Mutated and wild-type p53 expression and HPV integration in proliferative verrucous leukoplakia and oral squamous cell carcinoma

Molecular landscape of proliferative verrucous leukoplakia: a systematic review

Proliferative verrucous leukoplakia (PVL) is a rare oral potentially malignant disorder characterised by multifocal origin and unpredictable long-term evolution to oral squamous cell carcinoma (OSCC) or oral verrucous carcinoma (OVC). Currently no predictive biomarkers are in clinical use. We aimed to explore the genomic profile of PVL. A total of 685 cases in 26 studies were included in this review. Genomic data were presented in 15% of studies and biomarker analysis was reported in 85% of studies. At first clinical presentation, PVL is characterised by a high loss of heterozygosity (LOH), similar to OSCC, and low copy number alterations (CNA). As these progress, more CNAs and mutations in CDKN2A and alterations to ELAVL1 expression are noted, but no TP53 mutations are identified. There is significantly lower LOH at 17p in early PVL compared with OSCC (p = 0.037). Deletions in chromosomal loci 17q12, 5q31.1 and amplifications in 7q11.2, 7q22 are shared between early lesions and OVC. PVL shows CNAs at 11q31. WNT signalling pathway genes (SUZ12, CTTN and FOLR3) are enriched in CN-altered regions. PVL stroma shows significantly lower α-SMA and higher CD34 expression than OVC and OSCC. The exact genomic landscape is currently unclear, and further studies are necessary to unravel this mystery.

Utilization of p53 and p16 Immunohistochemistry in the Classification of Human Papillomavirus-Associated, p53 Wild-Type, and p53 Abnormal Oral Epithelial Dysplasia

p53 immunohistochemistry (IHC) has recently been shown to be a clinically useful marker for predicting risk of progression to invasive squamous cell carcinoma in oral epithelial dysplasia (OED). The literature supports the use of p53 IHC as a marker to identify TP53 mutation in in situ and invasive vulvar lesions and as a surrogate marker for high-risk human papillomavirus (HPV) infection, but there is little documentation for similar use in OED. The purpose of this study was to determine whether p53 IHC is a reliable surrogate marker for detecting both TP53 mutation and high-risk HPV infection in OED. We studied 57 cases of OED (11 mild, 18 moderate, and 28 severe), and all were stained for p16 and p53 IHC. High-risk HPV RNA in situ hybridization (ISH) was performed in selected cases (all p16-positive cases and all OED showing abundant apoptotic cells and karyorrhectic cells; N = 27). Targeted next-generation sequencing (NGS) was performed in 33 p16-negative cases and all high-risk HPV RNA ISH-negative cases (N = 36). We identified 21 cases with p53 basal sparing patterns (mid-epithelial and markedly reduced [null-like]), 14 cases with p53 wild-type patterns (scattered basal and patchy basal/parabasal), and 22 cases with p53 abnormal patterns (18 overexpression, 3 null, and 1 novel cytoplasmic pattern). Among cases with p53 basal sparing patterns, 20 were positive for p16 (20/21, 95%), and all were positive for high-risk HPV RNA ISH (21/21, 100%). The 36 sequenced cases had IHC patterns concordant with TP53 mutation status in 92% (33/36) of lesions. This study demonstrates that p53 IHC expression patterns are sensitive and specific for detection of both high-risk HPV infection and TP53 mutation. Coupled with selective p16 IHC testing, this IHC panel can accurately subclassify OED into HPV-associated, p53 wild-type (conventional), and p53 abnormal OED.

Comprehensive Immunoprofiling of High-Risk Oral Proliferative and Localized Leukoplakia

Oral leukoplakia is common and may, in some cases, progress to carcinoma. Proliferative leukoplakia is a progressive, often multifocal subtype with a high rate of malignant transformation compared with the more common localized leukoplakia. We hypothesized that the immune microenvironment and gene expression patterns would be distinct for proliferative leukoplakia compared with localized leukoplakia. We summarize key clinicopathologic features among proliferative leukoplakia and localized leukoplakia and compare cancer-free survival (CFS) between subgroups. We analyze immunologic gene expression profiling in proliferative leukoplakia and localized leukoplakia tissue samples (NanoString PanCancer Immune Oncology Profiling). We integrate immune cell activation and spatial distribution patterns in tissue samples using multiplexed immunofluorescence and digital image capture to further define proliferative leukoplakia and localized leukoplakia. Among N = 58 patients (proliferative leukoplakia, n = 29; localized leukoplakia, n = 29), only the clinical diagnosis of proliferative leukoplakia was associated with significantly decreased CFS (HR, 11.25; P < 0.01; 5-year CFS 46.8% and 83.6% among patients with proliferative leukoplakia and localized leukoplakia, respectively). CD8⁺ T cells and T regulatory (Treg) were more abundant among proliferative leukoplakia samples (P < 0.01) regardless of degree of epithelial dysplasia, and often colocalized to the dysplasia-stromal interface. Gene set analysis identified granzyme M as the most differentially expressed gene favoring the proliferative leukoplakia subgroup (log₂ fold change, 1.93; P _adj < 0.001). Programmed death ligand 1 (PD-L1) was comparatively overexpressed among proliferative leukoplakia samples, with higher (>5) PD-L1 scores predicting worse CFS (P _adj < 0.01). Proliferative leukoplakia predicts a high rate of malignant transformation within 5 years of diagnosis. A prominent CD8⁺ T-cell and Treg signature along with relative PD-L1 overexpression compared with localized leukoplakia provides strong rationale for PD-1/PD-L1 axis blockade using preventative immunotherapy.

Significance

This is the first in-depth profiling effort to immunologically characterize high-risk proliferative leukoplakia as compared with the more common localized leukoplakia. We observed a notable cytotoxic T-cell and Treg signature with relative overexpression of PD-L1 in high-risk proliferative leukoplakia providing a strong preclinical rationale for investigating PD-1/PD-L1 axis blockade in this disease as preventative immunotherapy.

Oral Proliferative Verrucous Leukoplakia: Progression to Malignancy and Clinical Implications. Systematic Review and Meta-Analysis

Simple Summary

Proliferative verrucous leukoplakia (PVL) was recognized in 2005 by the World Health Organization as a rare subtype of true oral leukoplakia, with unknown etiology. Since its first description in 1985, several diagnostic criteria have been proposed over the years. The aim of this systematic review is to investigate the percentage of patients diagnosed with proliferative verrucous leukoplakia who progressed to oral verrucous carcinoma (OVC) or conventional oral squamous cell carcinoma (OSCC).

