OLIG2 and mixed neuronal-glial tumor: Three subtypes of GNTs that demonstrate Olig2 upregulation are dysembryoplastic neuroepithelial tumors (DNTs; Komori and Arai, 2013; Matsumura et al., 2013), papillary glioneuronal tumors (PGNTs; Tanaka et al., 2005; Chen et al., 2006; Gelpi et al., 2007; Iżycka-Świeszewska et al., 2008; Matsumura et al., 2013), and rosette-forming glioneuronal tumors (Wang et al., 2009; Luan et al., 2010; Xiong et al., 2012; Matsumura et al., 2014).