clinical factors:the results suggested that the expression of PD-L1 in bone metastases was related to the patient’s smoking history and surgery history.There was a significant correlation between soft tissue infiltration around the anterior bone metastases(P=0.050 and P=0.023,respectively),which may be related to the occurrence of extrabone metastases in patients,but the statistical results were not statistically significant(P=0.100).In contrast,gender,number of bone metastases,first bone metastases,history oflung surgery,history of preoperative lung radiotherapy,history of preoperative chemotherapy had no significant correlation with the expression of PD-L1 in bone metastases(P=0.125,P=0.509,P=0.283,P=0.974,P=0.293,P=0.828).Formalin-fixed and paraffin-embedded tumor tissues were obtained from 128 patients with bone metastases of lung cancer in our hospital(including 97 cases of primary lung cancer and 31 cases of bone metastases),and PCR technology was used to amplify PCR products.Fragment length analysis was used to check the G719X point mutation in exon 18,the 19-Del deletion mutation in exon 19,the T790M point mutation in exon 20,and the L858R point mutation in exon 21.The EGFR positive rate was compared with the EGFR positive rate detected in bone metastases,and it was found that there was a significant difference between the two results(P=0.013).ConclusionAt the same time,formalin-fixed paraffin-embedded tumor tissues were prepared from 118 patients with bone metastases of lung cancer in our hospital(including 69 cases of primary lung cancer and 49 cases of bone metastases),and were stained with immunohistochemistry.The positive rate of PD-L1 expression in lesions was counted(with a limit of 1%).According to the test results,the positive rate of PD-L1 in patients with primary lung cancer was compared with the positive rate of PD-L1 detected in bone metastases.It was found that both The results were not significantly different(P=0.381).