On Jul. 15, 2007, Dr. Jim Olson and colleagues from Fred Hutchinson Cancer Research Center and Seattle Children’s developed a “tumor paint” that illuminates cancerous cells so surgeons can see more precisely where a tumor begins and ends.

Chlorotoxin:Cy5.5 is a fluorescent molecular beacon that emits photons in the near infrared spectrum. This illumination gives surgeons a better chance of removing cancerous cells during surgery without injuring surrounding healthy tissue. This is particularly significant in the brain, where approximately 80% of malignant cancers recur at the edges of the surgical site.

Current technology, such as magnetic resonance imaging (MRI), can distinguish tumors from healthy tissue only if more than 1 million cancer cells are present. But Cy5.5 can identify tumors with fewer than 2000 cancer cells, making it 500 times more sensitive than MRI under operating conditions. The study was published in Cancer Research.