Clinical relevance of cell-free DNA in gastrointestinal tract malignancy

// Yuan-Tzu Lan 1, 2 , Ming-Huang Chen 3, 6 , Wen-Liang Fang 2, 4 , Chih-Cheng Hsieh 5, 6 , Chien-Hsing Lin 7 , Fang-Yu Jhang 4 , Shung-Haur Yang 1, 2 , Jen-Kou Lin 1, 2 , Wei-Shone Chen 1, 2 , Jeng-Kai Jiang 1, 2 , Pei-Ching Lin 6, 8 , Shih-Ching Chang 1, 2 1 Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan 2 Department of Surgery, National Yang-Ming University, Taipei, Taiwan 3 Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan 4 Division of General Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan 5 Division of Thoracic Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan 6 School of Medicine, National Yang-Ming University, Taipei, Taiwan 7 Genome Research Center, National Yang-Ming University, Taipei City, Taiwan 8 Department of Clinical Pathology, Yang-Ming Branch, Taipei City Hospital, Taipei, Taiwan Correspondence to: Pei-Ching Lin, email: b7901127@tmu.edu.tw Shih-Ching Chang, email: changsc@vghtpe.gov.tw Keywords: cfDNA, GI tract cancer, biomarker, carcinoembryonic antigen, response Received: September 08, 2016      Accepted: November 30, 2016      Published: December 07, 2016 ABSTRACT Background: Cell-free DNA (cfDNA) extracted from blood has become a clinically feasible biomarker in various types of cancer. However, the clinical significance of cfDNA in gastrointestinal (GI) tract cancer among Asian populations requires further investigation. Results: The median cfDNA copy number was highest in esophageal cancer, followed by colorectal cancer and gastric cancer, which were all significantly higher than those of healthy individuals. The cfDNA levels were higher in GI tract cancer, followed by those in carcinoma in situ and then healthy individuals ( P = 0.019). During the postoperative surveillance, the cfDNA level tended to be more sensitive than the carcinoembryonic antigen level in predicting recurrence. For recurrent gastric cancer, a persistently high cfDNA level and an increasing trend was observed after surgery. For stage IV colorectal cancer, dynamic changes in the cfDNA level were correlated with the responses to chemotherapy and surgery. Materials and Methods: Blood samples were collected from 95 healthy individuals and from 855 patients diagnosed with GI tract malignancy, including 98 with esophageal cancer, 428 with stomach cancer, 329 with colorectal cancer and 30 with carcinoma in situ . The copy numbers of extracted cfDNA were analyzed and compared among the different types of GI cancers. Conclusions: The cfDNA level can serve as a feasible biomarker for detecting tumors in GI tract cancer. The cfDNA level may play a role in predicting tumor responses to chemotherapy and surgery in colorectal cancer; tumor recurrence should be considered in gastric cancer with a persistently high cfDNA level after surgery.