MYCN and neoplasm: Further comparison of the tumor models via a differential gene expression analysis also revealed that Cdkn2a and Cdkn2b were both among the top 10 significantly upregulated genes in GTML as compared to GMYC (Fig. 4d), suggesting putatively different roles of these tumor suppressors, including ARF, in MYC- and MYCN-driven Group 3 MBs.