The present study explored the use of methylated NDRG4 gene as a candidate biomarker for diagnosis of colorectal cancer (CRC). Methylated NDRG4 gene expression from colorectal carcinoma tissue, paracarcinoma tissues, stools, blood and urine were detected successfully in DNA samples from 84 patients, by nested methylation-specific polymerase chain reaction and denaturing high-performance liquid chromatography. The sensitivity and specificity of methylated NDRG4 gene expression for us as a biomarker in colorectal cancer was analyzed and compared with 16 age-matched healthy controls. The positive detection rate of methylated NDRG4 was 81% in carcinoma tissue, 8.3% in paracarcinoma tissues, 54.8% in blood, 72.6% in urine and 76.2% in stools. Considering the convenience of the acquisition of urine samples, an additional group of 76 patients with CRC were recruited for verification of detecting methylated NDRG4 in the urine. The positive detection rate of methylated NDRG4 was 72.4% (55/76) in this cohort. The detection of methylated NDRG4 in stools and urine could be used as a novel diagnostic technique for highly sensitive and specific detection of CRC. Due to the ease of collecting urine samples, this novel method could be a potential biomarker for early diagnosis of CRC.
Keywords: NDRG4 methylation; blood; colorectal cancer; methylation-specific PCR; stools; urine.