Serum folate, LINE-1 hypomethylation, and overall survival in a prospective cohort of hepatocellular carcinoma patients.

Abstract

4101 Background: Folate plays a central role in DNA methylation reactions, but the relationship between folate and methylation status has not been studied in HCC patients. We hypothesized that low folate levels would correlate with global hypomethylation, and worsened survival in HCC patients. Methods: 72 newly-diagnosed HCC patients were enrolled in a prospective study, beginning 10/08, and followed until 9/11. We excluded those with previous malignancy, and uncompensated Child Pugh (CP) B or C disease. We used pyrosequencing to evaluate quartiles of LINE-1 methylation in plasma as a surrogate for global tumor hypomethylation. We evaluated the relationship between folate deficiency (serum folate levels < 6ng/mL), DNA hypomethylation (LINE-1 methylation < 25th percentile i.e., < 69.4%), and overall survival in our cohort. Results: Median age was 60; 82% were men and 67% had hepatitis C. Mean serum folate levels were 12.1 ng/mL (SD = 5.3 ng/mL), while mean % LINE-1 methylation was 69.9 (SD = 4.6). In a univariate analysis, folate deficiency and LINE-1 hypomethylation were significant predictors of poor overall survival (HR = 3.77; 95% CI: 1.37, 10.41, and HR=3.50; 95% CI: 1.51, 8.13, respectively). These markers remained independent predictors of survival in a multivariate model including age, CP class, AJCC stage and AFP. HR for folate deficiency in this model was 3.52 (95% CI: 1.16, 10.70), and HR for LINE-1 hypomethylation was 2.74 (95% CI: 1.10, 6.85). We also found a significant association between folate deficiency and LINE-1 hypomethylation (p = 0.04). Conclusions: We provide novel data that folate deficiency is an independent predictor of worsened overall survival in patients with HCC in a multivariate model. Further, we show that global changes in DNA methylation assesed in plasma correlate with folate levels, supporting a possible mechanistic link between the two. Folate supplementation, and the use of other agents which modulate methylation, deserve further study in HCC.