Among numerous DNA copy number changes, losses of chromosome 13 are highlyrecurrent plasmacytoma

Chromosomal imbalances were studied by comparative genomic hybridization (C GH)on 27 specimens from 24 patients with plasmacytoma. AII the specimens ex hibited DNA copy number changes (mean, 7.7 aberrations/tumor; range, 2-15). The most recurrent change involved losses at 13q, found in 19 out of 24 pa tients. Other frequent losses were at Ip (42%), 14q (33%), X (33%), 8p (25% ), and 6q (25%). Gains were frequent at 19p (58%), 9q (58%), Iq (58%), 7p ( 42%), 11q (38%), 15 (33%), 6p (25%), 8q (25%), and 5p (21%). High-level cop y number increases were found at Iq, 5, 7, 8q, 9q, I Iq, 15, and 19. The fi ndings of highly recurrent chromosomal imbalances in plasmacytomas confirm the analytical power of CGH to detect chromosomal abnormalities in malignan cies characterized by low mitotic activity. Our most striking finding, the losses in chromosome 13, provides a basis to investigate the role of the 13 q loss in the tumorigenesis and progression of plasmacytoma and to evaluate the prognostic significance of this loss. (C) 1999 Wiley-Liss. Inc.