Identification of two novel breast cancer associated genes by the differential display method
© Current Science Ltd 2000
Published: 12 March 2000
Using the Differential Display (DD) technique we identified two novel genes that are over-expressed in human breast cancer cells compared to various other human cancer cells which were screened for differentially expressed genes.
Messenger RNAs were transcribed, followed by PCR amplification and visualisation of the cDNA subpopulation by polyacrylamide gel electrophoresis. Eight human tumor cell lines where used to select differentially expressed genes by DD. Cloning and sequencing of two overexpressed cDNA clones in MCF 7 breast cancer cells identified two novel genes. By FISH analysis one gene was mapped on the X chromosome and therefore designated 'breast cancer associated gene on chromosome X' (BG-X). The second novel gene, designated DAM1 (DNA amplified in mammary carcinoma) was mapped on the chromosome 1p13.3-21 region, which is frequently altered in human breast cancer. Northern blot analysis of BG-X revealed ubiquitous expression in normal human tissue (eg kidney, pancreas, small intestine, stomach, colon, ovary, liver, brain, heart) and in breast cancer cells (7/7), but no expression in several human cancer cells (carcinomas of pancreas (1/9), stomach (0/7) and prostate (0/4)). Using an enhanced green fluorescent protein (EGFP) assay, the EGFP-BG-X-fusion protein was localised in the cell nucleus. Our data present two novel genes with strong expression in human breast cancer cells and down-regulation in several other cancer cell lines.