3-HAAO and quinolinate phosphoribosyltransferase (QPRT) mRNA has been shown to be expressed constitutively and after IFN-γ stimulation in the neuroblastoma cell line, SK-N-SH, with both enzyme levels being slightly higher in SK-N-SH compared with controls, primary neurons, although not significantly [30]. The gene discussed is IFNG; the disease is neuroblastoma.