Detection of chromosome 12q amplification in sarcomas by chromosome microdissection and interphase fish

We describe the microdissection of a homogeneously staining region (hsr) in the neuroblastoma cell line NGP-127 which contains the SAS gene. Fluorescence in situ hybridization (FISH) of this probe to NGP-127 cells confirms its derivation from the hsr, while FISH to normal chromosomes establishes that the hsr is composed of sequences from two segments of chromosome 12q. The hsr microdissection probe yields fluorescent signals which are sufficiently intense to readily identify amplification of homologous sequences in interphase nuclei.