NANOG and neoplasm: The possibility that TrkAIII may not only maintain SH-SY5Y cells in an undifferentiated state but may also promote staminality was supported by the reduction of Nanog, Nestin and SOX2 mRNA expression in TrkAIII SH-SY5Y tumour spheroids following incubation with the specific TrkA tyrosine kinase inhibitor GW441756 [51].