ID4 and medulloblastoma: mRNA transcripts for Bdnf (Brain-derived neurotrophic factor), Neurl (Neuralized homolog), Id4 (Inhibitor of DNA binding 4), and Neurod2 (Neurogenic differentiation 2) were up-regulated 5, 3.7, 2.7, and 2.2-fold in SmoA1 +; Pten +/− medulloblastomas (Figure S2A).