title: Identification of novel amplification gene targets in mouse and human breast cancer at a syntenic cluster mapping to mouse ch8A1 and human ch13q34.
abstract: Serial analysis of gene expression from aggressive mammary tumors derived from transplantable p53 null mouse mammary outgrowth lines revealed significant up-regulation of Tfdp1 (transcription factor Dp1), Lamp1 (lysosomal membrane glycoprotein 1) and Gas6 (growth arrest specific 6) transcripts. All of these genes belong to the same linkage cluster, mapping to mouse chromosome band 8A1. BAC-array comparative genomic hybridization and fluorescence in situ hybridization analyses revealed genomic amplification at mouse region ch8A1.1. The minimal region of amplification contained genes Cul4a, Lamp1, Tfdp1, and Gas6, highly overexpressed in the p53 null mammary outgrowth lines at preneoplastic stages, and in all its derived tumors. The same amplification was also observed in spontaneous p53 null mammary tumors. Interestingly, this region is homologous to human chromosome 13q34, and some of the same genes were previously observed amplified in human carcinomas. Thus, we further investigated the occurrence and frequency of gene amplification affecting genes mapping to ch13q34 in human breast cancer. TFDP1 showed the highest frequency of amplification affecting 31% of 74 breast carcinomas analyzed. Statistically significant positive correlation was observed for the amplification of CUL4A, LAMP1, TFDP1, and GAS6 genes (P < 0.001). Meta-analysis of publicly available gene expression data sets showed a strong association between the high expression of TFDP1 and decreased overall survival (P = 0.00004), relapse-free survival (P = 0.0119), and metastasis-free interval (P = 0.0064). In conclusion, our findings suggest that CUL4A, LAMP1, TFDP1, and GAS6 are targets for overexpression and amplification in breast cancers. Therefore, overexpression of these genes and, in particular, TFDP1 might be of relevance in the development and/or progression in a significant subset of human breast carcinomas.
authors.affiliation: Department of Carcinogenesis, The University of Texas M. D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957, USA.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Abba
authors.forename: Victoria T
authors.initials: VT
authors.lastname: Fabris
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Hu
authors.forename: Frances S
authors.initials: FS
authors.lastname: Kittrell
authors.forename: Wei-Wen
authors.initials: WW
authors.lastname: Cai
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: Donehower
authors.forename: Aysegul
authors.initials: A
authors.lastname: Sahin
authors.forename: Daniel
authors.initials: D
authors.lastname: Medina
authors.forename: C Marcelo
authors.initials: CM
authors.lastname: Aldaz
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000235:genetics*; D002874:Chromosome Mapping; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics; D005784:Gene Amplification; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008325:Mammary Neoplasms, Experimental / Q000235:genetics*; D051379:Mice; D005810:Multigene Family; D009693:Nucleic Acid Hybridization; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D004273:DNA, Neoplasm