[Chromosomal studies in metastatic neuroblastoma]

Chromosomes were prepared directly from primary tumor and bone marrow aspirates of an 8 months old infant and a 2 years old boy with metastatic neuroblastoma. A total of 765 tumor metaphases were counted after Giemsa-banding and partially karyotyped. "Double minute" chromosomes were found in the metaphases of both primary tumor and metastases of the infant, but only in the primary tumor of the older child. In both patients, structural imbalances (in addition to other translocations) were seen in the short arm of chromosome no. 1. The modal chromosome number was 46 in the infant's primary tumor and bone marrow metastases, but 84 in the primary tumor and 46 and over 100 in the bone marrow metastasis of the older child. Clonal evolution of metastasizing neuroblastoma cells is discussed.