%0 Journal Article
%T Associations between Intake of Folate, Methionine, and Vitamins B-12, B-6 and Prostate Cancer Risk in American Veterans
%A Adriana C. Vidal
%A Delores J. Grant
%A Christina D. Williams
%A Elizabeth Masko
%A Emma H. Allott
%A Kathryn Shuler
%A Megan McPhail
%A Alexis Gaines
%A Elizabeth Calloway
%A Leah Gerber
%A Jen-Tsan Chi
%A Stephen J. Freedland
%A Cathrine Hoyo
%J Journal of Cancer Epidemiology
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/957467
%X Prostate cancer (PC) is the second leading cause of cancer death in men. Recent reports suggest that excess of nutrients involved in the one-carbon metabolism pathway increases PC risk; however, empirical data are lacking. Veteran American men (272 controls and 144 PC cases) who attended the Durham Veteran American Medical Center between 2004每2009 were enrolled into a case-control study. Intake of folate, vitamin B12, B6, and methionine were measured using a food frequency questionnaire. Regression models were used to evaluate the association among one-carbon cycle nutrients, MTHFR genetic variants, and prostate cancer. Higher dietary methionine intake was associated with PC risk (OR = 2.1; 95%CI 1.1每3.9) The risk was most pronounced in men with Gleason sum <7 (OR = 2.75; 95%CI 1.32每 5.73). The association of higher methionine intake and PC risk was only apparent in men who carried at least one MTHFR A1298C allele (OR = 6 . 7 ; 95%CI = 1.6每27.8), compared to MTHFR A1298A noncarrier men (OR = 0 . 9 ; 95%CI = 0.24每3.92) (p-interaction = 0 . 0 4 5 ). There was no evidence for associations between B vitamins (folate, B12, and B6) and PC risk. Our results suggest that carrying the MTHFR A1298C variants modifies the association between high methionine intake and PC risk. Larger studies are required to validate these findings. 1. Introduction Prostate cancer (PC) is the most commonly diagnosed malignancy in men, and the second leading cause of cancer death in men globally [1]. Age adjusted PC incidence and mortality exhibits considerable geographic and racial variation, suggesting that both heritable and environmentally acquired/dietary factors are important [2, 3]. Regarding dietary factors, either deficiencies or excesses of nutrients involved in the one-carbon metabolism pathway have been hypothesized to increase PC risk, but findings are inconsistent [4每15]. The one-carbon cycle is necessary for both cellular proliferation and epigenetic modification and folate is a critical component of this pathway. Folate functions as an important source of carbon moieties in the synthesis of nucleotides that are essential for DNA repair and replication. The important role of folate is illustrated by the mutations and chromosomal damage associated with its deficiency. These effects are central to the efficacy of antifolate chemotherapeutic agents (e.g., methotrexate) as tumor therapeutics. Folate is also essential in the conversion of methionine to its derivative, S-adenosylmethionine, the principal methyl donor [16], which transfers methyl groups to molecules key for
%U http://www.hindawi.com/journals/jce/2012/957467/