Mammograms are useful tools for diagnosing breast cancer, but they don't always get it right. It's not always easy to tell how dangerous a particular tumor is, meaning harmful but treatable cancers can be missed, while other patients with benign tumors undergo unnecessary invasive procedures. Now, scientists at the University of Michigan have developed a new diagnostic tool that's much easier to swallow – a pill that makes tumors glow under infrared light.

To take imaging down to the molecular level, the researchers designed an oral pill that can deliver a fluorescent dye to tumors in breast tissue. Once there, doctors can perform an infrared scan on the breast, and the dye will cause cancerous cells to reflect the light.

It may sound simple, but the researchers say it was a challenge to find the right molecules for the job. They needed to be small and lipophilic (greasy) enough to be absorbed into the bloodstream, but large and water-soluble enough to show up in a scan. The dream molecule turned up in a failed cancer-fighting drug, which was found to successfully bind to tumors but then not do any actual cancer-fighting.

But that was enough for a diagnostic tool. The U-M team tuned the molecule to only bind to proteins on the surface of malignant cancer cells, and attached a fluorescent molecule to the targeting one. That way, patients can take a pill, then doctors perform an infrared scan on their breasts and check if anything's glowing. Tests on mice showed that the technique works.

The researchers say that this new method is less invasive than a mammogram, and more precise. That said, mammography will still have its place, but doctors will be able to make more efficient use of the technique. Being able to better distinguish between benign and malignant cancers will benefit all patients; those with tumors that don't pose a threat to their health can be spared the discomfort and cost of chemotherapy or surgery, while patients who do need those procedures will enjoy shorter waiting lists.

"We overspend US$4 billion per year on the diagnosis and treatment of cancers that women would never die from," says Greg Thurber, lead researcher on the study. "If we go to molecular imaging, we can see which tumors need to be treated."

As an added bonus, infrared scans are safe, without the risks of X-rays used in a mammogram.

The research was published in the journal Molecular Pharmaceutics, and the team describes the work in the video below.

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