Alu-based cell-free DNA: a novel biomarker for screening of gastric cancer

// Chen Qian 1, * , Shaoqing Ju 1, 2, * , Jing Qi 2, * , Jianmei Zhao 3 , Xianjuan Shen 2 , Rongrong Jing 1 , Juan Yu 1 , Li Li 1 , Yingjuan Shi 1 , Lurong Zhang 4 , Zhiwei Wang 5 and Hui Cong 1 1 Center of Laboratory Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, China 2 Surgical Comprehensive Laboratory, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, China 3 Department of Pediatrics, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, China 4 Department of Radiation Oncology, UF Shands Cancer Center, University of Florida, Gainesville, FL 32610, USA 5 Department of General Surgery, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, China * These authors contributed equally to this work Correspondence to: Hui Cong, email: huicjs@163.com Keywords: branched DNA assay, cell-free DNA, Alu sequence, gastric cancer, serum Received: January 18, 2016      Accepted: July 18, 2016      Published: August 05, 2016 ABSTRACT Gastric cancer (GC) is the fourth most common cancer and the second major cause of cancer-related deaths worldwide. In our previous study, a novel and sensitive method for quantifying cell-free DNA (CFD) in human blood was established and tested for its ability to predict patients with tumor. We want to investigate CFD expression in the sera of GC patients in an attempt to explore the clinical significance of CFD in improving the early screening of GC and monitoring GC progression by the branched DNA (bDNA)-based Alu assay. The concentration of CFD was quantitated by bDNA-based Alu assay. CEA, CA19-9, C72-4 and CA50 concentrations were determined by ABBOTT ARCHITECT I2000 SR. We found the CFD concentrations have significant differences between GC patients, benign gastric disease (BGD) patients and healthy controls ( P < 0.05). CFD were weakly correlated with CEA ( r = −0.197, P < 0.05) or CA50 ( r = 0.206, P < 0.05), and no correlation with CA19-9 ( r = −0.061, P > 0.05) or CA72-4 ( r = 0.011, P > 0.05). In addition, CFD concentrations were significantly higher in stage I GC patients than BGD patients and healthy controls ( P < 0.05), but there was no significant difference in CEA, CA19-9 and CA50 among the three traditional tumor markers ( P > 0.05). Our analysis showed that CFD was more sensitive than CEA, CA19-9, CA72-4 or CA50 in early screening of GC. Compared with CEA, CA19-9, CA72-4 and CA50, CFD may prove to be a better biomarker for the screening of GC, thus providing a sensitive biomarker for screening and monitoring progression of GC.