NONSYSTEMIC AMPLIFICATION OF MYC WITH CDK4 AND MDM2 IN A MALIGNANT MIXED TUMOR OF SALIVARY-GLAND

Karyotypic analysis of a metastatic malignant mixed tumor of the saliv ary gland revealed the presence of double minute chromosomes (dmin), i ndicative of gene amplification. Comparative genomic hybridization ana lysis of DNA extracted from the primary and a renal metastasis indicat ed overt amplification of DNA sequences derived from 8q23-24 and 12q13 -15 regions. Subsequent Southern blot analysis of tumor DNA from the m etastasis with the use of probes previously mapped to those regions in dicated amplification of MYC at 8q23-24 and CDK4 and MDM2 at 12q13-15. Fluorescence in situ hybridization of differentially labeled MYC and MDM2 genes hybridized to tumor metaphase chromosomes revealed an indep endent nonsyntenic amplification of MYC and MDM2 on dmin in this tumor . (C) Elsevier Science Inc., 1998