Abstract

Aim: The aim of the present systematic review was to investigate the risk of malignant transformation of proliferative verrucous leukoplakia (PVL). Materials and Methods: the search was carried out using a combination of terms (leukoplakia OR leucoplakia) AND (multifocal OR proliferative) on the following databases: PubMed, Scopus, Web of Science (WOS Core Collection), Cochrane Library, selecting only articles published since 1985 and in the English language. Demographic, disease-related, and follow-up data extracted from the studies included in the qualitative synthesis were combined. Weighted means ± standard deviations were calculated for continuous variables, while categorical variables were reported as frequencies and percentages. Dichotomous outcomes were expressed as odd ratios (ORs) with 95% confidence intervals (CIs). Odd ratios for individual studies were combined using a random-effects meta-analysis, conducted using Review Manager 5.4 Software (Cochrane Community, Oxford, England). Results: twenty-two articles were included, with a total of 699 PVL patients, undergoing a mean follow-up of 7.2 years. Sixty-six percent of patients were females, with a mean age of 70.2 years, and 33.3% were males, with a mean age of 59.6 years. Most patients were non-smokers and non-alcohol users, and the gingiva/alveolar ridge mucosa was the most involved anatomical site by both PVL appearance and malignant transformation. A total of 320 PVL patients developed oral verrucous carcinoma (OVC) or conventional oral squamous cell carcinoma (OSCC) because of malignant transformation of PVL lesions (45.8%). A statistically significant 3.8-fold higher risk of progression to conventional OSCC was found compared to OVC in PVL patients, with women being 1.7 times more likely to develop oral cancer than men, as a consequence of PVL progression. Moreover, a statistically significant higher likelihood of developing conventional OSCC in female PVL patients than in males was found. In 46.5% of patients with PVL malignant transformation, multiple carcinomas, in different oral sites, occurred during follow-up. Conclusions: PVL is an aggressive lesion, which, in a high percentage of cases (almost 50%), undergoes malignant transformation, mainly toward OSCC. The female gender is most affected, especially in the elderly, with a negative history for alcohol and tobacco consumption.

Immune expression profile identification in a group of proliferative verrucous leukoplakia patients: a pre-cancer niche for oral squamous cell carcinoma development

OBJECTIVES

To explore the pathophysiology of proliferative verrucous leukoplakia, a rare oral disorder that exhibits high rates of recurrence and malignant transformation, through a RNAseq case-control study.

MATERIAL AND METHODS

We obtained oral biopsies from 10 patients with verrucous leukoplakia lesions and from the mucosa of 5 healthy individuals for sequencing using RNAseq technology. Using bioinformatic methods, we investigated gene expression and enrichment differences between patients both with and without the disorder. We applied network biology methods to investigate functional relations among those genes that were differentially deregulated.

RESULTS

We detected 140 differentially expressed genes with distinct roles in immune surveillance, tissue and organ morphogenesis, development, and organization. Of these 140 genes, 111 have been previously described as cancer expression biomarkers, being oral squamous cell carcinoma the most represented type of cancer among them. Of these 140 genes, 26 were prioritized for further investigation as biomarkers using larger sample sizes.

CONCLUSIONS

The gene expression patterns of healthy and unhealthy patients differed in 140 genes whose deregulation has a functional impact on normal functioning of the immune system. This immune expression profile provides a plausible hypothesis to explain the transformation to oral squamous cell carcinoma observed in 6 of the 10 assayed cases.

CLINICAL RELEVANCE

By determining the molecular bases of the proliferative verrucous leukoplakia disorder and identifying early biomarkers of malignancy, this can allow us to develop new treatment strategies.

Correlation of p53 Expression with Histopathological and Immunohistochemical Features of Human Papillomavirus in Oral Leukoplakia

Background

Oral cancer is strongly associated with the habit of tobacco chewing, alcohol, and betel quid consumption in India. However, sometimes, majority of the population develop oral cancer without exposure to these risk factors and are sometimes cautious about their fitness, suggesting that additional causes such as genetic predisposition, diet, and viral agents may be associated which need to explored.

Aims and Objectives

The aim of this study was to establish a possible correlation between clinical types of leukoplakia with their histopathological features of high-risk human papillomavirus (HPV) infection and the presence or absence of HPV and expression of p53through immunohistochemistry (IHC).

Materials and Methods

Sample comprised of 40 cases of leukoplakia and 10 cases as control group. Three sections were prepared from each biopsy and subjected to IHC and hematoxylin and eosin (H and E) stain, respectively. IHC-stained slides were used to evaluate the expression of p53 and HPV and then correlated with the features of HPV infection using H and E staining. Chi-square test with a statistical analysis software package (SPSS software Version 20.0) was used.

Observation and Results

The P value for p53 against HPV (IHC) was 0.012, which indicates a significant difference between positivity proportion of P53 and HPV (IHC), whereas the P value for koilocyte and HPV (IHC) is 0.311, which is nonsignificant and indicates no significance of difference between proportion of positivity between koilocyte and HPV (IHC).

Conclusion

The expression of p53 was proportionally significant to the expression of positivity of HPV, but there was no significant association between koilocyte and p53 expression.

Molecular, genomic and mutational landscape of oral leukoplakia

Oral leukoplakia (OLK) and its more aggressive clinical variant proliferative verrucous leukoplakia (PVL) remain enigmatic disorders clinically and histopathologically. Despite decades of research into both, there has been only incremental advancement in our understanding of their aetiology and pathogenesis and only minimal improvement in effective management strategies. Currently, no specific prognostic genetic or molecular marker has been reported for leukoplakia. There is, however, an emerging body of evidence characterising the genomic and transcriptomic profile of OLK. Regardless of the significance of cellular and architectural features of OLK and PVL, it is clear from studies reported in this review that new emerging evidence points to the presence of premalignant molecular subtypes of leukoplakia which require further investigation. This up-to-date review explores the contemporary genomic, transcriptomic and mutational landscape of leukoplakia broadly, discusses concepts that may not be widely recognised or accepted and purposefully highlights studies with juxtaposed findings in an effort to challenge dogma. It also highlights the urgent need for a concerted international effort of original collaborative research which will only occur by pooling collective efforts, resources and intellect to define the molecular fingerprint of this enigmatic disorder, in the hope it will better inform diagnosis, stratification and treatment.

Association of Human Papillomavirus With Oral Lichen Planus and Oral Leukoplakia: A Meta-analysis

OBJECTIVES

To estimate the association of human papillomavirus (HPV) infection with oral lichen planus (OLP) and oral leukoplakia (OLK), and determine risk cofactors.

STUDY DESIGN

Seven databases were searched for case-control or cross-sectional studies of OLP and OLK with healthy controls, published between 1976 and 2020. The Meta package of R software was applied to calculate the pooled odds ratios (OR) and 95% confidence interval (CI).

RESULTS

Thirty-six articles were finally included. OLP and OLK cases had a higher association with HPV infection than controls (OLP: OR: 4.91, 95% CI: 2.76-8.72; OLK: OR: 2.51, 95% CI: 1.55-4.07). In subgroup analyses, the OR of HPV infection was higher with erosive lesions than with nonerosive lesions (OLP: OR: 5.36 and 3.47, respectively; OLK: OR: 3.34 and 3.21, respectively). Oral lesions were more strongly associated with HPV16/18 than with HPV6/11 (OLP: OR: 7.84 and 1.42, respectively; OLK: OR: 6.05 and 1.87, respectively) and varied by geographic region (OLP: OR: 4.01-7.02; OLK: OR: 1.46-27.13).

