ABO and lip and oral cavity carcinoma: In subjects with blood group O, vWF is cleared more quickly, resulting in approximately 25% lower levels of circulating vWF than in subjects with blood groups A or B. Therefore, the differing glycosyltransferase activity resulting from the A alleles is biologically relevant to a disease outcome (i.e., VTE) and seems to be directly related to the efficiency of glycosyl group transfer to a target molecule (i.e., vWF) which we believe further implicates ABO glycosyltransferase activity even in the pathogenesis of oral cancer.