Localization of amplified MYC gene sequences to double minute chromosomes in acute myelogenous leukemia.

Cytogenetic and molecular studies were performed on two dmin-bearing acute myelogenous leukemia (FAB-M2) samples. Both cases were characterized by complex karyotypes containing interstitial deletions of the long arm of chromosome 8 altering band 8q24.1, aberrations affecting the short arm of chromosome 17, and multiple double minute chromosomes (dmin). Using a 1.4 kb cDNA probe coding for the third exon of the MYC oncogene, DNA slot blots indicated MYC gene sequences were amplified in both samples. Fluorescence in situ hybridization using a 9.0 kb genomic probe for MYC was performed in one case and localized the amplified MYC gene sequences to the dmin. Neither patient achieved a complete remission using traditional induction chemotherapy. The complex karyology with amplification of MYC gene sequences appears to represent a poor prognostic subgroup of acute myelogenous leukemia.