The excised tumor tissue was sent to a board-certified pathologist for histopathological analysis and additional immunohistochemistry (IHC) testing, including markers for cytokeratin AE1/AE3, vimentin, oligodendrocyte transcription factor 2 (Olig2), and glial fibrillary acidic protein (GFAP). The gene discussed is OLIG2; the disease is neoplasm.