May 1 (UPI) -- A pill that makes tumors light up when exposed to infrared light could more effectively help diagnose breast cancer, according to a study with mice.
Researchers at the University of Michigan are developing a method to catch cancers not detected by mammograms, and at a lower price than imaging methods such as MRI. The research was published recently in the journal Molecular Pharmaceuticals.
With one in three women undergoing unnecessary procedures -- for benign tumors instead of malignant ones -- the researchers have been looking toward developing an alternate system for diagnosis.
"We are very optimistic given the ability of our technology to detect specific molecular events in tumors," Greg Thurber, an assistant professor of chemical engineering and biomedical engineering at Michigan, told UPI. "We know that cancer is ultimately a disease driven by molecular changes within cells, so measuring these changes -- rather than differences in anatomy -- provides more specific information to the physician."
He noted this approach could be particularly useful for certain situations.
"Patients with dense breast tissue are not only at greater risk of developing breast cancer, but the denser tissue makes tumors more difficult to identify on a mammogram," Thurber said. "Because our approach doesn't rely on tissue density differences, it should be able to spot these higher risk lesions with greater accuracy."
Infrared light penetrates the body more easily than visible light. Using a dye, delivered orally rather than injected into a vein, the system allows for a view of all depths of the breast -- without an X-ray disrupting DNA and possibly seeding a new tumor.
Just a few patients in 10,000 can have severe reactions to intravenous dyes, as opposed to the potential dangers of radiation, making the new system much safer, researchers said.
In tests with mice, the dye responded to the light, tagging a molecule commonly found on tumor cells -- fluorophores -- in the blood vessels that feed tumors and inflamed tissue, causing the tumors light up.
"We have demonstrated that this agent works well in a preclinical animal model of breast cancer," Thurber said. "The probe we developed cannot be used to detect all cancers, so we are developing a second targeting agent that can be imaged simultaneously to cover even more types of breast cancer."
The researchers were challenged to find a molecule that could get from the digestive system to a tumor -- it must be small and greasy to be absorbed into the bloodstream, but imaging agents also must be larger and water-soluble.
The pill used in testing is actually based on a failed cancer treatment that was being developed by Merck. While it was ineffective against cancer in a phase II clinical trial, its ability to get to tumors and attach to a molecule that fluoresces when hit with infrared light made it a winner for Thurber and his team.
"Once the probes are developed, they will need to undergo safety and toxicity studies followed by clinical trials for imaging," Thurber said of the pill. He thinks it could hit the market within five years.
He said the hope is for patients can avoid additional tests and/or treatment as well as physical, psychological and financial hardships.
"We overspend $4 billion per year on the diagnosis and treatment of cancers that women would never die from," Thurber said. "If we go to molecular imaging, we can see which tumors need to be treated."