WILL NEOADJUVANT CHEMOTHERAPY AFFECT THE CAPACITY OF HEAD AND NECK SQUAMOUS-CELL CARCINOMA TO BIND NEOGLYCOPROTEINS

Evidence is growing that the carbohydrate portion of glycoconjugates i s not merely an inert structural addition to the protein or lipid back ground, but is involved in normal and altered physiological processes. Conjugation of the potentially bioactive carbohydrate ligand to an in ert labeled carrier generates the tools to histochemically monitor the presence of sugar receptors like lectins in tissue sections. In head and neck squamous cell carcinoma endogenous lectins have been systemat ically characterized by a selected panel of conjugates of such synthet ic probes. In this investigation we provide evidence that the antineop lastic agents carboplatin and 5-fluorouracil influence the expression of carbohydrate-binding receptors. In cases with a statistically signi ficant alteration, an increasing loss of binding capacity from treatme nt cycle to cycle was observed in cytoplasmic areas. This means that t he extent of binding of beta-N-acetyl-galactosamine, cellobiose, galac tose, and sialic acid was affected. The pattern of diminished binding capacity in nuclear structures encompassed beta-N-acetyl-galactosamine , beta-N-acetyl-glucosamine, sialic acid as carbohydrate part of the n eoglycoprotein. Thus, exposure to certain chemotherapeutic agents clea rly influences the capacity of tumor cells to mediate protein-carbohyd rate interactions. Concomitant with the elucidation of the functions o f such an interplay the significance of this down-regulation will be a pparent.