DNA methylation analysis of SFRP2, GATA4/5, NDRG4 and VIM for the detection of colorectal cancer in fecal DNA

Abstract

Aberrantly methylated genes are increasingly being established as biomarkers for the detection of colorectal cancer (CRC). In the present study, the methylation levels of the secreted frizzled-related protein gene 2 (SFRP2), GATA binding protein 4/5 (GATA4/5), N-Myc downstream-regulated gene 4 (NDRG4) and vimentin (VIM) promoters were evaluated for their use as markers in the noninvasive detection of CRC. Methylation-specific polymerase chain reaction was performed to analyze promoter CpG methylation of SFRP2, GATA4/5, NDRG4 and VIM in the fecal DNA of 56 patients with CRC and 40 individuals exhibiting normal colonoscopy results. Promoter methylation levels of SFRP2, GATA4/5, NDRG4 and VIM in CRC patients were 57.1% (32/56), 42.9% (24/56), 83.9% (47/56), 28.6% (16/56) and 41.1% (23/56), respectively. Furthermore, the specificity of the genes were 90.0% (4/40), 95.0% (2/40), 82.5% (7/40), 97.5% (4/40) and 85.0% (6/40), respectively. The overall sensitivity of detection for fecal DNA with at least one methylated gene was 96.4% (54/56) in CRC patients. By contrast, only 14 of the 40 normal individuals exhibited methylated DNA in the aforementioned promoter regions. Methylation of the SFRP2, GATA4/5, NDRG4 and VIM promoters in fecal DNA is associated with the presence of colorectal tumors. Therefore, the detection of aberrantly methylated DNA in fecal samples may present a promising, noninvasive screening method for CRC.

Keywords: colorectal cancer; fecal DNA; methylated DNA.

Figure 1

Methylation of SFRP2, GATA4/5, NDRG4 and VIM in fecal DNA obtained from colorectal cancer patients and controls, as shown by methylation-specific polymerase chain reaction using primers for methylated and unmethylated alleles of bisulfite-modified DNA. SFRP2, secreted frizzled-related protein 2; GATA4/5, GATA binding protein 4/5; VIM, vimentin; NDRG4, N-Myc downstream-regulated gene 4; M, methylated; U, unmethylated; N, normal samples; C, colorectal cancer samples.

Figure 2

Prevalence of hypermethylated SFRP2, GATA4/5, NDRG4 and VIM in stool samples from CRC patients and normal controls. CRC, colorectal cancer; SFRP2, secreted frizzled-related protein 2; GATA4/5, GATA binding protein 4/5; NDRG4, N-Myc downstream-regulated gene 4; VIM, vimentin.