Right now, separating cancer cells from healthy cells is a hit and miss proposition during surgery.
Thanks to a “tumor paint” developed from a scorpion-derived peptide called chlorotoxin (CTX), however, that may soon be a thing of the past. In a study involving mice, Seattle researchers discovered the paint binds to a molecular beacon in cancer cells known as Cy5.5, lighting up the cells for as long as 14 days. That allows surgeons to zero in on far smaller numbers of cancer cells during surgery than has been previously possible.
For example, in brain tumors, surgeons typically can see cancerous tissue only if it contains at least 1 million cancer cells. Using the paint, they can see cancerous tissue with as few as 2,000 cells. The effect is even stronger for other cancers: in a model of prostate cancer, for instance, the paint detected as few as 200 cancer cells in a lymph channel.
The ability to see smaller and smaller groups of cancer cells will allow surgeons to more completely remove tumors, and will also help ensure they leave healthy tissue intact. This is especially vital in brain cancers because most recurrences of the disease take place along the edges of the surgery, where too many cancer cells are left behind.
“For many types of cancer, the precision of surgical resection directly influences patient prognosis,” write the authors. “The technique described here combines an intuitive visual guide for the surgeon with the potential for significant improvement in accuracy and safety by virtue of its molecular precision.”
The scientists are now seeking Food and Drug Administration approval to begin studying the paint in human patients.
SOURCE: Cancer Research, 2007;67:6882-6888
