ABSTRACT This application is being submitted in response to the Notice of Special Interest (NOSI) identified as NOT-CA-21-100. This proposal seeks to support Dr. Laura Stafman, a pediatric surgeon-scientist with both research and clinical interests in pediatric solid tumors. This proposal builds upon her previous basic science work while also deviating into the disparate field of metabolomics to allow her to establish herself as an independent surgeon-scientist. Neuroblastoma is the most common pediatric solid tumor outside the brain. It has a poor prognosis and for those who do survive, high morbidity. Those with high-risk disease have a survival rate around 50%. However, there is a subset of tumors that are more differentiated and occur in younger patients. Some of these require no treatment at all and either regress or differentiate into benign tumors spontaneously. These patients have been shown to express more differentiation genes. Within neuroblastoma there are varying degrees of differentiation; patients with undifferentiated disease have the worst prognosis. Treatment aimed to induce differentiation is used in neuroblastoma given its ability to progress cells from a stem cell-like state to a more mature, differentiated state. Cancer stem cells are a small subset of cells responsible for tumor initiation, recurrence, and drug resistance. Differentiation, stemness, and metabolism are all linked together as metabolism controls stemness and differentiation. If we can reprogram the cell metabolism from patients with undifferentiated neuroblastoma or cancer stem cells (poor prognosis) to behave more like the patients with low-risk disease (better prognosis), we may be able to more effectively treat neuroblastoma. It has been found that lipid metabolism in particular plays a role in differentiation in neuroblastoma. PIM1 is a kinase that has been shown to play a role in neuroblastoma differentiation as well; blocking PIM1 promotes differentiation. How this occurs is unknown, but PIM kinases play a role in lipid metabolism in non-cancer cells. Therefore, the goal of this project is twofold: 1) to determine the aspects of lipid metabolism affected by PIM1 and which of these regulates differentiation in neuroblastoma, and 2) to define the lipidomics landscape in neuroblastoma cancer stem cells to determine vulnerabilities in this subpopulation of cells responsible for relapse and recurrence. The findings hold promise for better understanding lipid metabolism in neuroblastoma in order to determine potential novel therapeutics to target high-risk neuroblastoma.