Molecular cloning and characterization of LOH11CR2A, a new gene within a refined minimal region of LOH at 11q23.

Deletions at chromosome 11q23 are frequent events in a variety of human neoplasms, including breast, lung, and ovarian carcinomas. Two common regions of loss of heterozygosity, shared between lung and breast carcinomas, have been previously identified at 11q23, suggesting that the same tumor susceptibility genes are altered in these two malignancies. One of these regions, refined in lung adenocarcinoma, is included between loci D11S1345 and D11S1328. Here, we describe the refinement of the same region in breast carcinomas and the characterization of a new gene found within this area. The gene, called LOH11CR2A, spans an area of approximately 40 kb and is transcribed at a low level in all the tissues in which it has been analyzed. The predicted amino acid primary sequence revealed no homology with other proteins that could help to elucidate a possible function for the LOH11CR2A protein. Here, we tested the hypothesis that LOH11CR2A could be a tumor suppressor gene. Analysis of human breast, lung, and ovarian carcinomas revealed the presence of several amino acid substitutions in the coding region of this gene. However, a role for these amino acid changes in the tumorigenic process could not established.