“Screening Pill” Could Offer Noninvasive Breast Cancer Screening Method

Researchers have developed a “disease screening pill” that could allow for a noninvasive and safe method for detecting breast cancer using only near-infrared light. The pill has been tested only in mice so far, but shows promise for future use.

“Molecular imaging has significant potential for disease screening applications by providing both spatial and molecular information to the physician, but so far, a feasible approach has not been developed,” wrote study authors led by Greg M. Thurber, PhD, of the University of Michigan in Ann Arbor. “Oral delivery provides several advantages over other avenues of administration that can be grouped into three main categories: safety, cost, and compliance.”

The researchers combined a ligand-targeting integrin, which is expressed significantly in breast cancer cells, with dye molecules attached to sulfate groups. They tested this in a xenograft mouse model of breast cancer, and showed that the tumors in these mice had “significant uptake” of the molecule within 6 hours after administration.

An analysis of image intensity shows that the amount of imaging agent stayed relatively constant over a period of 48 hours. The agent allowed for clear imaging of breast tumors using only near-infrared light, rather than an ionizing radiation source.

“Results from this study demonstrated that molecules can overcome the significant physical and kinetic barriers for sufficient oral delivery and targeting of molecular imaging agents in living subjects,” the authors wrote. They published the study in Molecular Pharmaceutics.

They noted that there would need to be a period of days between the point at which a patient swallows this pill and the imaging is done, in order to allow for the agent to be fully absorbed and cleared from any background tissue. They argue, though, that this is still preferable to other routes of delivery, since, for example, intravenous delivery of low-molecular-weight agents still requires a waiting period of hours and carries risks not associated with oral administration, such as the potential for anaphylaxis.

“To our knowledge, this is the first demonstration of a disease screening approach using oral administration of a molecular imaging agent, and these mechanisms should be applicable to additional agents and disease targets for developing a series of molecular imaging agents for noninvasive screening,” the authors concluded.