c-Myc-Associated Genomic Instability of the Dihydrofolate Reductase Locus in Vivo

c-Myc overexpression is associated with the locus-specific amplification and rearrangement of the dihydrofolate reductase (DHFR) gene. This has been shown in lymphoid and nonlymphoid cell lines. Furthermore, c-Myc-dependent DHFR gene amplification occurs independent of species origins; it has been described in rat, hamster, mouse, and human cell lines. Here, we report on c-Myc-dependent amplification of the DHFR gene in vivo, using an animal model of c-Myc-dependent neoplasia, the mouse plasmacytoma.