Our research focuses on the control cell polarization and migration in heath and disease and more specifically on the mechanisms regulating astrocyte migration and glioblastoma invasion. Polarity is a critical parameter in most cellular functions including cell division, cell differentiation, cell division and cell migration. Loss of polarity is a all-mark of cancer cells, suggesting that alteration of polarity signaling is a key step in oncogenesis. Our aim is to characterize the molecular mechanisms controlling cell polarity during migration in normal cells and to identify molecular alterations responsible for the loss of polarity and abnormal migratory behavior. We compare the directed collective migration of normal astrocytes with the invasion of glioblastoma cells. Astrocytes are major glial cells of the central nervous system. They fulfill a wide variety of functions allowing neurons to develop, survive and function correctly. In a normal adult brain, astrocytes are essentially immobile and do not display any obvious polarized morphology. Under pathological situations involving inflammation of the cerebral tissue, astrocytes become reactive and polarize and migrate in a collective manner in the direction of the inflammatory site. In these conditions, cell polarization and migration are tightly regulated by the extracellular environment. Astrocytes or their precursors can give rise to very invasive tumors called gliomas. Gliomas correspond to the majority of primary brain tumors and are associated with very poor prognosis. The most aggressive gliomas, called glioblastomas, are amongst the most invasive tumor. The capacity glioblastoma cells to escape the initial tumor and migrate over long distance allow them to escape to classical therapeutic treatments.