Expression Of C-myc And Caspase-8in Human Non-small-cell Lung Cancer And Its Clinical Significance Study

1Background and objectiveLung cancer is the leading cause of cancer death worldwide, estimates that8.3million people will die from smoking related diseases in2030, including lung cancer,accounts for3.1%. More than80%lung cancer is non-small cell lung cancer(NSCLC),5years survival rate less than10%. Because of high incidence rates andlow survival rates, it is important to study pathogenesis that may help prevent thedisease from developing. Global cancer researchers consensus: carry out positive andeffective screening, early diagnosis, early treatment, early intervention to reducemorbidity, mortality, and improve curative ratio.The occurrence of tumor is the result of environmental factors and geneticfactors, affected by multiple factors, involving multiple genes, performing a verycomplicated process.Tumor appear closely related to cell apoptosis, gene levelinduce apoptosis gene inactivation, inhibit excessive expression of apoptosis gene, isan important reason of tumor occurrence. Studies have shown that the change ofapoptosis related with tumor prognosis. Inducing tumor cell apoptosis is an importantpart in tumor treatment strategy. With the continuous development of molecularbiology technology and improvement of cancer pathogenesis deepening, gene therapyhas become great prospects for the development of highly efficient, specific andtargeted therapy following chemotherapy, radiotherapy, surgery. The study of apoptosis gene c-myc have showed in domestic and foreignliterature, but the expression of caspase-8in malignant tumor cells and its relationshipwith cell apoptosis research is relatively lack, less research in NSCLC. This researchmainly studies the expression and clinical significance of c-myc, and caspase-8inNSCLC and relationship of the two. The study of c-myc and caspase-8will provideexperimental basis for clinical diagnosis and treatment.2Study Object and Methods2.1Study objectSpecimen (study group) were collected from NSCLC patients operated in thehoracic surgery resection of the first affiliated hospital of zhengzhou university from2010to2012, total example is50, all patients confirmed by pathologists, have notperformed any anti-tumor therapy. According to AJCC and UICC, comparison groupis20cases adjacent normal lung tissue (away from cancer edge more than3cm). Allspecimens are embeded in paraffin, cut slices by pathological professionals, NSCLCtissue and normal tissue cut each3copies.2.2MethodsTesting the expression of c-myc, caspase-8in NSCLC and normal tissueadjacent to carcinoma by immune histochemical method (S-P method), detectingapoptosis by TUNEL method.2.3Assessing resultc-myc, caspase-8positive standard: c–myc in lung squamous carcinoma mainlyexpress in nucleus, in adenocarcinoma mainly express in cytoplasm, positiveexpression is characterized by tan particles. caspase–8express in cytoplasm and (or)nuclei appear tan particles.The expression of c-myc, caspase-8in non-small celljudged in two ways:①staining degree: no dyeing is0points, light yellow is1point,lighe yellow to tan is2points, tan is three points.②Dyeing cell percentage: underlight microscopy (400times), each view count100cells, each section selected10 vision randomly, calculate positive cells take up of cancer cells,<10%is0points,10%to25%is1point,26%-50%is2points,51%or highe is three points. Twoquantitative Numbers together, Negative result is total value less than4, greater orequal to4is positive.Cell apoptosist detected by TUNEL method after processing, using opticalmicroscope400times and combining with apoptotic cell whose nucleus dyed tan,count every1000apoptotic cells for statistical analysis. Apoptosis index (AI)=apoptosis cells r/total cells.2.4Statistical processingALL experimental data are processed by spss17.0software.The expression ofc-myc and caspase-8and their relationship with clinical pathological characteristics inNSCLC by matching the four-layer table card square test; the correlation of c-mycand caspase-8in NSCLC apply data correlation analysis; the relationship betweenc-myc, caspase-8and apoptosis analyzed by linear correlation analysis.α=0.05.3Result3.1The expression of c-myc in NSCLC and its relationship with clinical andpathological featuresAfter immunohistochemical, the expression of c-myc is mainly located in cellcytoplasm and (or) cell nuclei dyed tan, the positive rate of50cases lung cancer is60.0%(30/50), the positive rate20cases normal tissue adjacent to carcinoma is20%(4/20) and the difference is statistically significance (χ2=9.150, P=0.002), butthe staining of c-myc in cancerous tissue were deeper than normal tissue adjacent tocarcinoma. According to the results, the expression rate of c-myc in adenocarcinoma(78.3%) is higher than in squamous cell carcinomas (44.4%) and the difference wasstatistically significance (χ2=5.918, P=0.015). High differentiation of positiveexpression rate (88.9%), differentiation (65.4%) and low differentiation (33.3%), thethree difference was statistically significance (χ2=7.888, P=0.019). Positive rate oflymph node metastasis (75%) is higher than without lymph node metastasis (46.2%), the difference was statistically significance (χ2=4.327, P=0.038). TNM staging Ⅲand Ⅳ positive rate (84.2%) is higher than stage Ⅰ and Ⅱ positive rate (45.1%) andthe difference was statistically significance (χ2=7.484, P=0.006). The expression ofc-myc has no obvious relation with gender, age, smoking, tumor size, tumor growthposition and pleural effusion (P>0.05).3.2The expression of caspase–8in NSCLC and its relationship with clinicaland pathological featuresAfter immunohistochemical, the expression of caspase-8is mainly located incell nucleus and (or) cytoplasmwas dyed tan, the positive rate of50cases lung canceris62.0%(31/50), the positive rate of20cases normal tissue adjacent to carcinoma is65%(13/20), there is no statistically significance difference between the two (χ2=0.055, P=0.814). Results show that lymph node metastasis positive rate (79.2%) ishigher than no lymph node metastasis (46.2%) and the difference was statisticallysignificance (χ2=5.773, P=0.016). TNM Ⅲ, Ⅳpositive rate (84.2%) is higher thanstage Ⅰ and Ⅱpositive rate (48.4%) and the difference was statistically significance(χ2=6.417, P=0.011). The expression of caspase-8has no obvious relation withgender, age, pathological type, differentiation degree, smoking, tumor size, tumorlocation and pleural effusion (P>0.05).3.3The correlation analysis of caspase–8and c-myc in NSCLC tissuec-myc is proto-oncogenes, involved in apoptosis.caspase-8is apoptosis geneeffects,with other apoptosis related gene mediated lung cancer apoptosis.Experimental results in non-small cell lung cancer tissues, c-myc positive30casesand caspase-8positive31cases, both positive expression19cases, c-myc negative20cases, caspase-8negative19cases, both express negative8cases.There is no obviouscorrelation between c-myc and caspase-8analyzed by correlation analysis of paireddata.(r=0.034, P=0.812) 3.4The relationship between c-myc, caspase-8and apoptosisc-myc integral and apoptotic index AI are negatively correlated (r=-0.784,P=0.000), caspase-8integral and apoptotic index AI are positively correlated(r=0.885, P=0.000).4Conclision1．c-myc related to the occurrence,development, clinical stage, malignantdegree of NSCLC.2．caspase-8closely associated with the development, metastasis of NSCLC.3．Cut or inhibit the expression of c-myc inhibits the development of NSCLC;Repair caspase-8gene expression could inhibit the development of NSCLC.