Recently, two genome-wide association studies have suggested that single nucleotide polymorphisms at the ABO gene locus are associated with two serum markers, namely tumor necrosis factor-α (TNF-α) and soluble intracellular adhesion molecule-1 (sICAM-1).33,34 TNF-α is an inflammatory cytokine that affects tumor progression. This evidence concerns the gene TNF and neoplasm.