RD3 and metastatic neoplasm: Despite the inter-tumor and inter-animal variations in the loss of RD3 from the animals bearing spontaneous as well as reproduced high-risk aggressive neuroblastoma, comparison between the panel of primary xenografts to the panel of aggressive metastatic tumors demonstrated (i) consistent strong RD3 positivity in all non-metastatic primary xenografts and (ii) consistent and complete loss of RD3 in aggressive tumors (Supplementary Figure S4C).