Metastatic neuroblastoma in an infant: translocation (1;11), deletion (2) and double minute chromosomes.

An extensive chromosomal analysis was performed in cells of primary tumour and bone marrow metastases from an 8-month-old girl with disseminated neuroblastoma prior to therapy. A modal chromosome number of 46 was found. Consistent abnormalities in the karyotype were seen: in particular, a translocation (1;11), a deletion (2)(p21) and a chromosome 7p+. Furthermore, double minute chromosomes of two distinct sizes were found in 50%-80% of metaphases in the cell populations examined. These extra chromosomal double minutes might be the cytogenetic form of amplified cellular oncogene-DNA.