Associations between genetic variation in one-carbon metabolism and LINE-1 DNA methylation in histologically normal breast tissues

作者：Llanos Adana A M; Marian Catalin; Brasky Theodore M; Dumitrescu Ramona G; Liu Zhenhua; Mason Joel B; Makambi Kepher H; Spear Scott L; Kallakury Bhaskar V S; Freudenheim Jo L; Shields Peter G

来源：Epigenetics, 2015, 10(8): 727-735.

DOI：10.1080/15592294.2015.1062205

• breast tissues
• folate
• genome-wide methylation
• LINE-1 methylation
• one-carbon metabolism

Genome-wide DNA hypomethylation is an early event in the carcinogenic process. Percent methylation of long interspersed nucleotide element-1 (LINE-1) is a biomarker of genome-wide methylation and is a potential biomarker for breast cancer. Understanding factors associated with percent LINE-1 DNA methylation in histologically normal tissues could provide insight into early stages of carcinogenesis. In a cross-sectional study of 121 healthy women with no prior history of cancer who underwent reduction mammoplasty, we examined associations between plasma and breast folate, genetic variation in one-carbon metabolism, and percent LINE-1 methylation using multivariable regression models (adjusting for race, oral contraceptive use, and alcohol use). Results are expressed as the ratio of LINE-1 methylation relative to that of the referent group, with the corresponding 95% confidence intervals (CI). We found no significant associations between plasma or breast folate and percent LINE-1 methylation. Variation in MTHFR, MTR, and MTRR were significantly associated with percent LINE-1 methylation. Variant allele carriers of MTHFR A1289C had 4% lower LINE-1 methylation (Ratio 0.96, 95% CI 0.93-0.98), while variant allele carriers of MTR A2756G (Ratio 1.03, 95% CI 1.01-1.06) and MTRR A66G (Ratio 1.03, 95% CI 1.01-1.06) had 3% higher LINE-1 methylation, compared to those carrying the more common genotypes of these SNPs. DNA methylation of LINE-1 elements in histologically normal breast tissues is influenced by polymorphisms in genes in the one-carbon metabolism pathway. Future studies are needed to investigate the sociodemographic, environmental and additional genetic determinants of DNA methylation in breast tissues and the impact on breast cancer susceptibility.

• 出版日期2015-8-3
• 单位rutgers