Under a laser light, tumor cells light up.
What's the News: Getting out every last bit of a tumor can be difficult--when you've got a patient open on the operating table, cancer cells don't look any different from normal ones. But tag tumor cells with a glowing protein and turn the lights off, as scientists did in a recent study, and those things stand out like glo-sticks on the Fourth of July. How the Heck:
Many (though not all) ovarian cancer cells overexpress a receptor for the molecule folate on their surfaces; normal cells don't have nearly as many. The researchers took advantage of this by infusing patients with folate that had a fluorescent tag attached to it for two hours before surgery.
In surgery, the team could shine a laser light on patients' ovaries and watch the fluorescently tagged folate, now clustered all over the surfaces of tumor cells, light up like a torch on a nearby computer screen.
This clear marker, they think, made it easier to remove very last bit of the tumors--in eight of their nine patients, the team noticed small tumors they would have missed otherwise.
What's the Context:
Of all the gynecologic cancers, ovarian is the most deadly. Only 45% of patients survive past the 5-year mark. Like pancreatic cancer, there are no good diagnostics for the early stages and it's often not caught until it reaches such an advanced stage that large tumors are causing serious rearrangement in the body cavity.
Getting all the tumor out is one of the best ways to help hedge a patient's bets--chances are, the doctors won't get another opportunity to operate, and it means subsequent chemotherapy will be better able to flush out and kill any remaining cells.
Helping surgeons tell healthy cells from sick with fluorescent tags is being explored in other areas as well--scientists who tagged healthy nerve cells in mice say the technique could be used to help surgeons avoid causing nerve damage.
The Future Holds: The team's paper doesn't describe the long-term results of their trial--have the patients gone into remission? Do they think that more patients overall will go into remission if the technique is used? Those are questions for larger, longer-term follow-up studies. Reference: M van Dam, et al. Intraoperative tumor-specific fluorescence imaging in ovarian cancer by folate receptor-α targeting: first in-human results. Nature Medicine. published online 18 September 2011; doi:10.1038/nm.2472
Image courtesy of Nature Medicine and van Dam, et al.