Elevated Vitamin B12 Levels in Myeloproliferative Neoplasm (MPN) Patients: A Potential Diagnostic and Prognostic Marker.

Abstract

Background: Elevated vitamin B12 (B12) levels are linked to an increased risk of cancers, including hematological malignancies. This study focuses on the relationship between elevated B12 and myeloproliferative neoplasms (MPNs): Polycythemia Vera (PV), Primary Myelofibrosis (MF), Essential Thrombocytosis (ET), and Chronic Myeloid Leukemia (CML). Elevated B12 in MPNs is believed to arise from increased transcobalamin I (TCI) secretion by proliferating leukocytes, leading to higher serum levels. B12 may serve as a diagnostic and prognostic biomarker for these conditions. However, its sensitivity, specificity, and cutoff levels are unclear.

Aim: To assess the prevalence of high B12 levels in MPN patients, determine the median levels, identify a diagnostic cutoff, and evaluate the sensitivity and specificity of B12 as a marker.

Methods: Data were retrieved from the National Center for Cancer Care and Research in Doha, Qatar, for MPN patients from January 2016 to December 2022.

Results: A total of 467 patients were included: 232 with CML, 98 with PV, 88 with ET, and 50 with MF. The majority were male (66%) and of Asian origin (56%), with a median age of 48.7 years. CBC results showed median hemoglobin of 9.2 g/dL, WBC count of 73 x 10^3/uL, and platelet count of 531 x 10^3/uL. Elevated B12 levels were found in 95 patients (20%): 71% CML, 14% PV, 10% MF, and 5% ET. Extreme elevations were seen in 59 patients. The mean B12 level decreased from 747.3 ± 686.5 pg/mL before treatment to 397.9 ± 343.7 pg/mL after one year (p=0.01). Median levels were 458 pg/mL (718) before treatment and 301 pg/mL (229) after. In the extreme high B12 group, the mean was 1722 pg/mL before and 677 pg/mL after treatment.

Conclusion: Elevated B12 levels are associated with disease activity in CML. However, their role as a reliable marker for disease monitoring remains uncertain, and further studies are needed to confirm their utility for CML progression.