Non-small Cell Lung Cancer With Plasma DAPK Gene Methylation Relations

Objective:This study was to investigate the expression of plasma free DNA tumor suppressor gene DAPK promoter methylation in non-small cell lung cancer (NSCLC), and to value the role of DAPK promoter methylation in carcinogenesis of non-small cell lung cancer.Methods:Methylation specific polymerase chain reaction (MSPCR) was used to detect the expression of plasma free DNA tumor suppressor gene DAPK promoter methylation in 61 non-small cell lung cancer patients. Of 61 cases of NSCLC,there were 38 cases of male,23 cases of female,35 cases of smokers,26 cases of non-smokers,29 cases of squamous carcinoma,32 cases of adenocarcinoma,18 cases of poorly differentiated,26 cases of moderately differentiated,17 cases of highly differentiated,39 cases with lymph node metastasis,22 cases without lymph node metastasis,15 cases of I stage,23 cases of II stage,30 cases of III stage,3 cases ofⅣstage (According to 2009, UICC TNM staging of lung cancer,7th edition). And there were 42 cases of healthy human plasma for comparison.Results:61 cases of healthy people were not detected in plasma DAPK gene methylation, and 42 cases of non-small cell lung cancer patients, a total of 18 cases detected DAPK gene methylation, the detection rate was 29.5%.There was statistical significance. (χ2=15.018 P=0.000 P<0.05) Male and female patients with detection rate were 23.7% and 39.1%, there was no significant difference(χ2=1.643 P= 0.200, P> 0.05). Smokers and non-smoking patients with positive rates were 34.1% and 26.9% respectively, no significant difference (χ2=0.146 P= 0.703, P> 0.05). In squamous cell carcinoma and adenocarcinoma, the positive rates were 31.0% and 28.1%, there was no significant difference (χ2=0.062 P= 0.804, P> 0.05). In poorly differentiated, moderately differentiated, highly differentiated, the detection rate were 44.4%,34.6% and 11.8%, And there was no statistical significance(χ2=4.608 P=0.100, P> 0.05). Patients with lymph node metastasis detection rate 35.9% without lymph node metastasis detection rate of 18.2% of patients, and there was statistical significance (χ2=4.961 P= 0.026, P<0.05).ⅠⅡ,ⅢandⅣstage patients detection rate were 20.0%,13.0%,50.0% and 66.7% respectively, and there was statistical significance (χ2=9.678 P= 0.022, P<0.05). There is no neural invasion and neural invasion in patients with detection rate were 33.3% and 25.8%, there was no significant difference (χ2=0.415 P= 0.519, P> 0.05). With vascular invasion and no vascular invasion in patients with detection rate was 32.1% and 27.3% respectively, no significant difference (χ2=0.173 P= 0.678, P> 0.05). DAPK gene promoter methylation and gender non-small cell lung cancer, smoking or not, the degree of tumor differentiation, neural invasion and vascular invasion were not related, but with the lymph node metastases and staging of patients.Conclusion:1.Not detected in healthy people DAPK gene promoter methylation, but in some non-small cell lung cancer was detected, so DAPK gene promoter methylation and non-small cell lung cancer occurrence are related.2. DAPK gene promoter methylation and non-small cell lung cancer of the lymph node metastasis and the clinical stages have correlation; it may be used as the assessment of non-small cell lung cancer staging the molecular biology of index.