Comparison Of EGFR Mutations In Malignant Pleural Effusion And Tumor Tissue Of Patients With Lung Adenocarcinoma

Objective:In this study,to investigate weather malignant pleural effusion samples can instead of tumor tissue samples used to test the epidermal growth factor receptor(EGFR)gene’s mutation instructing the clinical application of epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKI),using amplification refractory mutation system(ARMS),we tested EGFR gene’s mutation rates of both samples of patients with lung adenocarcinoma and malignant pleural effusion which have been confirmed by pathology,and compared the differences by statistical calculation.Methods:We collected 28 patients of lung adenocarcinoma(male 17,female 11;mean 61 years old,rang 48-79)with malignant pleural effusion which have been confirmed by pathology in the Second Affiliated Hospital of Dalian Medical University from December 2014 to December 2015.The Inclusion criteria were: 1.The patients of lung adenocarcinoma are with stage Ⅲb ~ Ⅳ and malignant pleural effusion confirmed by histology or cytology.2.Their expected survival time is more than 2 months,and they have no severe organ dysfunction.3.The patients didn’t take any anticancer drugs and biological agents before this study.The tumor tissue samples were obtained by Pleural biopsy,CT-guided percutaneous lung puncture or Cytoreductive surgery,and fixed in 4% formaldehyde.Malignant pleural effusion samples were directly obtained by the closed chest drainage(thick tube or capillary tube),150 ml per patients.Using human EGFR mutation detection kit by ARMS method,we tested the gene mutation of exon 18,19 and 21.We read the results according to the specification requirements of instruction in the kit,and submitted the corresponding reports.We analyzed the collected data by SPSS 19.0 software,and compared the difference of EGFR gene mutation rate between tumor tissue and malignant pleural effusion samples by X~2 test.The P value <0.05 was considered the difference is significant.Results:The EGFR gene mutation rate was 57.1%(16 / 28)in 28 cases of lung adenocarcinoma tumor tissues.There are 11 cases with deletion mutation in exon 19,5 cases with point mutation L858 R in exon 21,and 0 cases point mutation G719 X in exon 21.In corresponding lung adenocarcinoma malignant pleural effusion samples,the EGFR gene mutation rate was 53.6%(15/28).There are 11 cases with deletion mutation in exon 19,4 cases with point mutation L858 R in exon 21,and 0 cases point mutation G719 X in exon 21.We got X~2 = 0.072,P = 0.788> 0.05 by X~2 test using SPSS 19.0 software,indicating the difference of EGFR gene mutation rates was no significant between tumor tissue samples and malignant pleural effusion samples(P> 0.05).Conclusion:For advanced and unresectable lung adenocarcinoma patients,it is difficult to obtain tumor tissue samples,while we can get pleural effusion by easy operation.Therefore it is feasible to test EGFR gene mutation in pleural effusion samples instead of tumor tissue sample to instruct the use of EGFR-TKI in the clinical therapy.