Correlation Between EGFR And ALK Mutation And TTF-1 Expression In Lung Adenocarcinoma

Background and AimsLung cancer is the most common cause of cancer related mortality worldwide and the treatment of lung cancer also bring huge economic burden.From the Epidemiological Studies,we know smoking environmental pollution and genetic are major factors attributing to the development of lung cancer.According to the classification by WHO,lung cancer was divided into non-small cell lung cancer(NSCLC)and small cell lung cancer(SCLC)on the basis of treatment effect,prognosis and biological property.As much as 80-85%of the histological type of lung cancer is NSCLC,which contains adenocarcinoma and squamous carcinoma.However,the majoity of patients with lung cancer are diagnosed with advanced or metastatic disease and therefore do not undergo surgical procedures,with median overall survival time for 1 year and 5-year survival rate less than 16%.Early detection,early diagnosis,and early treatment are essential for the improvement of prognosis and survival time.In recent years,mutations in epidermal growth factor receptor(EGFR)and anaplastic lymphoma kinase(ALK)gene have been identified as oncogenic drivers of ADC with potential predictive value for targeted therapies.Selected patients treated with respective inhibitors have a significantly improved outcome compared with standard chemotherapy and even with longer survival.With the clinical application of molecule-targeted drugs,we recommend driving gene detection before the molecule-targeted treatment.At present,the usually detection methods of EGFR include sequencing,PCR-SSCP,mutant-enriched PCR,ARMS,micro fluidics digital PCR,HRM,DHPLC,and so on.There are three main menthods in detecting ALK mutation,which are fluorescent in situ hybridization(FISH),reverse transcription-polymerase chain reaction(RT-PCR)and immunohistochemistry(IHC).But the gene detection is expensive,and takes a long time.In addition,it has a certain requirement for the laboratory and the operator.For the sake of save medical resources rationally and select people who with high positive rate of EGFR and ALK.We conduct this study to investigate the correlation between epidermal growth factor receptor(EGFR)and anaplastic lymphoma kinase(ALK)mutation and thyroid transcription factor-1(TTF-1)expression in lung adenocarcinoma,Whether TTF-1 is a useful predictor of EGFR and ALK mutation.Methods242 cases of lung adenocarcinoma were collected from the Department of Oncology and Respiration during 2016.01 to 2017.05.Immunohistochemistry was used to detect the expression of TTF-1 and the mutation of ALK,ARMS was used to detect EGFR mutation.Furthermore,the relationship between EGFR and ALK mutation and TTF-1 expression were also analysed.P<0.05 was identified assignificant statistical.ResultIn TTF-1 positive patients,79 cases EGFR mutation and 23 cases ALK mutation were found.In TTF-1 negative patients,2 cases EGFR mutation and 0 case ALK mutation were detected.The mutation rate of EGFR in TTF-1 positive cases was higher than in negative cases(46.75%VS 8%),the difference was statistically significant(P<0.001);the mutation rate of ALK in TTF-1 positive cases was also higher than that in negative cases(11.68%VS 0%),but the difference was no statistically significant(P>0.05).The negative predictive value of TTF-1 to EGFR and ALK mutation were 92%and 100%.Conelusion:EGFR and ALK mutation are exceptionally rare in TTF-1 negative lung adenocarcinoma.For patients with TTF-1 negative who are temporarily unable to obtain genetic testing results,chemotherapy can be carried out first,and then the gene status should be identified as much as possible in subsequent treatment.