Clinical value of quantification for cell-free DNA in plasma of colorectal cancer patients

Abstract

Objective To determine the diagnostic and prognostic value of quantitative estimates of cell-free DNA (cfDNA) in coloretal cancer (CRC). Methods The study included 178 patients at different stages of CRC and 56 healthy donors. The plasma cfDNA was determined using real-time quantitative polymerase chain reaction(Real-time PCR) amplification of the β-actin gene (99 bp). Receiver operating characteristic (ROC) curve was applied to analyze the diagnostic value of cfDNA level. The patients of stage Ⅳ were followed up to determine the prognostic value of cfDNA. Results The cfDNA levels were higher in CRC patients than those in health controls [(63.07±65.38) vs. (22.85±8.88) ng/ml, P=0.000]. The cfDNA levels were also higher in CRC patients of Ⅲ-Ⅳ stage than those in health controls [(39.59±31.56) and (107.32±102.85) ng/ml vs. (22.85±8.88) ng/ml, P=0.000 for all]. Association was observed among plasma cfDNA level and histologic grading [(29.42±18.29), (54.69±75.05), (9.67±103.18) ng/ml, P=0.000] as well as TNM stage (P=0.000). Survival analysis confirmed that high cfDNA levels were clear indicators of a poor over survival. Conclusion This study shows that the baseline cfDNA levels in plasma of CRC patients has no value in the early diagnosis of CRC, but is an effective prognosis biomarker. Key words: Colorectal cancer; Cell-free DNA; Real-time quantitative polymerase chain reaction