Different tumorigenicity and distinct metastasis and gene signature between orthotopic and subcutaneous neuroblastoma xenografted mice.

Patient-derived (PDX) and cell-derived (CDX) xenograft models are widely used in preclinical studies of human neuroblastoma. In this study, we constructed orthotopic and subcutaneous neuroblastoma CDX models by injecting human neuroblastoma cells into the adrenal gland and the flanks of immunodeficient mice, respectively. The tumorigenesis, metastasis and response to chemotherapy for the two models were also compared. Our results indicated that orthotopic tumor mice showed significantly faster tumor growth than that of subcutaneous mice. Importantly, the expression of and was dramatically increased in the tumors of orthotopic CDX mice. Furthermore, orthotopic CDX mice developed multiple organ metastasis resembling that of neuroblastoma patients, while metastasis occurred predominantly in lung in subcutaneous CDX mice. Moreover, the two CDX models showed comparable response to cyclophosphamide treatment. Our results suggest that orthotopic CDX mice are superior to subcutaneous CDX mice as a preclinical model to study human neuroblastoma.