[Endogenous lectins in tumors and their possible importance in the diagnosis and therapy of cancers].

The oncological application of knowledge of biological recognition processes offers opportunities to favorably translate results from basic science into clinical procedures within tumor diagnosis and therapy. Based on the attractive assumption that biological information can be stored in a glycobiological code within the sugar chains of cellular glycoconjugates, the specific interaction of proteins and carbohydrates warrants special attention. Lectins form a particular class of carbohydrate-binding proteins, separated from sugar-specific enzymes as well as antibodies. They are expressed by normal cells, but also, remarkably, by tumor cells. The pattern of lectin expression can be recorded by routine histopathological procedures using labelled carriers that have been chemically modified by defined coupling of the histochemically crucial carbohydrate moieties. The tumor-associated differences, documented by application of these neoglycoproteins, serve as guidelines for consequently following biochemical studies and for lectin-mediated drug targeting. Increased selectivity of drug delivery by using tailor-made neoglycoproteins as transport vehicles may result from specifically aiming at lectins as cellular targets for binding of the 'Trojan horse'. Besides these aspects of tumor lectinology the assumption of the noteworthy significance of protein-carbohydrate recognition may also contribute to progress in a challenging as well as complex problem in tumor research, the formation of metastases. Joint approaches with chemical, biochemical, cell biological, histochemical and oncological techniques will allow to critically assess the value of tumor lectinology for oncology.