In these challenging situations, immunohistochemical staining for glial fibrillary acidic protein and S100 protein may be helpful.[14] Moreover, Li demonstrated that the tumor cells expressed sex determining region Y-box 2 but not octamerbinding transcription factor 4 or homeobox protein Nanog homeobox in all GP specimens in their cases.[3]. The gene discussed is NANOG; the disease is neoplasm.