PARP1 and Ewing sarcoma: By considering expression changes in a pathway context, we identified additional candidate glioblastoma genes, such as the putative cell adhesion gene ITGBL1 [67], the orphan nuclear receptor NR0B1, which is strongly upregulated in G179 and is known to be upregulated and mediate tumor growth in Ewing's sarcoma [68], and the genes PARP3 and PARP12, which belong to the poly(ADP-ribose) polymerase (PARP) family of ADP-ribosyl transferase genes involved in DNA repair (Table 4).