血浆循环游离DNA浓度及完整性对肺癌和肺结核鉴别诊断的价值

Plasma cell-free DNA level and its integrity as biomarkers to distinguish lung cancer from tuberculosis

目的用实时荧光定量PCR(RT-PCR)检测肺癌、肺结核患者及健康人血浆循环游离DNA(cf-DNA)浓度及完整性,探讨其对肺癌和肺结核鉴别诊断的价值。方法收集49例肺结核患者、46例肺癌患者和47例健康对照者静脉血标本。用RT-PCR技术定量检测各组血浆cf-DNA中ALU115和ALU247浓度及完整性(ALU115/ALU247),化学发光微粒子免疫分析技术检测血浆糖链抗原(CA125)浓度;用Kruskal-Wallis H非参数检验比较总体差异,用Mann-Whitney U检验进行两两比较;绘制ROC曲线评价各项指标的诊断效能。结果肺结核组、肺癌组和健康人对照组间血浆cf-DNA中ALU115浓度(K-Wχ2=96.716,P=0.000)、ALU247浓度(K-Wχ2=25.228,P=0.000)、血浆cf-DNA完整性(K-Wχ2=75.283,P=0.000)差异均有统计学意义;肺结核患者较健康对照者血浆cf-DNA ALU115浓度(Z=-6.754,P=0.000)、ALU247浓度(Z=-4.570,P=0.000)和cf-DNA完整性(Z=-2.950,P=0.000)均升高;肺癌患者较健康对照者血浆cf-DNA ALU115浓度(Z=-8.245,P=0.000),ALU247浓度(Z=-4.088,P=0.000)和cf-DNA完整性(Z=-7.753,P=0.000)亦有明显升高;肺癌组较肺结核组血浆cf-DNA ALU115浓度(Z=-6.192,P=0.000)和cf-DNA完整性(Z=-7.753,P=0.000)均明显升高。肺癌组血浆cf-DNA ALU115浓度和cf-DNA完整性(ALU115/ALU247)的ROC曲线下面积(AUCROC)、敏感性、特异性分别0.931和0.934、100%和87%、72.9%和90.6%,均高于CA125(0.739,60.9%,86.5%),而ALU247(0.610,43.5%,79.2%)均低于CA125。结论RT-PCR检测血浆cf-DNA中ALU115和ALU247浓度及完整性可作为肺癌和肺结核辅助诊断的分子生物学指标。

Objective To detect the circulating cell-free DNA（ cf-DNA） level and its integrity in plasma of the patients with lung cancer or tuberculosis and healthy controls by real time PCR（ RT-PCR）,and evaluate their differential diagnosis value in lung cancer and tuberculosis. Methods Venous blood samples from 49 patients with tuberculosis,46 lung cancer patients and 47 healthy controls were collected. Plasma cf-DNA ALU115 and ALU247 levels and the integrity of cf-DNA（ reflected by ALU115 / ALU247） were determined by RT-PCR,and plasma carbohydrate antigen 125（ CA125） levels were detected by chemiluminescent microparticle immunoassay. The differences in different groups and between two groups were analyzed with Kruskal-Wallis H nonparametric test and MannWhitney U test,respectively. The diagnostic performances of plasma cf-DNA and its integrity and CA125 were evaluated by ROC curve. Results There were significant differences in plasma cf-DNA ALU115 and ALU247 levels and the integrity of cf-DNA among lung cancer,tuberculosis and healthy controls（ K-W χ^2= 96. 716,25. 228 and 75. 283,all P = 0. 000）. The plasma cf-DNA ALU115 and ALU247 levels and the integrity of cf-DNA in tuberculosis patients were significantly higher than those in healthy controls（ Z =- 6. 754,- 4. 570 and- 2. 950,all P = 0. 000）. The plasma cf-DNA ALU115 and ALU247 levels and the integrity of cfDNA in lung cancer patients were also significantly higher than those in healthy controls（ Z =- 8. 245,- 4. 088 and- 7. 753,all P= 0. 000）. The plasma cf-DNA ALU115 levels and the integrity of cf-DNA in lung cancer patients were significantly higher than those in tuberculosis patients（ Z =- 6. 192 and- 7. 753,both P = 0. 000）. The area under the ROC curve（ AUCROC）,sensitivity and specificity of plasma cf-DNA ALU115 level and the integrity of cf-DNA in lung cancer patients were 0. 931,100% and 72. 9% and0. 934,87% and 90. 6%,respectively,which were significantly higher than those of plasma CA125（ 0. 739,60. 9% and 86. 5%,P = 0. 000）,while the AUCROC,sensitivity and specificity of plasma cf-DNA ALU247 level（ 0. 610,43. 5% and 79. 2%） were below those of plasma CA125 level. Conclusion The circulating cf-DNA ALU115 and ALU247 levels in plasma and the integrity of cf-DNA detected by RT-PCR may be auxiliary biomarkers to diagnose lung cancer.