To determine which genes may be activated or inactivated during breast cancer development, we employed two cloning strategies (subtractive hybridization and di erential display) using RNA samples from a human breast tumor and its matching normal breast cell line. Of 950 clones isolated, 102 cDNA inserts were analysed by DNA sequencing and database searching. We found 30 clones that were obviously unidenti®ed, with no signi®cant homology to any listed human gene. We focused upon one of the novel genes, Di12, that is di erentially expressed as a 1.35 kb RNA in breast cancer tissues and cell-lines, and in several normal tissues. A full length cDNA of this gene was cloned, and its DNA sequence revealed an open reading frame of 339 amino acids. Antibodies to the ten N-terminal amino acids were developed to investigate the expression of Di12 in breast cancer cell-lines and tumors. The Di12 protein was found in tissue sections of in®ltrating ductal carcinomas (IDCs), but not in benign or normal breast specimens. RT ± PCR analysis con®rmed expression of Di12 in 80% of in®ltrating ductal carcinomas (IDCs). As IDC constitutes *70% of breast cancers seen clinically, the level of Di12 expression may be predictive of disease progression.

Background: Roles for AGS3/Gpsm1 in the immune system are not defined. Results: Loss of AGS3 expression results in defective leukocyte chemotaxis, calcium mobilization, and ERK1/2 and Akt activation. Conclusion: AGS3 is required for efficient chemokine receptor signal integration. Significance: These studies extend the functional repertoire for AGS3 in the immune system, providing unexpected regulatory mechanisms for immune function.

We have shown before that the N8 mRNA is expressed at higher levels in lung tumor and lung tumor-derived cell lines than normal lung cells. In this paper, we have characterized the N8 protein, and studied its properties. The N8 gene encodes a major 24 kDa protein and its expression correlates well with the N8 mRNA expression pattern observed in dierent cell lines. N8 protein is capable of forming a homodimer or multimeter in vitro. It is a phosphorylated cytoplasmic protein and phosphorylation occurs mainly at serine residues. N8 protein is expressed at higher levels in epithelial cells than in mesenchymal cells. N8 protein expression is induced in a ®broblast cell line expressing adenoviral E1a protein, which acquired epithelial-like characteristics. Furthermore, ectopic expression of N8 protein in NIH3T3 cells converts them into a spheroid form. These spheroids also have some of the characteristic features of epithelial cells. Taken together, these results suggest that the N8 protein may be associated with the development or maintenance of epithelial cell phenotype.

Five monoclonal antibodies were produced from mice immunized with recombinant full length human ERGB protein. Among these monoclonal antibodies, four clones did not cross react with other ets family proteins and thus are specific for the ERGB protein; however, one clone did react with the ERG protein, which has high amino acid identity with the ERGB protein. The epitope location of these antibodies was studied using bacterially expressed fragments of the human, ERGB protein. These monoclonal antibodies recognized 51 kDa (p51) and 48 kDa (p48), two ERGB gene-encoded proteins, from human, mouse, and rat cell lines. These results suggest that the monoclonal antibodies can be used in human, mouse, or rat cell lines and will be useful for the biochemical and functional analysis of the ERGB protein.