Laura Marcu: Distinguishing normal from malignant tissue
One way to better the odds of survival for patients with brain tumors is to improve the way neurosurgeons determine whether or not they have removed all cancerous cells. If just a few cells are left behind, the cancer will recur in a short time.
Laura Marcu, associate professor of biomedical engineering at UC Davis, has developed a new device and technique for distinguishing — with pinpoint accuracy — normal from malignant brain tissue while the patient is still on the operating table.
“Our method allows neurosurgeons to just shine a light on the tissue to determine whether or not it's cancer,” said Marcu, who did her postgraduate training in spectroscopy, lasers and plasma physics at the University of Bucharest in Romania and earned her Ph.D. in biomedical engineering at the University of Southern California. She joined UC Davis in 2006 from Cedars-Sinai Medical Center in Los Angeles.
The optical "biopsy"
Marcu's novel technology uses laser light to excite molecules within tissues. The molecules respond by fluorescing. Different molecules, depending on their chemical properties, emit light of different colors. Using sensitive optoelectronic equipment, the device detects and analyzes this emitted light using a process known as "fluorescence lifetime" or "time-resolved" measurement. The wavelength of the emitted light is determined and the time it takes for the fluorescing molecules to revert to their preexcited state is measured. The biochemical status of the tissue is what is used to distinguish normal from malignant cells.
The portable set-up Marcu has created in her laboratory includes a fiberoptic probe that delivers an impulse of laser light and collects the re-emitted light and its decay in nanoseconds. Marcu's approach, known as time-resolved fluorescence spectroscopy and imaging, is one of several techniques under investigation at UC Davis Comprehensive Cancer Center for near-instantaneous optical "biopsy."
Preliminary data suggest Marcu's technology will represent a significant advance in brain cancer surgery. Using her first prototype device, neurosurgeons at Cedars-Sinai Medical Center, where Marcu began her research, were able to correctly identify tumor cells left behind after the removal of glioblastomas from 17 patients. Glioblastomas are irregularly shaped brain tumors with poorly defined borders that invade neighboring tissue.
Bringing the new technology to patients
With her Cedars-Sinai collaborators, Marcu is now recruiting glioblastoma patients for a research clinical trial. The 100-patient study will also include patients being treated at UC Davis Comprehensive Cancer Center.
Marcu is also working to apply this technology to cancers other than those of the brain. She has teamed up with Gregory Farwell, a UC Davis associate professor of otolaryngology, who will use the device on patients with head and neck tumors.
Since arriving at UC Davis two years ago, Marcu has been busy setting up her new lab and establishing collaborations like the one with Farwell. She enjoys hiking, fencing and skiing. Fencing, in particular, requires skills similar to those needed to take on cancer research.
“You have to stay focused, predict your ‘enemy’ tactics, maintain balance, and develop strategies for winning,” she said.
Likewise, Marcu finds her personality well suited to the task of applying biomedical engineering principles to the challenges facing modern medicine.
“Research by definition is a dynamic activity,” she said. “The challenge is to bring it to the next level. That is to use the knowledge gained though research to develop new and practical technologies to treat and diagnose human diseases.”
The opportunity to take new discoveries directly to the bedside where they can benefit patients is what drew Marcu to UC Davis.
"This is a wonderful environment for bringing new technology into practice," she said. "UC Davis has the people and the resources to make new advances happen."