GLI1 and neoplasm: However, several distinguishing features can aid in the identification of GLI1-rearranged enteric tumors, such as the presence of a well-developed arborizing vascular network between the tumor nests, in conjunction with the lack of positive expression for myoepithelial markers, such as P63, glial fibrillary acidic protein (GFAP), and beta-catenin [1,13].