MYCN and neoplasm: Pseudorosettes and tumor ‘islands’ separated by septae are characteristic of human neuroblastoma21 and although NXS2 and 9464D showed some evidence of these structures, (Fig. 1C,D), these features were more common in the TH-MYCN tumors (Fig. 1E), which were found to have a very similar histological structure to human neuroblastoma.