Analysis of G banded karyotypes in myeloma cells.

Karyotypes of bone marrow cells from 24 patients with multiple myeloma (MM) and two patients with de novo plasma cell leukaemia (PCL) were analysed by Giemsa banding (G banding). Chromosome aberrations were found in 13 patients with MM and both patients with PCL. Hyperdiploid and hypodiploid lines were present in eight and five of the patients with MM, respectively. Marker chromosomes derived from structural rearrangements were present in all eight cases of MM with hyperdiploid lines, although markers of uncertain origin were rare in those patients with hypodiploid lines. Chromosome 1 participated most often, and chromosomes 5 and 9 often played a part in the structural rearrangements. Chromosomes 3, 5, 7, 9, 11, 15, 19, and 21 were subject to numerical aberrations. In the two patients with PCL one had a hypodiploid line with a 14q + marker derived from a t(11;14) and the other a hyperdiploid line. The breakpoints on the chromosomes participating in the structural rearrangements in myeloma showed a good correlation with known fragile sites and oncogene locations on the corresponding chromosomes.