Moreover, a common genetic change in ALT cancers and cell lines is a loss-of-function mutation in ATRX (Heaphy et al., 2011a; Bower et al., 2012; Jiao et al., 2012; Lovejoy et al., 2012), which is normally a constitutive component of PML NBs (Xue et al., 2003; Bieniasz, 2004). Here, GPT is linked to cancer.