Multi-parametric flow cytometry of cells dissociated from paraspinal Nf1fl/fl;DhhCre PNF (Wu et al, 2008) or normal nerve/Dorsal root ganglia (DRG) (WT) showed that C5aR1 is expressed on nearly 40% of macrophages and 5–10% of dendritic cells in WT and PNF (of live CD45+ cells), and that the number of C5aR1+ cells increases in tumor largely because of the known increased numbers of immune cells in tumors and not an increase in C5aR1 protein on macrophages (Fig 1D–F). The gene discussed is PTPRC; the disease is neoplasm.