High endogenous USP3 protein expression was detected in total cellular protein from six MYCN-amplified (lanes 1–6), one MYCN overexpressing (lane 9), and two cMYC expressing cell lines (lanes 7 and 8; Fig. 6f), but not in three neuroblastoma cell lines without MYCN or cMYC expression or normal fibroblasts (lanes 10–13; Fig. 6f). This evidence concerns the gene MYCN and neuroblastoma.