A Tumor-Related Vitamin B₁₂ Binding Protein in Adolescent Hepatoma

Extraordinary elevations of serum vitamin B₁₂ content and serum levels of vitamin B₁₂ binding protein were found in three young patients with hepatoma. All had normal white-cell counts and no evidence of megaloblastosis. Despite a superficial resemblance to the alterations of vitamin B₁₂ and vitamin B₁₂ binders observed in chronic myeloid leukemia, the vitamin B₁₂ binding protein in hepatoma serum exhibited distinct and unique properties that suggest a novel, tumor-related protein. (N Engl J Med 289:1053–1056, 1973).