GDNF and Mobius syndrome: Among the most upregulated genes were those pertinent to tumor progression, including the signature genes for G3 MBs (e.g., NRL, NR2E3, and RORB)3,26 and candidate MYC-targeted genes (e.g., RPL21, CAV3, GDNF, GPR27, TIMP3, and SLC35G2)27 (Fig. 3a, b).