A protein that fluoresces and sticks to viable cancer cells, making them easy for physicians to detect, has proved its efficiency when tested in mice, researchers at the U.S. National Cancer Institute said in a study which appeared online on Dec. 7 in the journal Nature Medicine.

The synthetic substance, a combination of the breast cancer drug Herceptin and a fluorescent compound called BODIPY, binds to the HER2 protein certain breast cancer cells contain. Menainv, as researchers named it, glows when it is inside living cells so it may offer doctors a way to spot the spread of the disease Experts agree that the compound may be useful as a biomarker for metastatic breast cancer, the most advanced stage of breast cancer. 

Researchers reached this conclusion after monitoring the spread of breast and ovarian cancer cells in living mice. Using an endoscope, they were able to see breast tumors in the small animals, and tumor cells after they spread away from the initial tumor spot. With more research and extensive testing in human beings, these substances “may also be adapted for use in endoscopy procedures and for use as a surgical aid to improve removal of tumors," lead researcher Dr. Hisataka Kobayashi of the Molecular Imaging Program of NCI's Center for Cancer Research said in a press statement.

Furthermore, researchers also found that tumor cells harboring Menainv are less prone to be responsive to newer breast cancer treatments that inhibit epidermal growth factor receptors (EGFR), which are known to expand breast cancer cells’ invasive potential. Drugs inhibiting EGF may not be effective regarding tumor cells which express Manainv, specialists said.