New dyes 'lighting up' brain cancer cells show promise for 'fluorescence-guided' tumor surgery

A team of scientists has identified two new fluorescent tumor-targeting agents that seek and light up brain cancer cells, suggesting they may help neurosurgeons to more accurately localize and completely resect brain tumors.

Researchers at University of Wisconsin School of Medicine and Public Health evaluated two "tumor-selective" fluorescent agents, called CLR1501 and CLR1502, for their ability to differentiate brain tumors from normal brain tissue in mice.

This study demonstrates the promising potential of CLR1501 and CLR 1502 analogs for use in fluorescence-guided tumor surgery, the researchers conclude.

The new agents were molecularly altered to carry fluorescent dyes that glow under lights with specific wavelengths, either in the green (CLR1501) or near-infrared (CLR1502) range. Viewed under appropriate conditions, the dyes make tumor cells "light up" so that they can be readily distinguished from neighboring normal brain tissue.

In preliminary studies, near-infrared imaging with CLR1502 successfully localized brain tumors through the intact skin and skull of living mice and in addition to fluorescent-guided neurosurgery, APC analogs might play useful roles in diagnosing brain cancers and in targeting chemotherapy drugs directly to cancer cells.

Researcher John S. Kuo and coauthors wrote that upcoming clinical trials in human tumors are planned for these promising tumor-selective fluorescence agents.

The researchers acknowledge the "inherent limitations" of their experiments, limited to implanted tumors in animals. Further research will be needed to assess issues related to dye administration, visualization, and timing, as well as the optimal technologies for practical use during surgery.

The study is published in Neurosurgery, official journal of the Congress of Neurological Surgeons.