In this study the investigators are conducting research to determine whether a new optical device using polarization reflectance spectroscopy can help doctors or dentists identify abnormalities in the mouth that require follow-up. To establish this, measurements are needed from a large number of individuals with different abnormalities in their mouth.

The investigators believe the proposed approach has potential to improve and enable mass screening for precancerous and early cancers of the oral cavity by improving the predictive value of oral cavity exams, particularly for less experienced practitioners.

The information from this study will be compared to results from the pathology report of the tissue taken from your mouth.

Hypothesis:

1. Polarized reflectance spectroscopy can distinguish high-risk oral lesion from normal and reactive oral lesions.
2. Polarized reflectance spectroscopy can capture low-grade oral lesions that have characteristics associated with a high risk of progression to cancer.

The clinician will place a fiber-optic probe designed to measure the polarized reflectance spectra over the visible optical region on a site of interest in the subject's mouth, including lesional mucosa, normal adjacent and contralateral mucosa. The site for placement of the probe will be determined by the examiner, an experienced Oral Pathologist. The probe examination will take no more than 15 minutes in addition to the subject's appointment time for their routine visits.

A 4um unstained tissue section from surgery or biopsy, part of their scheduled care, will be requested for quantitative histological analysis. The morphometric parameters obtained from polarized reflectance measurements will be compared with the histology and quantitative pathology (nuclear phenotype score) from the tissue sections from the lesion. The collected spectra data from normal looking areas from adjacent normal looking mucosa and contralateral mucosa will be used to determine patient to patient variation in the polarized reflectance of oral mucosa.

Inclusion Criteria:

• You attend the Dental Department at the British Columbia Cancer Agency
• You have an abnormal lesion in the mouth
• You fully understand the study and give your informed consent to participate as demonstrated by signing this consent form

Exclusion Criteria:

• You are under the age of 18 years.