Glioblastoma is the most common primary brain tumor in adults and one of the most aggressive cancers with a poor life expectancy even with the best available therapies. Our inability to cure glioblastoma patients reflects the need for greater understanding of the disease, both in terms of differences between patients as well as differences among cancer cells in one patient. One subpopulation, called tumor initiating cells, has the ability to initiate tumors in animal models when transplanted. These same cells are also called cancer stem cells because they have some pathways and properties that are similar to normal (non-cancerous) stem cells. Tumor initiating cells/cancer stem cells are suggested to maintain tumor growth in many ways. These include increasing the formation of blood vessels to feed a growing tumor and by surviving chemo- and radiotherapies. Our laboratory seeks to identify the ways that brain tumor initiating cells maintain tumor growth and understand how this is different than other tumor cells or non-cancerous cells. We know that certain conditions within a tumor, called microenvironments, are more likely to promote brain tumor initiating cell behaviors. We are therefore working to better understand the interaction between tumor microenvironments, brain tumor initiating cells, and therapeutic resistance. We believe that these studies will identify new signals in the tumor that can then be blocked with drugs, leading to better therapies to control tumor growth and decrease the side effects of current approaches. Ultimately, we hope to increase patient survival and quality of life.