Arendt JFH, et al. - Given the reported link between elevated vitamin B12 levels (B12) and increased short-term cancer risk, researchers assessed the implications for early cancer detection in primary care. They used The Health Improvement Network primary care database, UK, to identify subjects with plasma B12 measurements. Subjects with low B12 levels—as well as those with cancer or B12 treatment prior to date of B12 measurement—were excluded from the study. The investigators used Read codes to detect incident cancer, which was the outcome of interest. Overall, 757,185 individuals met inclusion criteria. Higher 1-year cancer risk was observed in relation to elevated plasma B12 levels vs normal B12 levels in this study population, indicating that B12 metabolism could be influenced by some cancer types. Among those with elevated B12 levels, higher risks were noted, especially for liver cancer, pancreas cancer, and myeloid malignancies.