Sikora Katarzyna, Bedin Chiara, Vicentini Caterina, Malpeli Giorgio, D'Angelo Edoardo, Sperandio Nicola, Lawlor Rita T, Bassi Claudio, Tortora Giampaolo, Nitti Donato, Agostini Marco, Fassan Matteo, Scarpa Aldo
ARC-NET Research Centre, University of Verona, Verona - Italy.
Int J Biol Markers. 2015 Feb 24;30(1):e136-41. doi: 10.5301/jbm.5000088.
Currently, no reliable blood-based assay for early detection of pancreatic ductal adenocarcinoma (PDAC) is available. Cell-free DNA (cfDNA) quantitation in patients' plasma has been recently applied in monitoring several cancer types. This study evaluates the diagnostic potential of cfDNA in PDAC patients.
Plasma cfDNA levels and integrity ratio were assayed using quantitative real-time PCR of Alu-repeat amplicons in patients with pancreatic ductal adenocarcinoma (n=50), pancreatic neuroendocrine tumor (n=23), and chronic pancreatitis (n=20), as well as in healthy volunteers without evidence of pancreatic disease (n=23).
The total load of cfDNA, obtained by Alu83 quantitation, was the highest in PDAC patients than in any of the other patient groups (Welch t test; p<0.001) and was an average predictor of PDAC disease (AUC=0.664; CI, 0.56-0.77). A nonlinear association between Alu83 levels and subjects' age was detected (Spearman's rho=0.35; p<0.001) in the overall population, as well as within the PDAC patients' group (Spearman's rho=0.47; p<0.001). Necrosis-derived cfDNA fragments, quantitated with the Alu244 amplicon, were barely detectable in any of the samples and, in that respect, comparable between the different subject groups. CfDNA integrity estimation (Alu244/Alu83 ratio) was significantly affected by the limited detectability of plasma Alu244 levels.
The lack of detectable levels of necrosis-derived cfDNA in pancreatic pathologies considerably affects the clinical use of such biomarker in PDAC patients. Different methods of analysis should be applied in the evaluation of the cfDNA diagnostic value in pancreas pathology.
目前，尚无用于早期检测胰腺导管腺癌（PDAC）的可靠血液检测方法。患者血浆中的游离DNA（cfDNA）定量分析最近已应用于多种癌症类型的监测。本研究评估了cfDNA在PDAC患者中的诊断潜力。
采用Alu重复序列扩增子的定量实时PCR法检测胰腺导管腺癌患者（n = 50）、胰腺神经内分泌肿瘤患者（n = 23）、慢性胰腺炎患者（n = 20）以及无胰腺疾病证据的健康志愿者（n = 23）的血浆cfDNA水平和完整性比率。
通过Alu83定量获得的cfDNA总负荷在PDAC患者中高于其他任何患者组（韦尔奇t检验；p<0.001），是PDAC疾病的一个平均预测指标（AUC = 0.664；CI，0.56 - 0.77）。在总体人群以及PDAC患者组中均检测到Alu83水平与受试者年龄之间存在非线性关联（斯皮尔曼等级相关系数rho = 0.35；p<0.001）（斯皮尔曼等级相关系数rho = 0.47；p<0.001）。用Alu244扩增子定量的坏死来源的cfDNA片段在任何样本中几乎都检测不到，在这方面，不同受试者组之间具有可比性。血浆Alu244水平的有限可检测性显著影响了cfDNA完整性评估（Alu244 / Alu83比率）。
胰腺疾病中坏死来源的cfDNA缺乏可检测水平，这在很大程度上影响了这种生物标志物在PDAC患者中的临床应用。在评估胰腺疾病中cfDNA的诊断价值时应采用不同的分析方法。