CONCLUSIONS

Oral HPV infection, particularly infection with HPV 16/18, was strongly associated with OLP and OLK. Risk cofactors included erosive lesions and geographic region.

Clinicopathologic analysis of verrucous hyperplasia, verrucous carcinoma and squamous cell carcinoma as part of the clinicopathologic spectrum of oral proliferative verrucous leukoplakia: A literature review and analysis

OBJECTIVE

Proliferative verrucous leukoplakia is classified as a potentially malignant disorder because of its high rate of malignant transformation. PVL progresses in a series of clinical stages where the early stage represents multiple, multifocal leukoplakias with a high recurrence rate. The intermediate and late stages are clinically exophytic lesion, diagnosed microscopically as verrucous hyperplasia that often progresses into verrucous carcinoma and/or squamous cell carcinoma. There is no single histologic definition and the diagnosis is retrospective following observed progression of the disorder. The goal of the current study was to conduct a literature review and analysis of PVL in the later stages to gain further knowledge on their clinicopathologic features.

DATA SOURCES

Medline's PubMed and Google Scholar were searched for adequately documented cases from 1985 to 2018. References of published articles were searched for additional cases.

REVIEW METHODS

Overall, 57 manuscripts were analyzed. 35/57 manuscripts provided adequate data on the clinicopathologic features in the premalignant and malignant stages.

RESULTS

Malignant transformation rate was 50% (average of 57 months). Gingiva, palate and buccal mucosa were the most common locations. Clinicopathologic features included; well differentiated carcinoma (78%), perineural invasion (3%), lymph node metastasis (4%); distant metastasis (0%), average duration of illness (65 months), DOD-dead of disease (44%). Moderate dysplasia, severe dysplasia and carcinoma in situ were exceptionally uncommon in the premalignant stages (0.8%).

CONCLUSION

Prognostic factors such as perineural invasion, lymph node metastasis and distant metastasis were uncommon occurrences which may have practical implications on treatment. Further studies are needed to substantiate our findings.

Oral keratosis of unknown significance shares genomic overlap with oral dysplasia

OBJECTIVES

To identify molecular characteristics of keratosis of unknown significance and to nominate pathways of molecular progression to oral cancer. Our work could provide a rationale for monitoring and treating these lesions definitively.

METHODS

Patients with oral leukoplakia were eligible for our prospective observational study. We correlated alterations in cancer-associated genes with clinical and histopathologic variables (keratosis of unknown significance vs. moderate-to-severe dysplasia) and compared these alterations to a previously molecularly characterized oral cancer population.

RESULTS

Of 20 enrolled patients, 13 (65%) had evidence of keratosis of unknown significance, while seven (35%) had dysplasia. Nine patients (45%) developed oral cancer (4/13 with keratosis of unknown significance, 5/7 with dysplasia). At a median follow-up of 67 (range 22-144) months, median overall survival was significantly shorter for patients with dysplasia (hazard ratio 0.11, p = .02). KMT2C and TP53 alterations were most frequent (75% and 35%, respectively). There were molecular similarities between keratosis of unknown significance and dysplasia patients, with no significant differences in mutational frequency among genes with ≥15% rate of alteration.

CONCLUSIONS

Among patients with leukoplakia, both patients with keratosis of unknown significance and patients with dysplasia developed oral cancer. Molecular alterations between these two groups were similar at this sample size.

A Retrospective 20-Year Analysis of Proliferative Verrucous Leukoplakia and Its Progression to Malignancy and Association with High-risk Human Papillomavirus

Proliferative verrucous leukoplakia (PVL) is defined as an aggressive, relentless and recalcitrant form of leukoplakia that has a high propensity for malignant transformation. The aim of this study was to evaluate the malignant potential of PVL and determine its possible association with high-risk human papillomavirus (HPV). Twenty cases with a clinical and biopsy proven diagnosis of PVL were collected from the University of Florida Oral Medicine clinic database. Immunohistochemistry was performed to evaluate the expression of p16INK4A and p53 genes in the PVL lesions. The lesions were also tested for high-risk HPV by DNA in-situ hybridization. The average age of the patients at the time of first biopsy was 62.7 years. Most patients had multiple sites of involvement, gingiva being the most common location. The lesions progressed to malignancy in approximately 50% of patients. The expression of p16INK4A gene was considered negative, with at least a 50-65% immunoreactivity observed in only three cases that progressed to malignancy. No expression of high-risk HPV was detected, whereas p53 staining was positive in less than 25% of the cells demonstrating gene expression. No definite association between PVL and high-risk HPV infection could be established. Due to the high transformation potential of PVL, early recognition with aggressive treatment, including multiple biopsies, and continued close clinical follow-up, remain the mainstay of favorable management of this condition.

Proliferative leukoplakia: Proposed new clinical diagnostic criteria

OBJECTIVE

We aimed to characterize proliferative verrucous leukoplakia (PVL) from a clinical and histopathological standpoint and suggest an updated classification.

SUBJECTS AND METHODS

Records of patients seen at three oral medicine centers with a clinical diagnosis of PVL were reviewed for clinical and histopathological features and malignant transformation (MT).

RESULTS

There were 42 patients (median age: 69 years [range: 36-88]; 35 females). 12.2% were current smokers. Family history of cancer was present in 43.7% of patients. Partial demarcation of lesion margins was present in 31.3% of lesions, followed by verrucous (27.5%), smooth (22.7%) erythematous (22.3%), and fissured (18.3%) appearance. Large and contiguous and multisite and non-contiguous lesions comprised 57.1% (24/42) and 35.7% (15/42) of PVL cases, respectively. 19.1% had prominent erythema (erythroleukoplakia). The most common histopathological diagnosis at first visit was hyperkeratosis without dysplasia (22/42; 56.4%). MT occurred in 71.4% patients after a median of 37 months [range: 1-210] from initial visit; erythroleukoplakia exhibited MT in 100% of cases.

CONCLUSION

The generic term "proliferative leukoplakia (PL)" may be more appropriate than PVL because 18.3% were fissured and 22.7% erythematous. We also propose the term proliferative erythroleukoplakia to more accurately describe the subset of PL with prominent erythema, which had the highest MT rate.

Proliferative verrucous leukoplakia: diagnosis, management and current advances

Introduction

Proliferative verrucous leukoplakia is a multifocal and progressive lesion of the oral mucosa, with unknown etiology, and commonly resistant to all therapy attempts with frequent recurrences. It is characterized by a high rate of oral squamous cell carcinoma and verrucou carcinoma transformations.

Objective

To analyze the studies about Proliferative verrucous leukoplakia and develop a concise update.

Methods

A Pubmed search identifying studies (laboratory research, case series and reviews of literature) that examined patients with Proliferative verrucous leukoplakia was realized.

Results

There are not enough studies about Proliferative verrucous leukoplakia in the literature. The few found studies not present a consensus about its etiology and diagnosis criteria. Although several treatment strategies have been proposed, most of them still show a high recurrence rate.

