SOX2 and neoplasm: SiRNA knockdown of SOD2 expression significantly reduced mean TrkAIII SH-SY5Y tumour spheroid volume but, unlike GW441756, did not reduce Nanog, Nestin, SOX2 or CD117 expression in tumor spheroids, implicating SOD2 in the promotion of SH-SY5Y tumour spheroid growth and survival but not staminality.