HUMAN DNA QUANTIFICATION IN THE STOOLS OF PATIENTS WITH COLORECTAL CANCER

Yolanda Teixeira, Jacqueline Miranda Lima, Maria Luiza Almeida Prado Oliveira Souza, Pedro Aguiar, Tiago Donizetti Silva, Nora Manoukian Forones

Background - Colorectal cancer is one of the main cause of cancer in the world. Colonoscopy is the best screen method, however the compliance is less than 50%. Quantification of human DNA (hDNA) in the feces may be a possible screen non-invasive method that is a consequence of the high proliferation and exfoliation of cancer cells. Objective - To quantify the human DNA in the stools of patients with colorectal cancer or polyps. Methods - Fifty patients with CRC, 26 polyps and 53 with normal colonoscopy were included. Total and human DNA were analyzed from the frozen stools. Results - An increased concentration of hDNA in the stools was observed in colorectal cancer patients compared to controls and polyps. Tumors localized in the left side of the colon had higher concentrations of hDNA. There were no difference between polyps and controls. A cut off of 0.87 ng/mL of human DNA was determined for colorectal cancer patients by the ROC curve, with a sensitivity of 66% and a specificity of 86.8%. For polyps the cut off was 0.41, the sensitivity was 41% and the specificity 77.4%. Conclusion - A higher concentration of hDNA had been found in colorectal cancer patients The quantification of hDNA from the stools can be a trial method for the diagnosis of colorectal cancer.