With a New York University Cancer Institute colleague, the researchers reported that the mixture of free-floating blood proteins created by the enzyme carboxypeptidase N accurately predicted the presence of early-stage breast cancer tissue in mice and in a small population of human patients.
"In this paper we link the catalytic activity of carboxypeptidase N to tumor progression in clinical samples from breast cancer patients and a breast cancer animal model. Our results indicate that circulating peptides generated by CPN can serve as clear signatures of early disease onset and progression," biomedical engineer Tony Hu, Ph.D., who led the project, said.
The technology is not yet available to the public, and may not be for years. More extensive clinical tests are needed, and those tests are expected to begin in early 2014.
There are currently no inexpensive laboratory tests for the early detection of breast cancer, providing the impetus for researchers around the world to invent them.
"What we are trying to create is a non-invasive test that profiles what's going on at a tissue site without having to do a biopsy or costly imaging," Hu said. "We think this could be better for patients and-if we are successful-a lot cheaper than the technology that exists."
CPN is an enzyme that modifies proteins after the proteins are first created. Past studies have only shown the enzyme is more active in lung cancer patients.
The technology being developed by Hu's group combines nanotechnology and advanced mass spectrometry to separate and detect extremely low levels of small proteins (peptides) created by CPN. These peptides are believed to originate in or near cancerous cells, eventually making their way into the bloodstream.
The study is published in Clinical Chemistry.