The fact that heparan sulfate is so widely distributed and evolutionarily conserved is a testament to the vital importance of this molecule in cell development and functions such as cell proliferation, migration, adhesion, differentiation and angiogenesis. During remodelling of the extracellular matrix, heparan sulfate cleavage by heparanase results in the release of glycosaminoglycan-anchored bioactive molecules which is one of the major interests when investigating cell signalling pathways mediated by heparanase in different physiological states (non neoplastic, tumor and inflammatory cells). The aim of my research is mainly to study and understand the regulatory proccess of glycosaminoglycans biosynthesis and to develop novel inhibitory for the endo-beta-glucuronidase heparanase. Heparanase is the only mammalian enzyme involved in heparan sulfate degradation in vivo. The selection of specific peptides using a phage display technology, potentially targeting the pro-adhesion activity of enzyme or other cell signalling pathways, rather than only enzymatic activity could be important to understand how heparanse is involved in carcinogenesis and also to better understand the role of heparan sulfate.