Conclusion

More research about Proliferative verrucous leukoplakia is necessary to understand and treat this disease.

Low expression of angiotensinogen and dipeptidyl peptidase 1 in saliva of patients with proliferative verrucous leukoplakia

AIM

To elucidate the profile of the salivary proteome.

METHODS

Unstimulated whole mouth saliva was collected from 30 volunteers [15 proliferative verrucous leukoplakia (PVL) patients and 15 controls] and proteins were submitted for mass spectrometry-based proteomics using the discovery approach, followed by analyses of variance and logistic regression tests.

RESULTS

A total of two hundred and eighty-three proteins were confidently identified in saliva. By combining two low abundance proteins from the PVL group, angiotensinogen (AGT) and dipeptidyl peptidase 1 (DPP1), a model for group differentiation was built with a concordance index of 94.2%, identifying both proteins as potential etiologic biomarkers for PVL.

CONCLUSION

This study suggests that both AGT and DPP1 may be involved in developmental mechanisms of PVL.

[Proliferative verrucous leukoplakia: Three cases and literature review]

BACKGROUND

The aim of this study was to collect epidemiological, aetiopathogenic, clinical, histological and therapeutic data concerning proliferative verrucous leucoplakia (PVL) and to report three new cases.

PATIENTS AND METHODS

A literature review performed using the Medline database enabled us to collate 39 studies involving 607 cases. Three new cases were added.

RESULTS

PVL is a rare disease characterized by extensive and multifocal oral leucoplakic lesions. Its histological pattern depends on the stage of the disease: hyperkeratosis, verrucous hyperplasia, verrucous carcinoma and squamous cell carcinoma. The aetiopathogenesis of PVL is poorly understood and there is no clear consensus concerning therapy. Malignant transformation occurs in over 50 % of cases.

DISCUSSION

Diagnosis of PVL is difficult because of the presenting signs, which can be mistaken for those of other diseases. Management may be complicated and long-term follow-up is essential.

Oral proliferative verrucous leucoplakia: are there particular features for such an ambiguous entity? A systematic review

Proliferative verrucous leucoplakia (PVL) is a distinct, particularly aggressive form of oral leucoplakia. Given the low prevalence of PVL, data are sparse and are mostly from case reports, case series and only a few case-control studies, meaning that the literature is able to provide only weak evidence. The present systematic literature review aims to collate the available evidence on the following issues: patient demographics, aetiology, lesion location(s), malignant potential, location and histopathological features of transformed lesions, disease-specific survival rates and treatment response. Electronic databases were searched for studies in the English language reporting original data from at least 10 patients with PVL on the target issues of the present review. The retrieved data were merged and a descriptive analysis performed. The 20 studies selected indicated that PVL does not seem to be correlated with the major risk factors for oral carcinoma (tobacco, alcohol and/or areca nut/betel leaf chewing). The disorder affects mainly adult/elderly women and has a very high malignant transformation rate, particular site distribution and particular location and histopathological features of transformed lesions. The present results may be limited by some articles being unintentionally excluded as they were not found during the electronic search, a lack of worldwide accepted diagnostic criteria for PVL, and overlapping data from multiple studies performed in a limited number of centres. Despite these potential drawbacks, the present results demonstrate that PVL does have particular features.

Oral squamous cell carcinoma associated with proliferative verrucous leukoplakia compared with conventional squamous cell carcinoma--a clinical, histologic and immunohistochemical study

OBJECTIVE

Proliferative verrucous leukoplakia (PVL), a potentially malignant disorder, often undergoes malignant transformation to oral squamous cell carcinoma. The aim of our study was to document and compare the histologic, immunohistochemical, and clinical features and the survival rates of carcinoma arising in patients with PVL (p-scca) with conventional squamous cell carcinoma (c-scca) in order to determine if p-scca should be categorized as a separate clinical entity.

MATERIALS AND METHODS

A retrospective review of 11 patients with PVL, 38 with p-scca tumors and 49 with c-scca tumors: buccal mucosa (n = 28) and gingiva or palate (n = 21). Immunohistochemistry was performed by using antibodies directed against p16, p53, and ki67.

RESULTS

P-scca had lower clinical stage (P = .0001), smaller tumor size (P = .0033), no lymph node metastasis (P = .0002) or distant metastasis (P = .05), and better short term (P = .03), but not long term (P = .12) survival. Microscopically, p-scca tumor thickness was significantly less (P = .0001). P-53 overexpression was more common in p-scca (P = .0043) but not ki67 or p16 overexpression.

CONCLUSIONS

P-scca, compared with c-scca, presented with significantly better prognostic factors and short-term survival rates and longer duration of disease. Our results suggest that p-scca may represent a distinct entity, which may have practical implications when deciding on treatment. Further studies on a larger cohort of patients are recommended.

Proliferative verrucous leukoplakia: recognition and differentiation from conventional leukoplakia and mimics

The majority of conventional leukoplakia remains constant and only a subset progress to high-grade dysplasia or invasive carcinoma. A less recognized form known as proliferative verrucous leukoplakia (PVL) represents a unique progressive and elusive variant. Identifying patients with this form can only be achieved through the keen clinical observation of the temporal gross and histologic progression in individual patients with squamous cell carcinoma. The difficulty in the early diagnosis of PVL stems from the overlapping clinical and pathologic features with conventional multifocal leukoplakia with dysplasia. We present the current view on the clinicopathologic and biological characteristics of PVL and discuss their diagnosis, differential diagnosis, and management.

Proliferative verrucous leukoplakia: an elusive disorder

Proliferative Verrucous Leukoplakia (PVL) is a multifocal form of progressive leukoplakia with a high rate of malignant transformation that requires early recognition by oral health care providers for proper management.

BACKGROUND AND PURPOSE

PVL will frequently appear as an innocuous white lesion or lesions that can easily be overlooked or considered clinically insignificant, yet it has a high rate of malignant transformation. There is limited in-depth knowledge about the pathobiology of PVL. Oral health care providers lack familiarity with this lesion; consequently the intent of this article is to increase awareness of the clinical aspects of PVL.

METHODS

Case reports, case series and review articles provide a profile of PVL.

CONCLUSION

It is essential that health care providers performing intraoral examinations are aware that PVL is a distinct and rare form of multifocal oral leukoplakia. PVL commonly affects females above the age of 62. Currently, little is known about its etiopathogenesis. Additionally, no specific treatment modality has proven to be effective in aborting its progression. Because of its high recurrence potential and relentless progression to squamous cell carcinoma, all recurrent and multifocal white lesions of the oral cavity should be viewed with suspicion.

Evidences suggesting involvement of viruses in oral squamous cell carcinoma

Oral cancer is one of the most common cancers and it constitutes a major health problem particularly in developing countries. Oral squamous cell carcinoma (OSCC) represents the most frequent of all oral neoplasms. Several risk factors have been well characterized to be associated with OSCC with substantial evidences. The etiology of OSCC is complex and involves many factors. The most clearly defined potential factors are smoking and alcohol, which substantially increase the risk of OSCC. However, despite this clear association, a substantial proportion of patients develop OSCC without exposure to them, emphasizing the role of other risk factors such as genetic susceptibility and oncogenic viruses. Some viruses are strongly associated with OSCC while the association of others is less frequent and may depend on cofactors for their carcinogenic effects. Therefore, the exact role of viruses must be evaluated with care in order to improve the diagnosis and treatment of OSCC. Although a viral association within a subset of OSCC has been shown, the molecular and histopathological characteristics of these tumors have yet to be clearly defined.

