Proposed pathways of tumorigenesis include loss of Merlin-mediated inhibition of the MAP kinase MEK/ERK cascade, abnormalities in the PI3K/mTOR pathway, interactions between vascular endothelial growth factor (VEGF) secreted by schwannoma cells and endothelial cells, and KRIT1 gene mutations [5,6]. This evidence concerns the gene KRIT1 and schwannoma.