TY - JOUR
T1 - The relationship between gene-specific DNA methylation in leukocytes and normal colorectal mucosa in subjects with and without colorectal tumors
AU - Ally, Mina Sarah
AU - Al-Ghnaniem, Reyad
AU - Pufulete, Maria
PY - 2009
Y1 - 2009
N2 - CpG island methylation in the promoter regions of tumor suppressor genes has been shown to occur in normal colonic tissue and can distinguish between subjects with and without colorectal neoplasms. It is unclear whether this relationship exists in other tissues such as blood. We report the relationship between estrogen receptor gene (estrogen receptor alpha) methylation in leukocyte and normal colonic tissue DNA in subjects with and without colorectal neoplasia. DNA was extracted from frozen stored whole blood samples of 27 subjects with cancer, 30 with adenoma, 16 with hyperplastic polyps, and 57 disease-free subjects. DNA methylation in seven CpG sites close to the transcription start of estrogen receptor alpha was quantitated using pyrosequencing and expressed as a methylation index (average methylation across all CpG sites analyzed). Estrogen receptor alpha methylation in leukocyte DNA was compared with estrogen receptor alpha methylation in normal colonic mucosa DNA that had been previously determined in the same subjects. Estrogen receptor alpha was partially methylated (median, 4.3%; range, 0.0-12.6%) in leukocyte DNA in all subjects, with no significant difference between disease groups (P>0.05). Estrogen receptor alpha methylation in leukocytes was 60% lower than estrogen receptor alpha methylation in normal colonic tissue (P
AB - CpG island methylation in the promoter regions of tumor suppressor genes has been shown to occur in normal colonic tissue and can distinguish between subjects with and without colorectal neoplasms. It is unclear whether this relationship exists in other tissues such as blood. We report the relationship between estrogen receptor gene (estrogen receptor alpha) methylation in leukocyte and normal colonic tissue DNA in subjects with and without colorectal neoplasia. DNA was extracted from frozen stored whole blood samples of 27 subjects with cancer, 30 with adenoma, 16 with hyperplastic polyps, and 57 disease-free subjects. DNA methylation in seven CpG sites close to the transcription start of estrogen receptor alpha was quantitated using pyrosequencing and expressed as a methylation index (average methylation across all CpG sites analyzed). Estrogen receptor alpha methylation in leukocyte DNA was compared with estrogen receptor alpha methylation in normal colonic mucosa DNA that had been previously determined in the same subjects. Estrogen receptor alpha was partially methylated (median, 4.3%; range, 0.0-12.6%) in leukocyte DNA in all subjects, with no significant difference between disease groups (P>0.05). Estrogen receptor alpha methylation in leukocytes was 60% lower than estrogen receptor alpha methylation in normal colonic tissue (P
U2 - 10.1158/1055-9965.EPI-08-0703
DO - 10.1158/1055-9965.EPI-08-0703
M3 - Article (Academic Journal)
C2 - 19258481
SN - 1055-9965
VL - 18
SP - 922
EP - 928
JO - Cancer Epidemiology, Biomarkers and Prevention
JF - Cancer Epidemiology, Biomarkers and Prevention
IS - 3
ER -