Urban legends series: oral leukoplakia

To date, the term oral leukoplakia (OL) should be used to recognize 'predominantly white plaques of questionable risk, having excluded (other) known diseases or disorders that carry no increased risk of cancer'. In this review, we addressed four controversial topics regarding oral leukoplakias (OLs): (i) Do tobacco and alcohol cause OLs?, (ii) What percentage of OLs transform into oral squamous cell carcinoma (OSCC)?, (iii) Can we distinguish between premalignant and innocent OLs?, and (iv) Is proliferative verrucous leukoplakia (PVL) a specific entity or just a form of multifocal leukoplakia? Results of extensive literature search suggest that (i) no definitive evidence for direct causal relationship between smoked tobacco and alcohol as causative factors of OLs, (ii and iii) the vast majority of OLs follow a benign course and do not progress into a cancer, and no widely accepted and/or validated clinical and/or biological factors can predict malignant transformation, and (iv) the distinction between multifocal/multiple leukoplakias and PVL in their early presentation is impossible; the temporal clinical progression and the high rate of recurrences and development of cancer of PVL are the most reliable features for diagnosis.

Human papillomaviruses in oral carcinoma and oral potentially malignant disorders: a systematic review

OBJECTIVES

Human papillomavirus (HPV) in oral carcinoma (OSCC) and potentially malignant disorders (OPMD) is controversial. The primary aim was to calculate pooled risk estimates for the association of HPV with OSCC and OPMD when compared with healthy oral mucosa as controls. We also examined the effects of sampling techniques on HPV detection rates.

METHODS

Systematic review was performed using PubMed (January 1966-September 2010) and EMBASE (January 1990-September 2010). Eligible studies included randomized controlled, cohort and cross-sectional studies. Pooled data were analysed by calculating odds ratios, using a random effects model. Risk of bias was based on characteristics of study group, appropriateness of the control group and prospective design.

RESULTS

Of the 1121 publications identified, 39 cross-sectional studies met the inclusion criteria. Collectively, 1885 cases and 2248 controls of OSCC and 956 cases and 675 controls of OPMD were available for analysis. Significant association was found between pooled HPV-DNA detection and OSCC (OR = 3.98; 95% CI: 2.62-6.02) and even for HPV16 only (OR = 3.86; 95% CI: 2.16-6.86). HPV was also associated with OPMD (OR = 3.87; 95% CI: 2.87-5.21). In a subgroup analysis of OPMD, HPV was also associated with oral leukoplakia (OR = 4.03; 95% CI: 2.34-6.92), oral lichen planus (OR = 5.12; 95% CI: 2.40-10.93), and epithelial dysplasia (OR = 5.10; 95% CI: 2.03-12.80).

CONCLUSIONS

The results suggest a potentially important causal association between HPV and OSCC and OPMD.

Proliferation and apoptosis markers in oral submucous fibrosis

BACKGROUND

Premalignant/potentially malignant-oral lesions and conditions such as oral submucous fibrosis are known to transform into oral cancer. The malignant transformation is often associated with changes at the genetic level that in turn is reflected by the altered expression of proteins related to cell cycle, proliferation, and apoptosis.

AIM

To evaluate the expression of p53, Ki67 (MIB), bcl2, and bax in oral submucous fibrosis and oral squamous cell carcinoma.

MATERIALS AND METHODS

To assess the immunohistochemical expression of p53, Ki67 (MIB), bcl2, and bax in 50 cases of oral submucous fibrosis (OSF) and ten each of normal and oral squamous cell carcinoma (OSCC).

RESULTS

The labeling indices (LI) of OSF and OSCC were comparable for p53 and Ki67.The p53 LI ranged from 7.9 to 71.9 in OSF and 65.2 to 85.9 in OSCC, and for Ki67 it ranged from 4.39 to 43.23, 18.35 to 42.33, respectively.

CONCLUSION

The p53, Ki67, and bax profiles of OSF and OSCC were altered compared to the normal and these markers could be used as surrogate markers of malignant transformation in OSF.

Clinicopathological features and immunohistochemical expression of p53, Ki-67, Mcm-2 and Mcm-5 in proliferative verrucous leukoplakia

BACKGROUND

Proliferative verrucous leukoplakia (PVL) is a distinct and aggressive type of oral leukoplakia which affects elderly women without risk behavior and presents high rates of malignant transformation. The objective of the present study was to evaluate the clinicopathological characteristics and the distribution of cell proliferation markers, aiming to elucidate the distinct biological behavior of the PVL.

METHODS

Clinical and microscopical features of 12 patients with PVL were reviewed. Immunohistochemical analysis for p53, Ki-67, Mcm-2 and Mcm-5 were performed and the data were correlated.

RESULTS

All patients were women, above 50 years of age, 91.7% were non-smoker and 100% were non-habitual drinker. Alveolar ridge (66.6%), tongue (50%) and buccal mucosa (41.6%) were the most affected sites. Four patients developed squamous cell carcinoma (SCC). The immunohistochemical findings showed higher positivity for p53, Ki-67, Mcm-2 and Mcm-5 in SCCs. However, some patients with mild or moderate dysplasia, specially the patients who developed SCC, presented high expression of Mcm-2 and Mcm-5.

CONCLUSIONS

High immunoexpression of Mcm-2 and Mcm-5 in mild and moderate dysplasia could be helpful to predict the malignant transformation of PVL.

Proliferative verrucous leukoplakia: a concise update

Proliferative verrucous leukoplakia (PVL) is of uncertain etiology but may be associated with human papillomavirus (HPV) infection. Proliferative verrucous leukoplakia is seen mainly in older women, beginning as a simple slow-growing, persistent leukoplakia that tends to spread and become multifocal and affect the gingival frequently. In time, PVL develops exophytic, wart-like or erythroplakic areas that become squamous carcinomas. Proliferative verrucous leukoplakia appears to resist to all attempts at therapy and often recurs.

