Rethinking Healthcare

Glowing cancer cells help surgeons remove tumors from ovaries

Posting in Cancer

Ovarian tumor cells tagged with a fluorescent marker light up, allowing surgeons to remove cancerous tissue that could otherwise cause relapses. In humans!

Ovarian cancer cells in humans, illuminated.

Scientists have found a way to label cancerous tissue with a fluorescent marker, making them incredibly visible so that doctors can track their spread and precisely remove them during surgeries.

In humans! Watch them glow.

It’s not always easy for surgeons to figure out the border between tumors and healthy tissue – which sometimes results in relapse from the regrowth of cancer cells that were left behind. Getting it all the first time helps chemotherapy kill the rest.

For their new surgical imaging technique, a team led by Gooitzen van Dam of University of Groningen in The Netherlands took advantage of a malignant cancer trait: most ovarian cancer cells express lots of receptors for a molecule called folate (better known as vitamin B9 or folic acid). Cancer cells need this to grow and divide.

By attaching a fluorescent label (called fluorescein iso-thiocyanate) to folate, Nature News explains, the researchers created a cancer-cell probe.

  1. They injected this into 10 women undergoing ovarian cancer surgery.
  2. A special camera system, called a multispectral fluorescence camera, lights up the cancer cells and displays their location on a flat-screen monitor next to the patient during surgery.

It’s called fluorescence-guided surgery, and you can watch a video of the first surgery. (Pictured: naked eye vs. fluorescence dye.)

The system enabled surgeons to precisely determine the extent of the tumor’s spread, allowing them to visualize cancer cells in real time during operations.

They found on average 34 tumors, compared with just 7 picked up by traditional observations alone.

"Until now we could only rely on the human eye to find carcinogenic tissue, or non-specific dyes that would color the vascular tissue as well as particular cancer cells,” says study coauthor Vasilis Ntziachristos from the Technical University of Munich. “Now we are going after precise molecular signals and not simply physiology."

Ovarian cancer is notoriously difficult to see, and this technique allowed surgeons to spot a tumor one-tenth of a millimeter big. That’s 30 times smaller than the smallest they could detect using standard techniques, says study coauthor Philip Low at Purdue University in Indiana.

About 80% of uterine, lung and kidney cancers, and 50% of breast and colon cancers also overexpress the folate receptor.

Endocyte holds the license to the folate receptor-targeting technology and is spinning this technology off into a new company called OnTarget. A startup company named SurgOptix BV is working to commercialize the camera system.

The study was published in Nature Medicine this week.

Image: Gooitzen van Dam

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Janet Fang

Contributing Editor

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York. Follow her on Twitter. Disclosure