However, the expression of markers such as tyrosine hydroxylase and neuropeptide Y in rat DRG-derived ND sub-clones (Suburo et al., 1992), but not 50B11 cells (Chen et al., 2007) confirms that cell lines are derived from different types of nociceptive neurons or that certain properties exhibited by these clones were derived from the neuroblastoma parent cell. The gene discussed is NPY; the disease is Norrie disease.