In a breakthrough study appearing in the journal Nature Methods, researchers at Albert Einstein College of Medicine of Yeshiva University describe for the first time a method of viewing individual breast cancer cells for several days at a time. The study, by scientists in Einstein's Gruss Lipper Biophotonics Center, provides detail on how cancer cells invade surrounding tissue and reach blood vessels. These movements are the first steps of the potentially deadly stage of cancer known as metastasis.

Using intravital imaging, the researchers developed a "photoswitch" to mark cancer cells of their choosing within a tumor and observe how these tumor cells in mice move in their surrounding tissue. The technique allowed researchers to see individually labeled tumor cells move in real time and in living mice.

"One focus of our laboratories has been developing methods to see what cancer cells are doing when followed over time in the most realistic setting," said Jeffrey Segall, Ph.D., professor of anatomy and structural biology.

"Mapping the fate of tumor cells in different regions of a tumor was not possible before the development of the photoswitching technology," explained John Condeelis, Ph.D., co-chair and professor of anatomy and structural biology and co-director of the Gruss Lipper Biophotonics Center.