The ABH blood group determinants are carbohydrates found in different human cells and tissues. The modulation in their expression in the course of ontogenesis, as well as the studies on their subcellular localization, impose a discussion on the role of ABH antigens as molecules participating in cell interactions, contact inhibition, adhesion and metastases. It is supposed that they are also involved in cellular differentiation during human embryogenesis. The described association between blood groups and disease and the de novo acquisition of blood group determinants support the idea that ABH antigens are related to pathological processes. The modulation in blood group antigen expression observed in several tumors demands a clarification of their diagnostic and prognostic value as tumor-associated markers.
Biomedical Reviews 1994; 10: 55-63.