The expression levels of complement proteins C1QA, C1QB, and C1QC are negatively correlated with osteosarcoma patient prognosis, and these three genes are associated with tumor immune infiltration [138] To determine immune-related genes that can forecast the prognosis of osteosarcoma, Mingde Cao et al. collected 864 immune-related genes from literature [139], and eventually constructed a prognosis model using four genes (APBB1IP, FKBP11, GJA5 and NPC2). The gene discussed is NPC2; the disease is osteosarcoma.