Different primers for diagnosing circulating cell-free DNA of colorectal cancer

BACKGROUND: Cell-free DNA (cfDNA) primers have been designed to screen for cancer diagnosis, but the results have been inconsistent. The study aimed to compare different primers for diagnosing cfDNA of colorectal cancer (CRC). METHODS: Peripheral blood specimens were collected from 71 patients with CRC and 20 patients with proliferative intestinal polyps. Quantitative polymerase chain reaction (q-PCR) was used to detect the concentration of cfDNA of these primers, including ALU elements (ALU), Beta-actin (ACTB), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The receiver operator characteristic curve (ROC) was performed to analyze the diagnostic value. RESULTS: The concentration of cfDNA in plasma of the CRC group determined by primers ALU and GAPDH was significantly higher than that of the intestinal polyp group (P<0.05). There was no significant difference in cfDNA level determined by primer ACTB between the CRC group and the intestinal polyp group (P>0.05). The area under curves (AUCs) of ALU, GAPDH, and ACTB were 0.734, 0.800, and 0.503, respectively. CONCLUSIONS: The GAPDH and ALU in plasma are expected to be sensitive indicators for the diagnosis of CRC.