Molecular recognition undoubtedly governs any aspect of cellular interaction. To understand tumor cell growth regulation and spread, analysisof protein carbohydrate interactions can contribute to lead to the establishment of rational methods for diagnosis and therapy. Chemically and biochemically optimized preparation of adequate tools, their application for localization of receptor (tissue lectin) and ligand (cellular glycoconjugate) pairs in tumor cells and tumor sections and the usefulness of a lectin from a plant extract as potent immunomodulator indicate the prospect for a place of such techniques in pathology and oncology.