Education
1992       B.S.             McGill University
1996       D.D.S.          McGill University

Clinical Specialties
Oral and maxillofacial pathology

Research Area of Interest
Oral squamous cell carcinoma, human papillomavirus

Research Summary
Oral squamous cell carcinoma (OSCC) is a multifactorial disease in which, both, extrinsic and intrinsic factors play a role in initiation and propagation of the tumors. While OSCC is not an inherited disease, there are a number of genetic diseases in which the risk for developing OSCC is significantly elevated. Moreover, many of these same systemic diseases are characterized by chromosomal instability, whereby, over time, the cells spontaneously accumulate gross and micro-molecular genomic aberrations, including changes in DNA copy number, non-reciprocal translocations, end-to-end chromosomal fusion and deletions. Thus, it is likely that individuals with these syndromes develop OSCC as a consequence of the intrinsic genomic instability.

Dyskeratosis congenita is an example of an heritable disease in which the risk for developing oral cancer appears to be significantly elevated. Affected individuals manifest initially with a triad of mucocutaneous findings, including abnormal skin pigmentation, dystrophic nails, and oral leukoplakia. Premature bone marrow failure, a predisposition to various epithelial and hematologic cancers and signs of premature aging are also features typically associated with this rare disorder. Over time, an estimated one third of the oral lesions will transform to OSCC. The genes responsible for the some of the X-linked recessive and autosomal dominant forms of dyskeratosis congenita have been recently identified. Both genes are key components of the telomerase ribonucleoprotein complex, and thus play a role in telomere maintenance. Telomeres are nucleoprotein structures found at the ends of chromosomes that function to protect chromosomal integrity during cell division. With each cell division, telomeres become progressively shorter, thus increasing susceptibility to various chromosomal abnormalities. In patients with DC, there is accelerated shortening of telomeres thereby greatly increasing susceptibility of the cells to genomic instability. However, a growing body of evidence now suggests that loss of telomere maintenance and chromosomal instability are characteristic of, and also play a role in, the development and clinical progression of sporadic OSCC. Thus using DC as a model for our studies, our lab is currently in the process of determining the mechanisms by which the genes responsible for DC also play a role in the pathogenesis of sporadic OSCC.

Selected Publications