Breast Cancer ‘Screening Pill’ Could Be on the Horizon, Mice Study Shows

Breast Cancer ‘Screening Pill’ Could Be on the Horizon, Mice Study Shows

Researchers have developed a pill that marks tumors and lights them up when exposed to infrared light, which could potentially replace mammography in the future, a study in mice has shown.

The study, “Oral Administration and Detection of a Near-Infrared Molecular Imaging Agent in an Orthotopic Mouse Model for Breast Cancer Screening,” was published in the journal Molecular Pharmaceutics.

About 39 million women undergo mammograms each year in the United States. Although mammography unquestionably saves lives, increasing evidence has pointed to an overdiagnosing of breast cancer through mammography, a procedure that exposes the body to X-radiation.

A recent study analyzing data in Denmark showed that about a third of breast cancer patients treated with surgery or chemotherapy have tumors that are benign or so slow-growing that they would not have become life-threatening.

“We overspend $4 billion per year on the diagnosis and treatment of cancers that women would never die from,” Greg Thurber, the study’s senior author, said in a press release.

In addition to the fact that mammography cannot distinguish between aggressive tumors and those that pose no mortality risk, it also has some limitations in detecting cancer in dense breast tissue, and it can miss some treatable breast cancers.

This evidence points to the need for a better strategy to detect and treat malignant breast cancer.

Molecular imaging has great potential in disease screening, as it provides precise spatial information on disease-associated biomarkers, which could indicate tumors that are malignant and need to be treated. So far, however, an effective approach has not been developed.

The development of an orally delivered molecular imaging agent could be a better option, as oral administration is the safest and cheapest method, and patients tend to prefer it.

However, designing such a pill is difficult, as the properties needed for the molecule to be absorbed into the bloodstream are the opposite of the properties needed for an efficient imaging agent.

Researchers at the University of Michigan have now developed a molecule with the perfect balance between those properties, allowing it to be absorbed by the body and to reach tumors while maintaining its efficacy as an imaging agent.

The research team used a molecule called cilengitide, which was tested by Merck in Phase 2 clinical trials as a cancer therapy but was found to be ineffective.

“It’s actually based on a failed drug,” Thurber said. “It binds to the target, but it doesn’t do anything, which makes it perfect for imaging.”

The targeting molecule binds to aVb3 integrin, a cell surface protein highly present in tumor cells, newly formed blood vessels that feed tumors, and inflamed tissue. The researchers attached a molecule that lights up when exposed to near-infrared light, a less expensive and safer radiation that can penetrate deeper into tissue.

When they gave the final molecular imaging agent to mice with breast cancer, the tumors lit up, showing that this approach has the potential to allow physicians to distinguish malignant cancer from a benign tumor by using safer radiation.

“Together, this enables development of a ‘disease screening pill’ capable of oral absorption and systemic availability, target binding, background clearance, and imaging at clinically relevant depths for breast cancer screening,” the researchers wrote.

The team also noted that this approach should be used in other disease targets to develop “a series of molecular imaging agents for noninvasive screening.”

A video in which researchers explain the development of this new “disease-screening pill” is available here.