Chromosomes 1 and 5 harbor plasmacytoma progressor genes in mice

Mouse spectral karyotyping (SKY) was employed to analyze 29 primary BALB/c plasmacytomas (PCTs) for the presence of chromosomal aberrations that took place subsequent to the Myc-activating T(12F1;15D2) or T(6C1;15D2) transloc ations, the initiating oncogenic mutations in plasmacytomagenesis. Recurren t amplifications of chromosome (Chr) 1 (48% prevalence) and promiscuous non -reciprocal translocations of Chr 5 (52% prevalence) suggested the existenc e of important PCT progressor genes on bands I B/C and 5F. The additional o ccurrence of sporadic aberrations (93% prevalence) most likely reflected th e general instability of the PCT genome. This instability, however, was not consistent, as two PCTs lacked secondary cytogenetic changes detectable by SKY. Our findings led us to conclude that BALB/c PCTs show a remarkably si milar degree of cytogenetic heterogeneity to human multiple myeloma, despit e being genetically defined (inbred mouse strain) and uniformly initiated ( deregulation of Myc). Genes Chromosomes Cancer 29:70-74, 2000. Published 20 00 Wiley-Liss, Inc.dagger.