Circulating cell-free DNA in serum as a biomarker of colorectal cancer

Aims The aim of this study was to report circulating cell-free DNA using ALU247 and ALU247/ALU115 biomarkers in serum of operated and non-operated patients with colorectal cancer (CRC). Methods To undertake this, 90 blood samples were collected, including 30 samples from healthy volunteers; 27 samples from CRC non-operated patients and 33 samples from CRC-operated patients. Circulating cell-free DNA was verified through quantitative real-time PCR (qPCR) using ALU115 and ALU247 primers. Results With regard to the ALU115-qPCR biomarker, the increased levels of circulating cell-free DNA in serum of non-operated patients were significant when compared with control (p<0.05). Moreover, levels of ALU247-qPCR biomarker were statistically significant between non-operated versus operated and non-operated versus control groups (p=0.000). With regard to the ALU247/115-qPCR biomarker, significant differences were observed between control versus non-operated patients (p=0.019), operated versus non-operated patients (p=0.005) and control versus operated patients (p=0.043). Conclusions Thus, the ALU247 and ALU247/ALU115-qPCR biomarkers may be important in detecting and monitoring CRC patients in both early and late stages.