Molecular cloning of a new gene which is differentially expressed in breast and prostate cancers

Objective: The chromosomal region 19q13 is non-randomly rearranged in many solid tumors. Methods: Using the positional candidate gene approach, we cloned a new gene, tentatively named cancer-associated gene (CAG), which is differentially expressed in breast and prostate cancers. Results: The gene is formed of 3 exons and 2 intervening introns. Its coding region is 1,047 bp in length and is predicted to encode a 348-amino-acid polypeptide. The new gene maps to chromosome 19q13.4 and is located 14 kb telomeric to the kallikrein gene locus (KLK14 gene) and 17 kb centromeric from the Siglec family of genes ( Siglec- 9). The gene is expressed in a wide variety of tissues including the brain, colon,kidney and pancreas. The CAG protein shows a high degree of conservation among species and phylogenetically is most closely related to its mouse ortholog. In silico analysis indicates that this gene is differentially expressed in a variety of tumors including brain, colon, ovarian and prostate cancers. Conclusions: Our preliminary experimental data show that CAG is upregulated in prostate cancer tissues compared to normal prostatic tissues. CAG also appears to be downregulated in breast cancer tissues. The physiological function of the CAG protein is currently unknown. Copyright (C) 2004 S. Karger AG, Basel.