Frequent alterations of p16INK4a and p14ARF in oral proliferative verrucous leukoplakia

Proliferative verrucous leukoplakia (PVL) represents a rare but highly aggressive form of oral leukoplakia with > 70% progressing to malignancy. Yet, PVL remains biologically and genetically poorly understood. This study evaluated the cell cycle regulatory genes, p16INK4a and p14ARF, for homozygous deletion, loss of heterozygosity, and mutation events in 20 PVL cases. Deletion of exon 1beta, 1alpha, or 2 was detected in 40%, 35%, and 0% of patients, respectively. Deletions of exons 1alpha and 1beta markedly exceed levels reported in non-PVL dysplasias and approximate or exceed levels reported in oral squamous cell carcinomas. Allelic imbalance was assessed for markers reported to be highly polymorphic in squamous cell carcinomas and in oral dysplasias. Loss of heterozygosity was detected in 35.3%, 26.3%, and 45.5% of PVLs for the markers IFNalpha, D9S1748, and D9S171, respectively. INK4a and ARF sequence alterations were detected in 20% and 10% of PVL lesions, accordingly. These data show, for the first time, that both p16INK4a and p14ARF aberrations are common in oral verrucous leukoplakia; however, the mode and incidence of inactivation events differ considerably from those reported in non-PVL oral premalignancy. Specifically, concomitant loss of p16INK4a and p14ARF occurred in 45% of PVL patients greatly exceeding loss reported in non-PVL dysplastic oral epithelium (15%). In addition, p14ARF exon 1beta deletions were highly elevated in PVLs compared with non-PVL dysplasias. These data illustrate that molecular alterations, even within a specific genetic region, are associated with distinct histologic types of oral premalignancy, which may affect disease progression, treatment strategies, and ultimately patient prognosis.

Proliferative verrucous leukoplakia and its progression to oral carcinoma: a review of the literature

BACKGROUND

Proliferative verrucous leukoplakia (PVL) is a distinct clinical form of oral leukoplakia defined by its progressive clinical course, changing clinical and histopathological features, and potential to develop into cancer. PVL behaves in a more aggressive and relentless manner than the more innocuous white oral lesions that it can resemble clinically.

METHODS

A PubMed search was conducted which identified studies that examined patients with PVL and reported data meeting inclusion criteria.

RESULTS

PVL is seen much more frequently in females and most often diagnosed after the sixth decade of life. Tobacco use is not strongly linked to the presence of PVL (63% of patients did not use tobacco products). Most (74%) of the patients with PVL progressed to oral carcinoma.

CONCLUSION

PVL is a persistent and progressive oral lesion that requires very close follow-up along with early and aggressive treatment to increase the chances of a favorable outcome.

Lack of association between proliferative verrucous leukoplakia and human papillomavirus infection

PURPOSE

To analyze proliferative verrucous leukoplakia (PVL) for the presence of human papillomavirus (HPV) in different stages of the disease.

MATERIALS AND METHODS

We studied 13 patients with PVL. In 10 patients (76.9%), a lesional biopsy was taken and frozen at -40 degrees C. Four patients were instructed to mouth rinse with sterile sera. The biopsy and rinse samples were analyzed for HPV by PCR.

RESULTS

We did not detect HPV infection in the PVL tissue or in the oral rinse of any of the 13 patients in any stage of the disease analyzed, neither in oral squamous cell carcinoma nor in the simple hyperkeratosis.

CONCLUSION

There was no association between PVL and HPV infection in our patients.

Human papilloma virus in oral squamous cell carcinoma in a Mexican population

OBJECTIVE

To determine the human papilloma virus (HPV) infection in oral cancer and its association with smoking and drinking habits.

STUDY DESIGN

A cross-sectional study was performed; samples were collected from 51 patients with histological diagnosis of squamous-cell carcinoma were collected at the Instituto Nacional de Cancerología in Mexico City. HPV infection was detected by polymerase chain reaction, and the clinical characteristics of this population were analyzed.

RESULTS

Fifty samples out of 51 were positive for beta-globin; 21 (42%) cases were HPV-positive, and 14/21 were positive for HPV-16. We found more samples positive in men than in women (71% vs 29%). No differences were observed between HPV-positive and -negative patients in relation to smoking and drinking habits (81% vs 79%).

CONCLUSIONS

HPV infection was present in 42% of patients with oral squamous-cell carcinoma (OSCC); HPV-16 was the most frequent type, identified in 66.6%. Other cofactors participate in the development of OSCC, independent of HPV infection.

Proliferative verrucous vs conventional leukoplakia: no significantly increased risk of HPV infection

Proliferative verrucous leukoplakia (PVL) is a very aggressive form of oral leukoplakia (OL) with high morbidity and mortality rates, hypothesised to be linked to HPV infection. This study aimed to determine the presence of HPV DNA in PVL in comparison with OL, and in relation to social-demographical variables (age, gender, smoking and drinking habits) in an Italian multi-centric hospital-based study. The study group consisted of 58 cases of PVL and 90 cases of OL as controls (47 homogeneous (H) and 43 non-homogeneous (non-H) form), both recruited from four Italian cohorts. HPV DNA was identified in exfoliated mucosal cells by nested PCR (nPCR) with MY09/MY11 and GP5+/GP6+ primer pairs and the HPV genotype determined by direct DNA sequencing. HPV DNA was found in 24.1% (14/58)of PVL and in 25.5% (23/90) of OL; there was thus no significant difference found between PVL and OL (both forms) for risk of HPV infection (OR=0.93; 95% IC:0.432-1.985). Similarly, in both groups of PVL and OL lesions, no statistic association was found between any demographical variable considered and HPV infection. HPV-18 was the most frequently detected genotype in all tissues, being found in 78.5% and 60.8% of HPV+ve PVL and OL, respectively. Other more rarely detected genotypes were HPV-16 (28.6% in PVL and 13% in OL), HPV-6 (17.4% in OL) and HPV-53 (8.8% in OL). PVL does not appear more likely to be associated to HPV infection than conventional OL lesions.

Proliferative verrucous leukoplakia: unusual locations of oral squamous cell carcinomas, and field cancerization as shown by the appearance of multiple OSCCs

Proliferative verrucous leukoplakia (PVL) is an uncommon entity with a high tendency to develop oral squamous cell carcinomas (OSCCs). The objective of this study was to analyse the presence of various OSCCs in the same patient with PVL. We studied 19 patients with PVL who had developed at least one OSCC. We analysed how many of these developed more than one OSCC over a period between 24 and a maximum of 130 months, indicating the location of their OSCC, clinical type and the time lapse between the appearance of each of the different OSCCs in the same patient. Of the 19 patients, 10 presented more than one of these cancers, one of whom even went on to develop five different cancers. The most frequent location of OSCC was the gingiva and the palate; the least common was the tongue/floor of mouth. Ninety percent were women and 20% were smokers. The average time elapsed between the detection of the first tumour and the appearance of the second was 19.20 months (SD 13.41). Our patients with PVL developed a high frequency of OSCCs, on many occasions manifesting several cancers at different oral locations, thus demonstrating the field cancerization of this entity. The OSCC in PVL patients were at sites quite uncommonly affected in patients who develop OSCC in the absence of PVL.

Proliferative verrucous leukoplakia: high incidence of gingival squamous cell carcinoma

BACKGROUND

Proliferative verrucous leukoplakia (PVL) is a multifocal and progressive lesion of the oral mucosa, often associated with papillomavirus, seen mainly in older females, and characterized by a high recurrence rate and high rate of transformation into verrucous or oral squamous cell carcinoma (OSCC). The aim of this study was to analyse the clinical characteristics of a substantial group of patients with PVL, evaluating the characteristics of those who developed cancer, and comparing them with a group of patients with OSCC but no preceding PVL.

