Determination of amplicon boundaries at 20q13.2 in tissue samples of human XXXX by high-resolution microarray comparative genomic hybridization.

@entity5 @entity50879 @entity29381 @entity74 @entity356
Comparative genomic hybridization (CGH) of @entity356 frequently shows gains and amplifications of chromosome 20. However, the underlying @entity74 is unknown and conventional CGH results do not allow specification of the target region. In order to investigate this chromosomal aberration with a higher resolution and sensitivity, microarray-based CGH was performed with both scanning and high-resolution arrays of chromosome 20 in a series of 27 @entity356 . Locus-specific fragments of genomic DNA from bacterial artificial chromosome (BAC) clones were spotted as microarrays. A scanning array contained a set of 27 BAC clones covering chromosome 20q. A high-resolution array contained 27 overlapping BAC clones at 20q13.2. This high-resolution array was used to narrow down the amplicon at 20q13.2 in @entity5 showing amplification of this chromosomal region with the scanning array. Positive copy number changes on chromosome 20q were detected in 12 of 27 cases (44%). These changes included gain of the whole arm of chromosome 20q in 8 of 27 (30%) cases, amplification restricted to 20q12.1 in one case, and amplifications restricted to 20q13 in three cases (11%). The three @entity5 showing amplification restricted to 20q13 were analysed further using the high-resolution array. In one @entity5 , the whole contig was amplified at a constant level. One of the other two @entity5 had a clear proximal breakpoint, while the other @entity5 had a clear distal breakpoint within the 20q13.2 region. The proximal and the distal breakpoint were approximately 800 kb apart. In the present study, an amplicon at 20q13.2 has been narrowed down to 800 kb which is likely to harbour one or more putative oncogenes relevant to @entity356 , for which @entity50879 and @entity29381 are good candidates.
