Comprehensive Analysis Of Clinical Pathological Features In Non-Small Cell Lung Cancer With EML4-ALK Fusion Gene Expression

Background and Objective:Lung cancer is one of the most common malignant tumor in our country.Non-small cell lung cancer(NSCLC)account for about 85%of lung cancer cases.In recent years,with the deepening understanding of the molcelar mechanism of carcinogenesis,high specificity,low toxicity of molecular targeted therapy play an important role in cancer treatment.The fusion gene of echinoderm microtubule associated protein-link 4(EML4)gene(5’end)and anaplastic lymphoma kinase(ALK)genes gene(3 ’end)can activate of ALK intracellular tyrosine kinase domain independently,tjen activata downstream pathways,including Ras/MEK/ERK pathway,PI3K/AKT pathway and JAK3/STAT3 pathway,which would led cells to abnormal proliferation and carcinogenesis.Recently the EML4-ALK fusion gene has become an important molecular target in treating NSCLC.The incidences of EML4-ALK fusion gene in NSCLC were about 2 to 11.6%,and the clinical characteristics and tumor histopathological subtype of these patients is still not very clear.So we hope to find clinicopathological and histopathological of NSCLC cases with EML4-ALK fusion gene,in order to make the proper therapeutic regimen of selecting EML4-ALK fusion gene targeted drugs for the clinical treatment.It was generally believed that EML4-ALK fusion gene and EGFR mutation molecular variation were exclusive.However,there are several reports recently about both EML4-ALK fusion gene and EGFR mutations appearing in some of NSCLC cases in the domestic and abroad.Therefore,it is significant clinical pathological features of these case with EML4-ALK fusion gene and EGFR mutation co-existence.This study examined the EML4-ALK fusion gene expressions and mucus nature in NSCLC tumor tissues,analyzing the gene-positive patients with EML4-ALK fusion of clinical features and and histopathological subtype and EGFR exon 21 mutation status.It discusses the role of the clinical pathological features in screening EML4-ALK fusion gene-positive patients,for or the rapid screening of the potential crowds of EML4-ALK rearrangement in and realization based on the genotyping of NSCLC individual molecular targeted therapy provides theoretical basis and reference.Methods:1.We collected 98 NSCLC cases which EGFR mutation in exon 21 by genetic testing.These cases are from Dalian Medical University Affiliated Hospital in 2007-2009 without radiotherapy and chemotherapy before operation.2.Immunohistochemistry method was used to detect the EML4-ALK fusion gene protein expression in NSCLC tumor tissues,analyzed the clinical pathological and histopathological features of EML4-ALK fusion gene-positive patients.3.AB-PAS staining was used to detect the mucus properties of NSCLC tumor tissues.4.Immunohistochemistry was used to detect the EGFR mutation in exon 21 to compare Immunohistochemistry with EGFR mutation with genetic testingResults:1.The relationship between the expressions of EML4-ALK fusion gene protein and clinical pathological features in NSCLC tumor tissues.The positive expression frequency of EML4-ALK fusion gene protein in NSCLC were 30.61%(30/98).The positive expression frequency of male patients in 16.36%(9/54),was significantly lower than that in female patients in 47.73%(21/44)(P<0.05);The positive expression frequency of adenocarcinoma in 39.06%(25/64)was significantly higher than that in squamous patients in 14.29%(4/28)(P<0.05).The expression of EML4-ALK fusion gene protein was not significantly correlated to the age,smoking history,tumor lymph node metastasis and differentiation.(P>0.05).2.The histologic pathological features in NSCLC tumor tissue with the expressions of EML4-ALK fusion gene proteinIn EML4-ALK fusion gene protein expression cases,the frequency of acinar predominant pattern was 39.58%(19/48),the frequency of papillary predominant pattern was 50.00%(3/6).that of other pattern adenocarcinoma was 30.00%(3/10).There was no significant difference between histological subtypes of lung adenocarcinoma(P>0.05).3.The relationship between the expressions of EML4-ALK fusion gene protein and Mucus nature in NSCLC tumor tissues.In 80 NSCLC cases AB-PAS staining,mucus secretion accounted for 41.25%(33/80).All of them are acidic mucus.EML4-ALK fusion gene-positive tumor cases mucus secretion accounted for 79.16%(19/24),EML4-ALK fusion gene negative tumors secrete mucus cases accounted for 25.00%(14/56),there was significant difference between them(P<0.05).4.The relationship between the expressions of EML4-ALK fusion gene protein and EGFR mutation in 21 exon in NSCLC tumor tissues.4.1 detected EGFR mutation in exon 21 with genetic testing and IHC were both positive in 13 cases,both negative in 55 cases,positive with genetic testing in 8 cases,only with IHC in 22 cases.The results of EGFR mutation detection were significant different between two methods(r=0.345,P<0.05).4.2 There are 5 cases that EML4-ALK fusion gene-positive patients carrying EGFR mutations in 21 exon,There are 20 cases that EML4-ALK fusion gene-positive patients do not carrying EGFR mutations in 21 exon,the number of EML4-ALK fusion gene-positive group carried with EGFR mutations in 21 exon is below than the EML4-ALK fusion gene-negative group,but not statistically significant(p>0.05).4.3 The case with co-existence of EML4-ALK fusion gene and EGFR mutation in 21 exon are women,non-smokers,acinar predominant adenocarcinoma.Four cases were detected by AB-PAS staining were all secreted acidic mucus intracellular and extracellular.Conclusion:1.EML4-ALK fusion gene expression is more common in women,adenocarcinoma NSCLC patients.The cases with EML4-ALK fusion gene have similar clinical pathological features with those with EGFR mutation in 21 exon.2.EML4-ALK fusion gene-positive tumor cells secrete Intracellular and extracellular acidic mucus at different levels.3.EML4-ALK fusion gene-positive patients usually do not carry EGFR mutations in exon 21,but there is few case with EML4-ALK fusion gene and EGFR exon 21 mutations co-existence.4.Those case with the co-existence of EML4-ALK fusion gene and EGFR mutation in 21 exon are women,non-smokers,acinar predominant adenocarcinoma with acidic mucus secretion.