Mapping the amplification of EIF3S3 in breast and prostate cancer

Gain of chromosome arm 8q is a frequent genetic alteration in breast and pr ostate cancer. Two amplified subregions, 8q21 and 8q23-24, have been identi fied with comparative genomic hybridization (CGH). We have recently demonst rated that the EIF3S3 (eOF3-p40) gene, located at 8q23, is often amplified and overexpressed in both breast and prostate cancer. Here, we used fluores cence in situ hybridization (FISH) to map the amplified region around EIF3S 3 in primary breast cancers and cell lines. The size of the common highly a mplified region was about 2.5 Mb between the markers D8S1668 and WI-7959. N ext, we analyzed the expression of all expressed sequence tags (ESTs) locat ed within and near this region by RNA slot blot hybridization. In addition to EIF3S3, three anonymous ESTs and EXTI were found to be highly expressed in cancer cell lines with the amplification at 8q23-q24. However, the anony mous ESTs were located outside the minimal highly amplified region and EXTI was overexpressed only in one of the cancer cell lines with 8q amplificati on. Since EIF3S3 was the only consistently overexpressed gene located in th e minimal highly amplified region, it is the strongest candidate target gen e for 8q23-q24 amplification. Genes Chromosomes Cancer 28:203-210, 2000. (C ) 2000 Wiley-Liss, Inc.