METHODS

A group of 30 patients with PVL was studied for the clinical aspects and characteristics, age, sex, location, recurrence, the appearance of new lesions, and the frequency of development of oral cancer. A disease control group was formed with 110 patients with OSCC chosen randomly from among those treated in the same Service in this period of time. The patients were grouped as PVL and no cancer (Group 1); PVL developing cancer (Group 2) and patients with OSCC without clinical lesions associated with PVL (Group 3).

RESULTS

The average age of the PVL patients (Groups 1 and 2 combined) was 70.97 +/- 12.73 years, of which 80% were women. Only 23.3% were cigarette smokers. The area most frequently affected with PVL was the lower gingiva. Recurrence after treatment was seen in 86.7%, and new lesions appeared in 83.3%. Many (63.3%) developed cancer (Group 2). Comparison of Groups 2 and 3 patients showed that those with PVL developing cancer were more likely to develop gingival carcinoma and also to be older, more often females, and less likely to smoke tobacco.

CONCLUSION

Cancer developing in patients with PVL manifested particularly on the gingiva.

Aggressive, multifocal oral verrucous leukoplakia: proliferative verrucous leukoplakia or not?

BACKGROUND

Some oral verrucal lesions may constitute parts of the clinicopathological spectrum of proliferative verrucous leukoplakia (PVL). Because of its idiopathic yet sinister nature, it is possible that PVL may exist in other populations. The aim of this study was to review the clinicopathological features of persistent, multifocal, oral verrucal lesions in Malaysian population.

METHODS

Patients with multifocal oral verrucal lesions were selected from surgical and histopathological records.

RESULTS

Nine patients of diverse ethnicity with 43 biopsies were reviewed. The mean age at the presentation was 62 years. The most frequent sites affected were gum, sulci, cheek and tongue. Indulgence in risk habits was reported in about 70% of patients. Four cases developed multifocal carcinoma from multifocal leukoplakia.

CONCLUSIONS

In retrospect, none of the cases fulfilled the original PVL criteria, although three cases were suggestive of PVL. Nevertheless, these findings do not necessarily preclude the existence of PVL as a clinicopathological entity in Malaysian population.

[Proliferative verrucous leukoplakia. Report of five cases]

BACKGROUND

Proliferative verrucous leukoplakia (PVL) is a rare variant of oral leukoplakia (OL) with a high tendency for malignant transformation. PVL starts as a flat hyperkeratosis. During the course of the disease verrucous lesions develop. AIM OF THE STUDY, MATERIAL AND METHODS: Due to the scarcity of reports on PVL five cases of PVL are presented. Clinical and histopathological findings in five female patients with PVL were evaluated retrospectively.

RESULTS

The clinical appearance of PVL was characteristic as compared to criteria described in the literature. The average period of observation in these cases was short (1.7 years). There were 3.6 different localizations observed per patient. The buccal mucosa, gingiva, and edentulous alveolar ridge were most often affected. One patient had already developed squamous cell carcinoma prior to referral. The others developed malignancies during follow-up. Recurrences and secondary malignancies could not be avoided using different therapeutic modalities. Two patients died from PVL. The characteristic spectrum of histopathological findings in PVL was observed. Homogeneous flat leukoplakias are characterized by acanthosis, hyperkeratosis, and often parakeratosis. Epithelial dysplasia is not seen. The proliferative verrucous stage of the disease is characterized by papillomatous epithelial growths with signs of slight epithelial dysplasia and subepithelial infiltration with immunocompetent cells. Stages of transformation may result in verrucous carcinoma or squamous cell carcinoma.

CONCLUSIONS

PVL is associated with a very high rate of malignant transformations. These, as well as recurrences, cannot be avoided with present-day therapies. In order to define the biological profile of PVL more clearly, multicenter studies are necessary to reveal possible etiologic factors and concepts for therapy.

Human papillomavirus as a risk factor for oral squamous cell carcinoma: a meta-analysis, 1982-1997

OBJECTIVE

Human papillomavirus (HPV) infection is a significant risk factor for uterine cervical carcinoma. However, the role of HPV infection in oral squamous cell carcinoma (OSCC) is less well defined. To determine the significance of the relationship of this virus in the progressive development of oral cancer, we estimated the risk of HPV detection in normal oral mucosa, precancerous oral tissue, and oral carcinoma using meta-analysis.

STUDY DESIGN

Case reports and clinical series published in English-language journals were retrieved by searching MEDLINE (January 1980-August 1998). Review articles were also examined to identify additional studies. Studies that used biochemical, immunologic, microscopic, or molecular analyses to detect HPV in tissue or cells derived from normal oral mucosa (n = 25), benign leukoplakia (n = 21), intraepithelial neoplasia (ie, dysplasia and carcinoma in situ; n = 27), and oral cancer (n = 94) were included in the meta-analysis. Information on sample size, age, sex, method of tissue preservation (ie, fresh, frozen, paraffin-embedded), assay, primer amplification region (early, late), high-risk versus low-risk genotype, and use of tobacco or alcohol was abstracted by one author (C.S.M.).

RESULTS

Data from 94 reports that analyzed 4680 samples were included in the meta-analysis. Analyses made by means of a random-effects model with and without adjustments for assay sensitivity showed increased probability of HPV detection in tissue with precancerous and cancerous features compared with normal mucosa. The likelihood of detecting HPV in normal oral mucosa (10.0%; 95% confidence interval [CI], 6.1%-14.6%) was significantly less than of detecting benign leukoplakia (22.2%; 95% CI, 15.7%-29.9%), intraepithelial neoplasia (26.2%; 95% CI, 19.6%-33.6%), verrucous carcinoma (29.5%; 95% CI, 23%-36.8%), and OSCC (46.5%; 95% CI, 37.6%-55.5%). Adjustment of findings for differences in assay sensitivity indicated that these estimates may be conservative. Overall, HPV was between 2 and 3 times more likely to be detected in precancerous oral mucosa and 4.7 times more likely to be detected in oral carcinoma than in normal mucosa. The pooled odds ratio for the subset of studies directly comparing the prevalence of HPV in normal mucosa and OSCC was 5.37, confirming the trend observed in the overall sample. The probability of detecting high-risk HPVs in OSCCs was 2.8 times greater than that of low-risk HPVs.

CONCLUSION

This meta-analysis indicates that HPV is detected with increased frequency in oral dysplastic and carcinomatous epithelium in comparison with normal oral mucosa. The findings provide further quantitative evidence that oral infection with HPV, particularly with high-risk genotypes, is a significant independent risk factor for OSCC.

