IDH1 and neoplasm: Mutations of IDH1 and IDH2 in combination with microenvironmental effects in certain tumor types are likely the driver mutations that are responsible for the malignant phenotype, rather than simply epiphenomena (Dang et al., 2009; Figueroa et al., 2010; Xu et al., 2011; Koivunen et al., 2012; Losman et al., 2013).