Epidemiology and natural history of oral human papillomavirus infections: a review.

The aim of this literature review is to explore current findings relating to the natural history of the acquisition and persistence of oral human papillomavirus (HPV) infection, as well as to identify the risk factors and populations at risk associated with oral HPV infections.Non UBCDentistry, Faculty ofUnreviewedGraduat

Histological clonal change - A feature for dysplasia diagnosis

Aims: Histological diagnostic criteria are used for the assessment of the degree of dysplasia and hence the risk of cancer progression for premalignant lesions. Clonal changes in the form of hyperorthokeratosis and hyperchromasia that are sharply demarcated from adjacent areas are not currently part of the criterion for dysplasia diagnosis. The objective of this study was to determine whether such clonal change should be regarded as a diagnostic feature for dysplasia. The following histological conditions were used to define such change: (1) hyperorthokeratosis; (2) hyperchromatism but no other features of dysplasia; (3) sharp margin demarcation from adjacent area by both the hyperorthokeratosis and hyperchromasia (clonal change), and (4) no prominent rete ridges, marked acanthosis or heavy inflammation. Lesions fitting these criteria were termed orthokeratotic lesions with no dysplasia. Methods: Patients from a population-based longitudinal study with more than 10 years of follow up were analyzed. Of the 214 patients with primary oral premalignant lesions, 194 had mild or moderate dysplasia (dysplasia group) and 20 fit the criteria for orthokeratotic lesions without dysplasia (orthokeratotic with no dysplasia group). The two groups were compared for their cancer risks using clinical (site and toluidine blue), histological (nuclear phenotype score), and molecular criteria (loss of heterozygosity) and by outcome (progression). Results and conclusions: The lesions from orthokeratotic with no dysplasia group showed a similar cancer risk (clinical, histological and molecular risk) and time to progression as the dysplastic lesions. We recommend that the clonal change should be included as a criterion for dysplasia diagnosi

Genomic imbalances in precancerous tissues signal oral cancer risk

Oral cancer develops through a series of histopathological stages: through mild (low grade), moderate, and severe (high grade) dysplasia to carcinoma in situ and then invasive disease. Early detection of those oral premalignant lesions (OPLs) that will develop into invasive tumors is necessary to improve the poor prognosis of oral cancer. Because no tools exist for delineating progression risk in low grade oral lesions, we cannot determine which of these cases require aggressive intervention. We undertook whole genome analysis by tiling-path array comparative genomic hybridization for a rare panel of early and late stage OPLs (n = 62), all of which had extensive longitudinal follow up (>10 years). Genome profiles for oral squamous cell carcinomas (n = 24) were generated for comparison. Parallel analysis of genome alterations and clinical parameters was performed to identify features associated with disease progression. Genome alterations in low grade dysplasias progressing to invasive disease more closely resembled those observed for later stage disease than they did those observed for non-progressing low grade dysplasias. This was despite the histopathological similarity between progressing and non-progressing cases. Strikingly, unbiased computational analysis of genomic alteration data correctly classified nearly all progressing low grade dysplasia cases. Our data demonstrate that high resolution genomic analysis can be used to evaluate progression risk in low grade OPLs, a marked improvement over present histopathological approaches which cannot delineate progression risk. Taken together, our data suggest that whole genome technologies could be used in management strategies for patients presenting with precancerous oral lesions.Computer Science, Department ofDentistry, Faculty ofMedicine, Faculty ofOral Biological and Medical Sciences (OBMS), Department ofPathology and Laboratory Medicine, Department ofScience, Faculty ofNon UBCReviewedFacult

Characterization of Epithelial Progenitors in Normal Human Palatine Tonsils and Their HPV16 E6/E7-Induced Perturbation

Human palatine tonsils are oropharyngeal lymphoid tissues containing multiple invaginations (crypts) in which the continuity of the outer surface epithelium is disrupted and the isolated epithelial cells intermingle with other cell types. We now show that primitive epithelial cells detectable in vitro in 2D colony assays and in a 3D culture system are CD44+NGFR+ and present in both surface and crypt regions. Transcriptome analysis indicated a high similarity between CD44+NGFR+ cells in both regions, although those isolated from the crypt contained a higher proportion of the most primitive (holo)clonogenic cells. Lentiviral transduction of CD44+NGFR+ cells from both regions with human papillomavirus 16-encoded E6/E7 prolonged their growth in 2D cultures and caused aberrant differentiation in 3D cultures. Our findings therefore reveal a shared, site-independent, hierarchical organization, differentiation potential, and transcriptional profile of normal human tonsillar epithelial progenitor cells. They also introduce a new model for investigating the mechanisms of their transformation