As it is known that C3a plays its biological role by engaging the C3a receptor (C3aR), we then examined C3aR expression on TAAs and MB tumor cells isolated from Math1-Cre/Ptch1loxp/loxp MB, as well as primary astrocytes derived from the normal cerebellum of WT neonatal mice by conventional PCR and qPCR. The gene discussed is C3AR1; the disease is neoplasm.