Researchers have designed a light-based therapy that allows the selective destruction of tumor cells in mice without harming surrounding normal tissue. This method of cancer therapy could theoretically work against tumors in humans, such as those of the breast, lung, prostate, as well as cancer cells in the blood such as leukemias, say scientists from the National Cancer Institute (NCI), part of NIH. The study appeared online Nov. 06, 2011, in Nature Medicine.
Current photodynamic therapy is not specific for cancer cells, resulting in damage to surrounding normal tissue. Therefore, the researchers in this study set out to develop a light therapy that could more accurately target cancer cells while sparing a greater number of normal cells.
This new type of treatment, called photoimmunotherapy, or PIT, uses light to rapidly and selectively kill cancer cells. To create their PIT, the scientists coupled a monoclonal antibody or MAb, which recognizes specific proteins on the surface of cancer cells, with a photosensitizer — a molecule that, when exposed to light of the appropriate wavelength (near-infrared), rapidly damages cells. The hope was that the combined photosensitizer/MAb would, by delivering the photosensitizer to cancer cells targeted by the MAb, selectively kill those cells after exposure to near-infrared light.
After evaluating a large number of photosensitizers, the scientists found that a……