Tumor Paint' Illuminates Cancer Cells

Author:  Hoi See Tsao

Institution:  Wellesley College
Date:  July 2007

Researchers from the Seattle Children's Hospital Research Institute and Fred Hutchinson Cancer Research Center have discovered that the molecule chemotoxin, which is found in scorpions, binds specifically to tumor cells. By developing the molecule into a type of tumor paint,' surgeons could possibly target cancer cells more accurately during surgeries and decrease the chances of remission.

Using a mouse model, the researchers were able to demonstrate that brain tumors as small as 1 mm in diameter could be "lit up" using chemotoxin, which emits infrared light. Currently, surgeons often have to rely on color, texture and blood supply to determine whether a cell is cancerous. As these features are often subtle, chemotoxin could greatly improve the accuracy of tumor removal, especially in organs such as the brain, where it is imperative that healthy neurons remain undamaged and where approximately 80 percent of malignant cancers grow back at surgical area edges.

The team published their findings in the journal Cancer Research. Researcher Dr. James Olsen said in an interview with the BBC, "By allowing surgeons to see cancer that would be undetectable by other means, we can give our patients better outcomes. My greatest hope is that tumor paint will fundamentally improve cancer therapy."

While experts emphasize the need to determine the mechanism behind why chemotoxin binds specifically to tumor cells and to ensure that it is not toxic to humans, the researchers involved in the study are hopeful that the "chemotoxin paint" could be used for the surgical removal of many types of cancer in patients in as little as 18 months.

Professor John Griffiths, head of molecular imaging at Cancer Research UK's Cambridge Research Institute, said, "The big problem with surgery for brain cancer is that tumors can infiltrate normal brain tissue, making it very hard to tell where the tumor ends and the normal tissue begins. If you could light up the tumor cells by shining an infrared beam on them, it might be very helpful."

Written by Hoi See Tsao