All patients with ALL, patients with osteosarcoma (n = 6/7), and all patients with medulloblastoma showed reduced CP and/or AP functionality at several time points following chemotherapy, whereas patients with Ewing sarcoma or germ cell tumors had no significant reduction in complement activation upon treatment for their solid tumor (Figure 4). The gene discussed is DHCR7-DT; the disease is Ewing sarcoma.