The finding, published in the Aug. 2, 2005, issue of the Proceedings of the National Academy of Sciences and available on-line July 25, shows that the gene, normally made in small amounts in normal breast tissue, somehow becomes over-expressed in breast cancer cells. Researchers hope to use the cancer-specific protein to train the immune system to specifically attack breast cancer cells.
"There is a tremendous need for new molecular targets to treat breast cancer," Radvanyi says. "There are very few bona fide targets that are exquisitely specific for breast cancer. We believe this is one of them."
Radvanyi and his collaborators at Sanofi Pasteur, Toronto, Canada, zeroed in on the gene, called TRPS-1, after an exhaustive search for targets that are found at higher levels in breast cancer than in normal tissue. The researchers compared the gene levels of more than 50,000 known genes in 54 breast cancer specimens and 289 normal samples representing 75 tissues or organs. The breast cancer specimens included 10 examples of early breast cancer or ductal carcinoma in situ (DCIS), 38 locally invasive breast cancers and six representing metastatic disease. They narrowed down their search by eliminating genes commonly found in normal tissue and those predicted to encode proteins that are excreted from the cell.
"We were interested in identifying proteins that could be potential tumor antigens activating cytotoxic T-cells or tumor killer cells," Radvanyi says. "We wanted proteins that would make good targets for a cancer vaccine."
Finally, they zeroed in on TRPS-1, a gene they found at high levels in all forms of breast cancer,
Contact: Nancy Jensen
University of Texas M. D. Anderson Cancer Center