DNA methylotype analysis in colorectal cancer

  • Authors:
    • Jinsheng Yu
    • Robert R. Freimuth
    • Robert Culverhouse
    • Sharon Marsh
    • Mark A. Watson
    • Howard L. McLeod
  • View Affiliations

  • Published online on: October 1, 2008     https://doi.org/10.3892/or_00000092
  • Pages: 921-927
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Abstract

The methylation status of a gene promoter is considered to be an important mechanism for the development of many tumors, including colorectal cancer. Recent studies have shown that specific patterns of DNA methylation across multiple CpG loci in some human tumors are more informative than the detection of one single CpG locus in tumor genomes. In the present study, multiple CpG methylations of three genes (CDKN2A, DPYD and MLH1) were detected in DNA samples from patients with colorectal cancer using Pyrosequencing® technology. The bisulfite-converted DNA was amplified with a nested PCR and five or six CpG loci of each gene were assessed to determine DNA methylotype. Our data showed that 10/49 (20.4%), 6/48 (12.5%) and 14/49 (28.6%) of tumors were methylated with a DNA methylation level >0.2 in CDKN2A, DPYD and MLH1, respectively. Our study indicated a similar DNA methylation level across the multiple CpG loci for all three genes in the methylated tumor DNA samples, demonstrating a dichotomous trait in DNA methylation. The tumor DNA samples had unique DNA methylation patterns, which were high-degree and multiple-site methylation, but the normal DNA samples had no or a low-degree and dispersed single-site methylation. In addition, an inverse correlation in those methylated tumors was observed between DNA methylation and RNA expression for MLH1 (RS=−0.62, P=0.003), but not for CDKN2A and DPYD. In conclusion, distinctive DNA methylotypes exist in colorectal cancer and may depict a distinct biology in apparently homogeneous tumors.

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October 2008
Volume 20 Issue 4

Print ISSN: 1021-335X
Online ISSN:1791-2431

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Spandidos Publications style
Yu J, Freimuth RR, Culverhouse R, Marsh S, Watson MA and McLeod HL: DNA methylotype analysis in colorectal cancer. Oncol Rep 20: 921-927, 2008.
APA
Yu, J., Freimuth, R.R., Culverhouse, R., Marsh, S., Watson, M.A., & McLeod, H.L. (2008). DNA methylotype analysis in colorectal cancer. Oncology Reports, 20, 921-927. https://doi.org/10.3892/or_00000092
MLA
Yu, J., Freimuth, R. R., Culverhouse, R., Marsh, S., Watson, M. A., McLeod, H. L."DNA methylotype analysis in colorectal cancer". Oncology Reports 20.4 (2008): 921-927.
Chicago
Yu, J., Freimuth, R. R., Culverhouse, R., Marsh, S., Watson, M. A., McLeod, H. L."DNA methylotype analysis in colorectal cancer". Oncology Reports 20, no. 4 (2008): 921-927. https://doi.org/10.3892/or_00000092