Project Number: 1950-51520-008-09
Project Type: Reimbursable

Start Date: Aug 01, 2007
End Date: Sep 30, 2009

Objective:
To determine methylmalonic acid (MMA) in plasma from the Prostate, Lung, Ovarian and Colorectal Cancer Screening Trial(PLCO) participant for defining association between vitamin B12 status and colorectal cancer (CRC) risk.

Approach:
Use of LC/MS with isotope dilution method to determine plasma MMA concentrations. The role of B vitamins particularly folic acid as risk factors for colorectal cancers has been controversial. On one hand prospective data suggest that folic acid intake has a protective effect on CRC risk. More recent studies suggest that it actually increases the risk. The study here is from a nested case control study of CRC from participants in the PLCO. We have already been measuring folate, B12 homocysteine and B6. Determining MMA will provide information about people with normal B12 but functionally there are B12 deficient.