LEVEL OF CIRCULATING CELL-FREE DNA IN THE SERUM OF EGYPTIAN PATIENTS AS A BIOMARKER FOR DIAGNOSIS AND PROGNOSTIC PREDICTION OF COLORECTAL CANCER

M. Elnadry*, Y. F. Alkelany, Amin M. Hegazy, A. A. Mahmoud and A. M. Abdel-Naby

ABSTRACT

Background: There is a small amount of circulating DNA in the plasma of healthy individuals. Elevated circulating levels of DNA are related to many diseases and their characteristics such as cancer, pregnancy, autoimmune disease, myocardial infarction, trauma and so on. Aim of the study: To evaluate the level of circulating cell-free DNA as a serum biomarkers in diagnosis and progression of colorectal cancer (CRC) operated and non-operated Egyptian patients. Patient and Methods A case control study was carried out from the periods at July 2015 to December 2016 The study included 90 persons who fulfilling the designed inclusion criteria were classified into four groups, Group I included 30 patients with colorectal cancer (pre-operative), Group II included 30 patients with colorectal cancer (post-operative), Group III included 15 patients with colorectal polyps, and Group IV included 15 healthy volunteers as control group, All participant after detailed history and clinical examination were subjected to routine laboratory investigation, imaging study, endoscopic assessment and serum evaluation of the serum level of circulating cell-free DNA and Carcin-Embryonic Antigen (CEA). Results: The mean DNA concentration was 2.46 μg/ml, 0.519 μg/ml 1.684 μg/ml and 1.068 μg/ml for CRC (pre-operative), CRC (post-operative), colorectal polyps and healthy controls participant respectively. DNA concentration was significantly higher in CRC (pre-operative) patients compared with healthy controls (P =0.05). The sensitivity, specificity, positive and negative predictive values of DNA concentration were 36.7% and 100%, 100% and 50.5% respectively which was of value in distinguishing CRC patients from healthy controls. As regard to progression of DNA level the serum concentration in G II was significantly decreased (0.519 ng/dl) versus its level in GI (2.46 ng/dl) p =0.01. Regarding to level of CEA, the results showed that there was decrease in its level in G II (60.03 ng/dl) versus its level in GI g 84.95 ng/dl (p=0.001). Conclusion: Level of circulating cell-free DNA could be clinically used as a tool for diagnosis, and follow-up of CRC patients and in discriminating such patients from healthy subjects or patients with benign colonic lesions.

Keywords: Circulating cell free DNA , CRC.