Tumors of the central nervous system affect 21 people per 100,000 every year, a figure that refers to countries with advanced economies, with an increase in incidence over time. Experimental evidence suggests that cancer stem cells (CSCs) may play a key role in the malignancy of these tumors. In fact, due to the hypoxic tumor microenvironment, these cells are able to create compensatory pathways that confer stem-like, angiogenic and pro-tumoral functions. Furthermore, it has been demonstrated that brain tumor stem cells are radio- and chemo-resistant and therefore not treatable with the therapeutic protocols currently in use. To date, in fact, there are no definitive treatments for the eradication of brain tumors. In this scenario, sphingolips, a class of lipid deputized to several physiological functions, are also involved in tumor onset, progression, drug resistance, and aggressiveness. In hypoxic tumor microenvironment, CSCs present a modified rheostat in the metabolism of sphingolipid, in favor of Sphingosine-1-phosphate (S1P). S1P is an intermediate of sphingolipid metabolism, formed from sphingosine through the action of sphingosine kinases (SK). Increasing evidence suggests that S1P acts as a tumor-promoting signal, predominantly in the extracellular environment, regulating important cellular properties correlated with tumor potential. The project aims to identify new molecular and metabolic targets involved in the survival and chemo-resistance of tumor stem cells in relation to the tumor microenvironment.