Person:

Harris, Holly R.

Folate, methionine, vitamin B6, and vitamin B12 may influence carcinogenesis due to their roles in the one-carbon metabolism pathway which is critical for DNA synthesis, methylation, and repair. Low intake of these nutrients has been associated with an increased risk of breast, colon, and endometrial cancers. Previous studies that have examined the relation between these nutrients and ovarian cancer risk have been inconsistent and have had limited power to examine the relation by histologic subtype. We investigated the association between folate, methionine, vitamin B6, vitamin B12, and alcohol among 1910 women with ovarian cancer and 1989 controls from a case-control study conducted in eastern Massachusetts and New Hampshire from 1992 to 2008. Diet was assessed via food frequency questionnaire. Participants were asked to recall diet one-year before diagnosis or interview. Logistic regression models were used to calculate odds ratios (OR) and 95% confidence intervals (95% CIs). We also examined whether the associations varied by ovarian cancer histologies using polytomous logistic regression. We observed an inverse association between dietary vitamin B6 (covariate-adjusted OR=0.76, 95% CI 0.64–0.92; ptrend=0.002) and methionine intake (covariate-adjusted OR=0.72, 95% CI=0.60–0.87; ptrend<0.001) and ovarian cancer risk comparing the highest to lowest quartile. The association with dietary vitamin B6 was strongest for serous borderline (covariate-adjusted OR=0.49, 95% CI=0.32–0.77; ptrend=0.001) and serous invasive (covariate-adjusted OR=0.74, 95% CI=0.58–0.94; ptrend=0.012) subtypes. Overall, we observed no significant association between folate and ovarian cancer risk. One-carbon metabolism related nutrients, especially vitamin B6 and methionine, may lower ovarian cancer risk.

Telomeres are repetitive non-coding DNA sequences at the ends of chromosomes that provide protection against chromosomal instability. Telomere length and stability are influenced by proteins, including telomerase which is partially encoded by the TERT gene. Genetic variation in the TERT gene is associated with ovarian cancer risk, and predicts survival in lung cancer and glioma. We investigated whether genetic variation in five telomere maintenance genes was associated with survival among 1480 cases of invasive epithelial ovarian cancer in the population-based New England Case-Control Study. Cox proportional hazard models were used to calculate hazard ratios and 95% confidence intervals. Overall we observed no significant associations between SNPs in telomere maintenance genes and mortality using a significance threshold of p=0.001. However, we observed some suggestive associations in subgroup analyses. Future studies with larger populations may further our understanding of what role telomeres play in ovarian cancer survival.