Currently, diagnosing oral cancer relies on studying the histopathology of tissues through biopsy. X-ray technologies, like computed tomography, and other imaging techniques such as magnetic resonance imaging are sometimes used to detect the location and extent of the primary tumor. These techniques can help determine the stage of the tumor based on its size and whether it has spread. But cancer that can be evaluated by these imaging technologies has already taken root. Now, scientists are looking for ways to find cancer before it becomes clinically evident. To this end, many investigators are searching for markers at the molecular level that could warn of impending cancer.
In one such search for biomarkers, scientists at the University of Texas M.D. Anderson Cancer Center, an NIDCR Oral Cancer Research Center, are looking for alterations in short sequences of DNA called "microsatellites" on p53 and five other genes that might signal oral cancer. By examining cell samples from archived tissue of normal and dysplastic epithelium and invasive lesions, they plan to determine the most consistent biomarkers for each stage of oral cancer. In another phase of the study, the researchers will use tissue from recently diagnosed oral cancer patients to correlate genetic biomarkers with disease stage, tissue changes, tumor aggressiveness, and key epidemiological factors over several years.
One molecule already suspected as a predictor of head and neck cancers is telomerase. This enzyme helps a cell to reproduce chromosomal ends and circumvent the mechanism that counts and limits the total number of times the cell can reproduce. When cells become immortal they appear to bypass this safeguard and are able to replicate without limit. Telomerase is absent from most healthy cells, but present in almost all tumor cells. Scientists at Johns Hopkins University in Baltimore have recently found evidence of telomerase activity in oral rinses collected from head and neck cancer patients. Further research is necessary to discover whether telomerase is a marker consistently associated with head and neck squamous carcinoma. If so, telomerase activity may one day be used to detect the presence of cancer cells in the oral cavity and upper aerodigestive tract.
Until reliable biomolecular markers are identified, clinicians must rely on visual examination of oral tissues to detect precancerous lesions. Research by NIDCR, however, has indicated that less than 15 percent of American adults report they have ever had the head and neck examination that could reveal early signs of cancer. In an effort to improve this situation, NIDCR is focusing on encouraging dentists and other health care practitioners to perform this simple, potentially lifesaving, screening examination.
NIDCR's National Oral Health Information Clearinghouse (NOHIC) distributes
a poster titled, "Detecting Oral Cancer: A Guide for Health Care Professionals,"
which offers a step-by-step pictorial guide on how to conduct the exam.
Additionally, NOHIC has developed a companion slide show based on the poster.
The slide show is distributed with a script and copies of the poster, patient
education pamphlet titled, "What You Need to Know About Oral Cancer,"
and 'tips card' that lists signs and symptoms of the disease. NOHIC sends
these materials to dentists, physicians, nurse practitioners, and other
health care providers around the country.