B vitamins, such as folate, vitamin B6, and vitamin B12, play an important role as coenzymes in one-carbon metabolism and may affect colorectal cancer risk. We aimed to comprehensively investigate the relationships of plasma folate, pyridoxal-5'-phosphate (PLP, the active form of vitamin B6), vitamin B12, methylmalonic acid, homocysteine, and cysteine with colorectal cancer risk, accounting for suspected modifiers (alcohol intake, MTHFR C677T genotype, and plasma C-reactive protein) and potential confounders. We conducted a case-control study nested within the Multiethnic Cohort study and analyzed prospectively collected blood samples from 224 incident colorectal cancer cases and 411 controls matched on age, sex, race/ethnicity, study site, date/time of blood draw, and hours of fasting. We found an inverse association between plasma PLP levels and colorectal cancer, with odds ratios (95

作者：Lo?c, Le Marchand；Kami K, White；Abraham M Y, Nomura；Lynne R, Wilkens；Jacob S, Selhub；Maarit, Tiirikainen；Marc T, Goodman；Suzanne P, Murphy；Brian E, Henderson；Laurence N, Kolonel

来源：Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology 2009 年 18卷 8期