Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, with a median survival of only 14 months after diagnosis, despite optimal surgery, chemotherapy, and radiation. Patients whose GBMs infiltrate the wall of the lateral ventricles (LV) have a substantially shorter survival than those whose tumors are located away from the LV, for reasons that remain unknown. Cerebrospinal fluid (CSF) in the LV can regulate the differentiation and migration of normal neural progenitor cells. We propose by analogy that LV-infiltrating GBMs also can interact with components of the CSF, and that this interaction makes these tumors more malignant. This proposal will study the interaction of human GBM cells and CSF. Particularly it will be focused on determining whether the osteopontin-CD44 axis plays a role in the response of GBM cells to CSF. This K01 award will allow Dr. Hugo Guerrero-Cazares to solidify his career as an independent scientist, develop bioinformatics and translational research skills and secure the preliminary information for a successful R01 grant application