血清游离DNA浓度及完整性在食管癌诊断中的价值

Value of the concentration and integrity of serum cell-free DNA for the clinical diagnosis of esophageal carcinoma

目的探讨血清游离DNA(cf-DNA)浓度及完整性在食管癌诊断中的价值。方法收集68例食管癌患者、36例食管良性病变患者和45例健康体检者的静脉血标本。采用基于Alu序列的实时荧光定量PCR法(Alu-qPCR)扩增重复短片段Alu115和长片段Alu247,检测血清cf-DNA浓度和完整性指数,血清DNA的总水平以Alu115的含量表示,完整性指数以Alu247/Alu115表示。采用化学发光法检测血清癌胚抗原(CEA)和鳞状细胞癌抗原(SCC)浓度。分析血清cf-DNA浓度和完整性指数与食管癌患者临床病理特征以及CEA和SCC的关系。采用受试者工作特征曲线(ROC)评价血清cf-DNA浓度、完整性指数、CEA和SCC的诊断效能。结果食管癌组、食管良性病变组、健康对照组血清Alu115的含量分别为1 162.0(817.8~1 652.4)、496.7(310.9~777.9)和432.3(198.4~634.1)ng/ml,Alu247/Alu115分别为0.57(0.51~0.65)、0.43(0.30~0.51)和0.42(0.33~0.48)。食管癌组血清Alu115含量和Alu247/Alu115均明显高于健康对照组和食管良性病变组(均P<0.01),食管良性病变组与健康对照组血清Alu115含量和Alu247/Alu115的差异无统计学意义(均P>0.05)。食管癌患者血清Alu115含量与患者年龄、性别、肿瘤分化程度、美国癌症联合委员会(AJCC)分期及有无淋巴结转移无关(均P>0.05),但Ⅲ期患者的血清Alu247/Alu115高于Ⅰ~Ⅱ期患者(P<0.05),Ⅳ期患者高于Ⅲ期患者(P<0.05)。食管癌患者血清Alu115含量与CEA和SCC的水平无关(均P>0.05),Alu247/Alu115与CEA和SCC的水平也无关(均P>0.05)。血清Alu115含量和Alu247/Alu115诊断食管癌的ROC曲线下面积分别为0.867和0.854,均高于CEA(0.622)和SCC(0.753),Alu115和Alu247/Alu115联合CEA和SCC检测时,诊断食管癌的灵敏度可分别提高到95.6%和94.1%。结论血清cf-DNA浓度和完整性检测有助于食管癌的早期辅助诊断和病程监测,对食管癌的诊断价值优于CEA和SCC。

ObjectiveTo explore the diagnostic value of serum cell-free DNA (cfDNA) concentration and integrity for esophageal carcinoma.MethodsVenous blood samples from 68 patients with esophageal cancer, 36 patients with benign esophageal lesions and 45 healthy subjects were collected. Circulating cfDNA was verified through quantitative real-time PCR (Alu-qPCR) using Alu-115 and Alu-247 primers. DNA integrity index was calculated as the ratio of Alu-qPCR results (Alu247/115). Concentrations of carcino-embryonic antigen (CEA) and squamous cell carcinoma associated antigen (SCC) were detected by chemiluminescence analyzer assay. Statistical analysis was performed using Mann-Whitney U test, Kruskal-Wallis H test and Spearman correlation test. The Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficiency of each index to esophageal carcinoma.ResultsThe median absolute serum Alu115 and the Alu247/115 index (1 162.0 ng/ml, 0.57) in esophageal cancer group were significantly higher than those in benign esophageal disease group (496.7 ng/ml, 0.43) and in healthy control group (432.3 ng/ml, 0.42) (all P<0.01, respectively). The Alu115 and Alu247/115 index of serum DNA in benign esophageal disease group were no statistically different from those in the healthy control group (all P>0.05, respectively). The levels of cfDNA and its integrity were not significantly correlated with age, gender, tumor differentiation, or disease stage according to American Joint Committee on Cancer (AJCC) staging system in the esophageal cancer group (all P>0.05). The serum Alu247/115 index of Stage Ⅲ patients was higher than that of Stage Ⅰ~Ⅱ patients(P<0.05). The serum Alu247/115 index of Stage Ⅳ was higher than that of Stage Ⅲ(P<0.05). In the esophageal cancer group, both of serum Alu115 and Alu247/115 index had no correlation with CEA or SCC (all P>0.05). The area under the ROC curve (AUC) of Alu115 and Alu247/115 index were 0.867 and 0.854, respectively, which were both higher than that of CEA (0.622) and SCC (0.753). The addition of Alu115 or Alu247/115 index to CEA and SCC detection increased the sensitivity of the diagnosis of esophageal cancer by 95.6% and 94.1%, respectively.ConclusionsThe detection of serum cfDNA concentration and integrity is helpful to the early diagnosis and monitoring of esophageal cancer. Their diagnostic value of esophageal cancer is better than that of the traditional tumor markers CEA and SCC.