Therefore, comparing the proportion of cells positive for surface ChAT staining (66 ± 1%) with those positive for total ChAT staining (79 ± 3%) indicates that a major fraction of ChAT protein in SH-SY5Y neuroblastoma cells is localized extracellularly (compare dot plots in Figure 1 vs. Figure 2). The gene discussed is CHAT; the disease is neuroblastoma.