A study investigated whether alcohol and dietary folate intakes were associated with promoter methylation in clear-cell renal cell carcinoma (ccRCC).
The Netherlands Cohort Study with a case-cohort design included 120,852 subjects aged 55-69 yr in 1986. Diet was measured with a food-frequency questionnaire. After 20.3 yr of follow-up, paraffinembedded tumor blocks were collected. Methylationspecific polymerase chain reaction (MSP) was used to analyse promoter methylation of 11 genes. ccRCC cases were classified into low (0-19% of the genes), intermediate (20-39%), and high (40%+) methylation. Multivariable Cox regression analyses were conducted, stratified according to methylation, including 3,980 subcohort members and 297 ccRCC cases.
Increasing alcohol intake was associated with decreased ccRCC risk, but this was not statistically significant; multivariable adjusted hazard ratio (HR) for ≥30 g alcohol/day versus 0 g/day was 0.78 [95% confidence interval (CI): 0.48-1.24], and P-value for trend was 0.46. In strata according to methylation index, no significant heterogeneity was observed. Dietary folate intake was not associated with ccRCC risk. There was no significant heterogeneity between strata according to methylation index. There was no effect modification of alcohol and dietary folate intake on ccRCC risk, nor in strata according to methylation index.
The findings do not support the hypothesis that alcohol and dietary folate intakes are involved in clear-cell renal cell carcinoma.
Source: Alcohol and Dietary Folate Intake and Promoter CpG Island Methylation in Clear-Cell Renal Cell Cancer. Schouten LJ, Deckers IA, van den Brandt PA, Baldewijns MM, van Engeland M. Nutr Cancer. 2016 Jun 24:1-11. [Epub ahead of print]