Targeted contrast agent developed for breast cancer
Harvard researchers have developed a contrast agent that selectively targets and highlights malignant micro-calcifications in the breast, while ignoring similar micro-calcifications found in benign breast conditions. Details of the new technique were revealed at the American Chemical Society in Chicago last week. The work was completed in the laboratory of John Frangioni, MD, PhD, associate professor of medicine and radiology at Harvard Medical School.

The non-invasive imaging method uses harmless light instead of x-rays, and has the potential to aid doctors in diagnosing disease within minutes and highlight where biopsies are needed.

“Because this agent is highly selective in targeting the product of malignant tumors, this approach may prove most useful for monitoring women who have dense breast tissue, or those who are at a higher-than-average risk for developing a malignant breast tumor,” Frangioni said.

The new technique would not likely replace mammography, according to Frangioni, but rather to supplement it. Using the two methods together, he said, could catch more cancers than mammography alone.

Nearly half of women under 50 and a third of older women have naturally dense breast tissue, making it harder to distinguish between healthy tissue and questionable masses in mammograms, Frangioni said.

The new agent works by binding to micro-calcifications produced in breast cancers.

“By honing in on hydroxyapatite, we can target these malignant cells with a high degree of specificity, and that has the potential to improve the patient’s outcome,” Frangioni said.

The contrast agents use a combination of bisphosphonate, a type of drug used to strengthen bone, with a near-infrared fluorophore. When used with optical tomography doctors can reconstruct a 3D image of tissues deep inside the breast, highlighting malignancies.

It’s possible the agents could also be used during surgery to pinpoint the location of hydroxyapatite, and therefore the breast cancer cells themselves, Frangioni added.

Future studies will focus on translating the new compound to the clinic for human testing, which according to Frangioni could be a few years away.