Stromal cells and human malignant neuroblasts derived from bone marrow metastasis may share common karyotypic abnormalities: The case of the IGR-N-91 cell line

Background. Stage IV neuroblastoma is characterized by tumor invasion and metastatic dissemination. Cell lines derived from such neuroblastomas have a high in vitro proliferation capacity. Procedure. We established three neuroblastoma cell lines derived from involved bone marrow of three patients with stage IV neuroblastoma and performed a cytogenetic study. Results. Various culture conditions allowed us to distinguish two cell subpopulations: Malignant neuroblasts (Nb-type) and substrate-adherent stromal cells (Str-type). Karyotypic analyses revealed two specific chromosomal abnormalities in diploid malignant IGR-N-331 neuroblasts, der(1)t(1;7)(p22;q11) and der(5)t(5;17)(q35;q21), one unbalanced translocation der(1)t(1;17)(p35;q21)×2 in hyperdipioid malignant IGR-N-337 neuroblasts, and a normal karyotype in both corresponding stromal subpopulations. In contrast, in the IGR-N-91 model, both cell types shared two unbalanced translocations, t(1;4)(q12;p15) and t(2;10)(p14;q11), suggesting that stromal cells and malignant neuroblasts originate from a common stem cell. Conclusions. Based on our findings, we postulate that genetically modified stromal cells may influence the metastatic potential of malignant neuroblasts.