Based on mRNA (Fig. 6a) and protein expression levels (Fig. 6b, c), the examined neuroblastoma cell lines could be characterized as either HTR3Ahigh (SH-SY5Y, CHLA-15, and CHLA-20), expressing markedly high levels of HTR3A, or HTR3Alow (NBL-28, NBL-38, and NBL-40), with only weak HTR3A expression. The gene discussed is HTR3A; the disease is neuroblastoma.