GP9 and neuroblastoma: In particular, among these validated proteins, we specifically selected 13 membrane proteins that were significantly upregulated in neuroblastoma, including PGLYRP2, GP9, SLC44A1, STX7, PARVB, PTPRJ, SLC16A1, ITGB3, BSG, SLC43A3, ITGA2B, MIA3 and APLP1, as well as a typical neuroblastoma marker CHGA, while the remaining 32 proteins were selected randomly (Supplementary Table 6).