Data and methods 1. Clinical data: From April 1, 2011, the Multidisciplinary Collaborative Group of Pediatric Oncology of Xinhua Hospital started the individualized molecular target detection program for middle and late stage and refractory pediatric malignant solid tumors. The enrollment criteria for children with tumors: after the standard treatment plan (including surgery, radiotherapy, chemotherapy and other comprehensive treatments) is given to different types of diseases, and after the discussion and evaluation of the multidisciplinary collaborative group of children’s tumors of Xinhua Hospital, patients with the primary mass reduced by less than 50%, or the disease progressed or recurred. As of April 2013, 38 cases of extracranial solid tumors and 43 cases of brain tumors were detected. 27 of the 38 children with extracranial solid tumors were male and 11 were female, and the median age of onset was 5 years (1-14 years). Among them, there were 16 cases of neuroblastoma, 5 cases of rhabdomyosarcoma, 3 cases of nasopharyngeal carcinoma, 3 cases of primitive neuroectodermal tumor (PNET), 3 cases of hepatoblastoma, 2 cases of osteosarcoma, 2 cases of infantile fibrosarcoma, 2 cases of yolk sac tumor, 1 case of Ewing’s sarcoma, and 1 case of B-cell lymphoma. Among the 38 extracranial solid tumor specimens, 35 were surgical specimens, 3 of which were secondary surgical specimens and 3 were peripheral blood specimens for individualized tumor molecular target detection. Chain reaction (PCR) amplification and sequencing were used to determine the corresponding drug-related molecular targets. Mesenchymal tissues are developed from mesenchymal mesenchyme, such as adipose, vascular, bone, cartilage, rhabdomyosarcoma, smooth muscle, synovium, and mesothelium, etc. Neuroblastoma originates from ectodermal neural crest cells, and neurogenic tumors are clearly different from mesenchymal-derived tumors.3 Therefore, the above common tumor pathologies are divided into 2 types: 13 cases of mesenchymal origin (rhabdomyosarcoma, PNET, Ewing’s sarcoma, Osteosarcoma, infantile fibrosarcoma) and 25 tumors of non-mesenchymal origin (neuroblastoma, hepatoblastoma, yolk cystic tumor, B-cell lymphoma, nasopharyngeal carcinoma) to compare whether there is any difference in the detection of chemotherapeutic drug targets between common drugs in mesenchymal and non-mesenchymal origin tumors; and to compare neuroblastoma and soft tissue tumors (rhabdomyosarcoma, osteosarcoma, fibrosarcoma, PNET) tumor specimens for vascular endothelial Growth factor receptor-2 (VEGFR-2 ) and intercellular adhesion molecule-1 (ICAM1) molecular target assays in peripheral blood specimens were compared for sensitivity to bevacizumab.