MicroRNA Related To EGFR In Nonsmoking Female Lung Carcinomas

ObjectiveLung cancer as one of the most commonly diagnosed cancers as well as the leading cause of cancer death globally,accounts for around 1095 000 new cancer cases and 951 000 deaths each year in men,and 513 600 cases and 427 400 deaths in women.The incidence of lung cancer in male patients was decreasing while the incidence of female rising.Female nonsmoking lung cancer patients were different from the male patients in several ways including epidemiological factors,clinical and pathological features,biomarkers,therapy and prognosis.Moreover,EGFR mutations were found more frequently in east Asian nonsmoking women.While,the mechanism need clarification.And miRNAs play key roles in the regulation of EGFR pathway,since the modulator role in development of carcinomas.The relationship of miRNA and EGFR needs clarification.In addition,there were rare reports on correspondence between tissue and plasma miRNA expression.Our study used TaqMan Low Density Array to explored the miRNA expression profile of tissue and plasma,screening for differential expression miRNAs,then validate in large population,analysising miRNA expression correspondence and its relationship with EGFR mutation and with metastasis and prognosis,as well as with female physiology and fertility factors.MethodsIn our molecular epidemiological study,130 female nonsmoking lung cancer patients with both plasma and tissue samples were first investigated by the epidemiological survey.Then DNA sequencing analysis was done to get the mutation status of EGFR exon 18-21.Then TaqMan low density microRNA array were used to screening for EGFR related miRNA in 4 patients’ paired tissue and plasma.Then 4 miRNAs(miR-155,miR-25,miR-16 and miR-133a)were chosen for further validation after synthesizing the results of array results,reference report and bioinformatics prediction.Verification study was done in tissue as well as in plasma using qRT-PCR.Results(1)We cannot find a correspondence between paired plasma and tissue miRNA expression in female nonsmoking NSCLCs,Spearman rank correlation tests of miR-155,miR-25,miR-16 and miR-133a have P value of 0.6637,0.5299,0.1361 and 0.3413.(2)In our study,the mutation rate of EGFR was 54.62%in nonsmoking female lung cancer patients.An older age of menarche was associated with a protective effort of EGFR mutations in nonsmoking female NSCLCs(OR=0.376,95%CI=0.146-0.970).Tissue miR-25 and miR-133a expression were found to be associated with EGFR mutation status(with P value 0.0005 and 0.0454).Moreover,miR-16 was associated with EGFR in advanced stage in plasma(P=0.0005).(3)MiR-16 was upregulted in the patients with a later menopause in plasma(P=0.0294).While,miR-133a was found to be related to EGFR mutation status in different female physiology and fertility subgroup.(4)An association as found between lymph node metastasis and EGFR mutation(OR=0.176,95CI%=0.035-0.896).We also discovered the expression of miR-25 in tissue was associated with lymph node metastasis(P=0.0071)and with stage(P=0.0445).While plasma miR-133a was associated with distant metastasis,with a higher expression in patients with distant metastasis(P=0.0277).Conclusion(1)Tissue miRNA expression was not correspond with the paired plasma miRNA expression in female nonsmoking NSCLCs.(2)MiR-25 and miR-133a may associated with EGFR mutation by molecular mechanism;miR-16 expression level in plasma may probably become biomarker which screening for EGFR mutation in NSCLC with advanced stage.(3)MiR-16,miR-133a expression level may associated with female physiology and fertility factors.MiR-133a may participate in the interaction of estrogen and EGFR pathway.(4)Tissue miR-25 and miR-133a may become biomarkers for metastasis and prognosis in female nonsmoking NSCLCs.