Role of Proteoglycans in Tumor Progression.

Data is now starting to accumulate on the differential expression of PGs in tumor cells of various invasive/metastatic potential. This is not so surprising if one considers the key functions that PGs play in the regulation of cell proliferation, adhesion and motility. However, characterization of PG expression in individual tumor types still awaits further detailed studies. Data on melanomas clearly indicate that PG phenotype is both specific and also promiscuous in a sense that ectopic expression of certain tissue specific PGs can occur in various tumors. Expression of a metastatic phenotype-specific splice variants of CD44 provides an example for the possible marker-function of PG. This also raises the hope that some PGs could be used as diagnostic/prognostic tools in pathology or even as a therapeutic targets against tumor dissemination. On the other hand, specific glycanation inhibitors may also be used for the modulation of tumor PG exist and the invasive phenotype.