A prerequisite for the study of biological characteristics in neuroblastoma is the establishment of cell lines from tumors of patients. For our study a neuroblastoma cell line, IGR-N-835, was established from a primary tumor. During in vitro establishment of this line morphological changes were observed. IGR-N-835 exhibited both anchored cells and floating clusters. When cultured on bovine endothelial corneal cellular matrix, all tumor cells anchored to the matrix and proliferated, giving a continuous cell line. IGR-N-835 was studied in vitro and in vivo. Treatment with retinoic acid resulted in cell growth arrest and morphological differentiation. IGR-N-835 was highly tumorigenic in nude mice, exhibited a doubling time of 65 hr and was able to form colonies in methyl-cellulose with a cloning efficiency of 0.46%. Immunocytochemical studies showed reactivity of this line and its primary passages with CE7 monoclonal antibody (MAb). Cytogenetic analyses revealed stable mode and markers resulting from structural changes in chromosomes 10, 11 and 21 with no homogeneously staining regions or double minute chromosomes. Genomic amplification and overexpression of the N-myc oncogene exhibited by the patient's tumor remained unchanged in nude mouse xenografts and the IGR-N-835 cell line. These phenotypic and genotypic traits were unchanged during establishment of this neuroblastoma line. IGR-N-835 could therefore constitute a suitable material for the study of the biology or therapeutics of human neuroblastoma.