A new BC Cancer Agency study may have discovered a way to use a simple dye as a way  to identify abnormal areas of the mouth that may become cancers. According to a study published in the September 1 issue of Cancer Research, BC Cancer Agency scientists found that lesions absorbing a dye known as toluidine blue were six times more likely to become oral cancers.

Toluidine blue is often used to detect oral cancers, says Dr. Miriam Rosin, director of BC Cancer Agency's Oral Cancer Prevention Program. This study, however, demonstrated that the dye accurately predicts which pre-malignant lesions are likely to become cancer.

The dye was applied to lesions in the mouths of 100 patients during dental visits to determine the value of the stain for imaging precancerous lesions. Researchers found that toluidine blue-stained lesions became squamous cell carcinomas more quickly than lesions that did not stain. By the time the study is completed, four hundred patients will be monitored.

"The disease is usually identified fairly late in progression," Rosin said. "At that stage, it is frequently not amenable to the successful intervention that we'd like. The whole deal of changing survival outcome is that you have to get at the disease earlier.With enough training of those who are doing the screening, the dye should help the clinicians find those patients with lesions that should really be moved forward for assessment."

The researchers also discovered that the dye-staining lesions contained molecular alterations that are linked to high risk of oral cancers—even at early stages, showing that lesions which absorb the dye are not only abnormal at a gross tissue level, but also at a molecular level as well.

"Oral premalignant lesions that stained with toluidine blue consistently contained loss of chromosomal genetic information," Rosin said. In patients with dye stained lesions, Rosin and colleagues found a strong association with loss of genetic information, termed loss of heterozygosity (LOH), on one or more chromosomes. 

This study is the first in a new Oral Cancer Prevention Program, led by Dr. Rosin. 

The findings are among the first steps in designing and implementing an imaging screening program that dentists and oral hygiene professionals can use to make first-line decisions about early stage biopsies and referrals for anti-cancer related care. 

British Columbia is an excellent environment for developing a model to screen and identify high risk lesions among dental patients. Ninety percent of the province's residents see a dentist at least once every two years. Approximately 2,500 dentists in British Columbia form a potential province-wide screening network that will forward high risk patients to special care facilities.

Training and technology should enable the people at the point of screening to determine whether the lesion should be monitored, or if the patient should be referred for further assessment. In some cases, the dentist can decide immediately whether a biopsy should be taken at that point.

The multidisciplinary research team that collaborates with Rosin includes pathologists, oral medicine specialists, dentists, oral surgeons, radiation oncologists, molecular biologists, statisticians and epidemiologists. Her colleagues include Lewei Zhang, the lead author on the publication, Catherine Poh, Robert Priddy, Faculty of Dentistry, University of British Columbia; Michele Williams, Joel Epstein, Scott Durham, Nhu Le, Greg Hislop, John Hay, Wan Lam, BC Cancer Agency; Hisae Nakamura, Denise Laronde, Simon Fraser University; and Ken Berean, UBC Hospital, Vancouver, B.C., Canada.

Funding for this study was provided by the National Institute of Dental and Craniofacial Research.

The BC Cancer Agency, a part of the Provincial Health Services Authority, is committed to reducing the incidence of cancer, reducing the mortality from cancer, and improving the quality of life of those living with cancer. It provides a comprehensive cancer control program for the people of British Columbia by working with community partners to deliver a range of oncology services, including prevention, early detection, diagnosis and treatment, research, education, supportive care, rehabilitation and palliative care. The BC Cancer Research Centre conducts research into the causes and cures for cancer.

For more information, please contact:
Nicole Adams
BC Cancer Agency
Tel: 604.877.6272
Pager: 604.641.5167
Email: nadams@bccancer.bc.ca