Posted on behalf of Zoe Cormier.

Japanese researchers have developed a probe for ovarian cancer that can be sprayed onto tissue during surgery, fluorescing where malignant cells are present — allowing surgeons to identify and remove scattered bits of tumour.

Ovarian cancer has a tendency to spread, leaving small tumours of less than a millimetre in diameter throughout the abdominal cavity, which can be hard for surgeons to spot and remove — being able to find all the malignant cells is crucial for a good survival outcome.

In September, I reported on a similar use of fluorescent labels to identify cancer cells during surgery (see Glowing cells guide cancer surgeons). Researchers at the Technical University of Munich in Germany used a probe for ovarian cancer in human patients, which targeted ovarian tumours by binding to a folate receptor expressed only on the surface of diseased cell.

But that probe was administered through injection — and can take hours to appear.

“Our probe is actuated in minutes or even seconds — that’s very important for the surgeon, who can’t necessarily wait 20 minutes,” says Hisataka Kobayashi of the University of Tokyo, author of the new study published in Science Translational Medicine.



Kobayashi’s team developed a probe that is “activatable”: it glows after being transformed by an enzyme that sits in the cell membrane of ovarian cancer cells. It is activated during passage into the cell, so the probe only starts to glow once inside the diseased tissue.

They first tested this in human ovarian cancer cell lines in vitro, then moved to mouse models. They are now trying to evaluate the probe using fresh tumour specimens from human patients, rather than in vitro cell lines. “We are now on the way to producing a compound that is suitable for a human study,” he says. They are also working towards using this probe with gastric, colon, liver and uterine cancers.

There is a video of the spray in action below…but it’s not for the squeamish!

Video courtesy of Yasuteru Urano.