Quantification and clinical value of cell-free circulating DNA in colorectal cancer

Background and objectives: Development of a non-invasive sensitive and specific biomarker is the upmost importance in early detection of cancers. Colorectal cancer (CRC) as the second leading cause of cancer worldwide is not excluded from this fact. Circulating nucleic acids including cell-free circulating DNA (cfcDNA) in patients with cancers have been recognized as promising biomarkers for diagnosis, prognosis and treatment. This study aimed to quantify cfcDNA in CRC to evaluate its potential value as a non-invasive blood-based source for investigating biomarker candidates.Methods: Total DNAs were extracted from plasma samples of 62 patients with stages II, III and IV CRC and 24 healthy controls. The quality and quantity of DNA were studied by spectrophotometry. Quantification of baseline cfcDNA was determined as the amount of free GAPDH in plasma, by using real-time quantitative polymerase chain reaction (RT-qPCR). Results: RT-qPCR data revealed that the concentration of cfcDNA in CRC patients was significantly different from healthy controls (P<0.05). Further analysis showed that the concentrations of cfcDNA were correlated with the degree of differentiation (r=0.87, P<0.05) and tumor size (r=0.72, P<0.05) but not with other clinicopathological factors.Conclusion: The significantly elevated plasma DNA level in CRC was shown to be correlated with clinicoplathological features. In conclusion, cfcDNA could be served as a suitable source of molecular biomarkers which can benefit to clinical settings of CRC. Hence, gene analysis of cfcDNA might be at the forefront of advance in personalized medicine, particularly for cancer early detection and management.

Keywords:

Biomarker , cell-free circulating DNA , Colorectal cancer