Expression of p53 tumor suppressor gene in adenoid cystic and mucoepidermoid carcinomas of the salivary glands

Seventeen adenoid cystic carcinomas (ACCs) and 27 mucoepidermoid carcinomas (MECs) occurring in the salivary glands were analyzed for p53 tumor suppressor gene alteration (exons 5-8) and protein expression. The cell proliferation activity was also examined by Ki-67 immunohistochemistry. The p53 alterations were detected in three samples (17.6%) of ACC and in four samples (14.8%) of MEC, and were only found in carcinomas arising in the minor salivary glands. The occurrence of the p53 gene alteration is less frequent in ACC and MEC than that in other kinds of tumors, and therefore does not seem to play a critical role in the course of the tumorigenesis in ACC and MEC. All ACC samples arising from the minor salivary glands exhibiting p53 gene alterations showed recurrence/metastasis, thus suggesting a poor outcome of these patients. All ACCs and three out of four MECs samples with p53 gene alterations showed the lowest degree of p53 immunostaining ratio, thus suggesting that no correlation exists between the p53 gene alterations and the p53 immunostaining in these salivary gland carcinomas. No significant relationship was demonstrated between the immunostaining ratio of either p53 or Ki-67 and the morphological growth pattern or patient clinical course in the ACC samples. The p53 immunopositivity in MEC correlated to the histological grade. The Ki-67 immunostaining ratio was also significantly related to the histological grade and the clinical course in MEC.

A high frequency of allelic loss in oral verrucous lesions may explain malignant risk

Verrucous carcinoma (VC), a variant of squamous cell carcinoma (SCC), is distinct from SCC in morphology and behavior. The underlying genetic changes involved in the development of VC and its precursor verrucous hyperplasia (VH) are unknown. This study determined whether chromosomal regions frequently lost during the development of SCC are also lost in the VH/VC variant. Twenty-five VH and 17 VC were analyzed for loss of heterozygosity (LOH) at 19 loci on 7 chromosome arms using microsatellite analysis. These data were compared with those from 47 reactive hyperplasias, 92 dysplasias (54 low- and 38 high-grade), and 41 SCCS: The results showed that VC/VH shared many of the losses present in dysplasia/SCC but differed in two aspects. First, VC/VH showed early acquisition of loss, compared with a gradual accumulation of losses from dysplasias to SCC. The LOH pattern of VH was similar to that of high-grade dysplasia and sharply different from reactive hyperplasia. The loss in VH often involved multiple arms (in 60% of VH vs 0% of reactive lesions). Only a marginal elevation of loss was observed at 9p (p = 0.06) and 4q (p = 0.05) from VH to VC because of the high degree of loss already present in VH. Second, a strikingly lower frequency of loss at 17p was noted in VH/VC compared with dysplasia/SCC and may indicate human papillomavirus (HPV) involvement. The finding of high-risk LOH profiles in VH may partly account for the high-progression risk seen for VH and also has potentially important clinical implications. The difficult pathological diagnosis of VH/VC from reactive hyperplasia frequently requires repeated biopsies and results in delay in diagnosis and significantly increased mortality/morbidity. Microsatellite analysis might facilitate this differential diagnosis.

Proliferative verrucous leukoplakia of the gingiva

OBJECTIVE

The purpose of this study was to describe the clinical-pathologic features of what appears to be a gingival form of proliferative verrucous leukoplakia.

STUDY DESIGN

Ten adult patients with recurrent and histologically progressive gingival leukoplakias who were diagnosed and treated at the University of California, San Francisco between 1994 and 1999, comprised the subject group for this investigation. Clinical and microscopic features were reviewed. Proliferation indices and p53 expression were evaluated immunohistochemically, and the presence of human papillomavirus (HPV) DNA was determined by using polymerase chain reaction (PCR) amplification.

RESULTS

Lesions presented as solitary or regional flat/papillary/verrucal leukoplakias of the free and attached gingiva (tooth-bearing areas only). With time, flat lesions developed a papillary or verruciform profile. Although lesions were recurrent, they were confined to the gingiva, and multiple lesions did not develop. Half the patients used tobacco, and HPV could not be detected by using PCR. Microscopically, 6 cases began as hyperkeratotic lesions, and 4 initially exhibited a psoriasiform pattern with a marked inflammatory component. With recurrences, the lesions became progressively atypical histologically. The proliferation indices for these lesions showed modest increases over normal epithelium, and positive p53 staining was evident in 4 of 10 cases, indicating a disruption of the keratinocyte cell cycle in these lesions. The mechanism associated with the positive p53 staining (protein binding to wild type p53 versus mutation of the p53 gene) was not determined. Lesions recurred after conservative scalpel or laser excision, and many developed into verrucous or squamous cell carcinoma.

CONCLUSIONS

Proliferative verrucous leukoplakia of the gingiva (PVLG) appears to be a subset of oral proliferative verrucous leukoplakia. It can be characterized as a solitary, recurring, progressive white patch that develops a verruciform architecture and may not be associated with HPV. PVLG has an unpredictable course and is at risk for development into verrucous or squamous cell carcinoma. Currently, there is no way to determine or predict which gingival white lesions will follow the clinical course described for this group of patients with PVLG.

Relation between p53 overexpression and clinical behavior of ocular/orbital invasion of conjunctival squamous cell carcinoma

PURPOSE

To investigate the p53 gene as a prognostic indicator in conjunctival squamous cell carcinoma.

METHODS

Medical records were reviewed and histopathology slides were examined to verify the diagnosis and grade of tumor differentiation in a retrospective case series of 12 patients with "invasive" and 11 patients with "noninvasive" conjunctival squamous cell carcinoma. The p53 antigen was detected using the streptavidin biotin-alkaline phosphatase immunostaining method. Statistical analysis was performed using the Fisher exact test.

RESULTS

p53 overexpression was present in 14 cases (approximately 60%). Eight and 6 of 14 p53-positive tumors were invasive and noninvasive, respectively. All patients with recurrence (two), recurrence and metastasis (two), metastasis (three), and death with tumor dissemination (three) had p53 overexpression. Of all adverse outcomes, only two cases with recurrence were p53 negative: no metastasis or death with dissemination was seen in p53-negative tumor cases.

CONCLUSIONS

There was no statistical relationship between p53 overexpression and age, sex, location, invasiveness, or histopathologic differentiation of the tumor; however, a significant association existed between p53 positivity and adverse clinical behavior (p = 0.014).

Incidence of human papillomavirus 16 and 18 infection and p53 mutation in patients with oral squamous cell carcinoma in Japan

The purpose of this study was to investigate the prevalence of human papillomaviruses (HPVs) 16 and 18 infection, and p53 mutation in oral squamous cell carcinomas (SCCs) in Japanese patients. Our results showed a higher incidence of HPV16 and 18 infections than previous studies because we combined the findings of a consensus polymerase chain reaction (PCR), restriction fragment length polymorphism by using the restriction enzyme digestion of the PCR products and Southern blot hybridization. Each HPV16 and 18 E6/E7 DNA was detected in 9 (20%) and 25 (54%) of 46 samples. The p53 mutation in the exons from 5 to 8 were detected in 20 out of 46 samples (43%) by a PCR-single strand conformation polymorphism analysis. There was a significant relationship between HPV16 and the p53 mutation (P =0.02) suggesting that HPV16 infection has a mutagenic effect in oral SCC. However, neither HPV infection nor p53 mutation influenced survival.