!Name=Pollack et al (1999). Nature Genetics 23, 41-46. !ExptSetNo=182 !Description=Gene amplifications and deletions frequently contribute to tumorigenesis. Characterization of these DNA copy-number changes is important for both the basic understanding of cancer and its diagnosis. Comparative genomic hybridization (CGH) was developed to survey DNA copy-number variations across a whole genome. With CGH, differentially labelled test and reference genomic DNAs are co-hybridized to normal metaphase chromosomes, and fluorescence ratios along the length of chromosomes provide a cytogenetic representation of DNA copy-number variation. CGH, however, has a limited ( approximately 20 Mb) mapping resolution, and higher-resolution techniques, such as fluorescence in situ hybridization (FISH), are prohibitively labour-intensive on a genomic scale. Array-based CGH, in which fluorescence ratios at arrayed DNA elements provide a locus-by-locus measure of DNA copy-number variation, represents another means of achieving increased mapping resolution. Published array CGH methods have relied on large genomic clone (for example BAC) array targets and have covered only a small fraction of the human genome. cDNAs representing over 30,000 radiation-hybrid (RH)-mapped human genes provide an alternative and readily available genomic resource for mapping DNA copy-number changes. Although cDNA microarrays have been used extensively to characterize variation in human gene expression, human genomic DNA is a far more complex mixture than the mRNA representation of human cells. Therefore, analysis of DNA copy-number variation using cDNA microarrays would require a sensitivity of detection an order of magnitude greater than has been routinely reported. We describe here a cDNA microarray-based CGH method, and its application to DNA copy-number variation analysis in breast cancer cell lines and tumours... !Name=1X vs 2X (sva136_sf) !Exptid=6084 !Name=2X vs 2X (sva101_sf) !Exptid=6067 !Name=3X vs 2X (sva048_sf) !Exptid=6046 !Name=4X vs 2X (sva047_sf) !Exptid=6045 !Name=5X vs 2X (sva046_sf) !Exptid=6043 !Name=BT474 vs NF (sva026_sf) !Exptid=6040 !Name=MCF7 vs NF (sva126) !Exptid=6081 !Name=UACC-812 vs NF (sva035_sf) !Exptid=6041 !Name=BC-2 vs NF (sva111_sf) !Exptid=6076 !Name=HMEC X BT474 (sva117_sf) !Exptid=7685