Oral Epithelial Lesions Research Articles

Design and characterization of a handheld multimodal imaging device for the assessment of oral epithelial lesions.

A compact handpiece combining high resolution fluorescence (HRF) imaging with optical coherence tomography (OCT) was developed to provide real-time assessment of oral lesions. This multimodal imaging device simultaneously captures coregistered en face images with subcellular detail alongside cross-sectional images of tissue microstructure. The HRF imaging acquires a 712 × 594 μm² field-of-view at the sample with a spatial resolution of 3.5 μm. The OCT images were acquired to a depth of 1.5 mm with axial and lateral resolutions of 9.3 and 8.0 μm, respectively. HRF and OCT images are simultaneously displayed at 25 fps. The handheld device was used to image a healthy volunteer, demonstrating the potential for in vivo assessment of the epithelial surface for dysplastic and neoplastic changes at the cellular level, while simultaneously evaluating submucosal involvement. We anticipate potential applications in real-time assessment of oral lesions for improved surveillance and surgical guidance.

Evaluation of hTERC (3q26) gain by fluorescence in situ hybridization (FISH) to predict the behavior of oral epithelial precursor lesions

Oral Squamous Cell Carcinoma (OSCC) is the most common tumor of the oral cavity. Approximately 500.000 new cases of OSCC are diagnosed worldwide each year with the incidence seemingly increasing. Chemo- and radiotherapy are potential curative procedures although destructive surgery is often necessary if early diagnosis is not achieved. Such procedures impact heavily on human and social costs. Infection of oral mucosa by oncogenic HPV is strongly associated with OSCC among subjects with established risk factors such as tobacco and alcohol abuse. The development of OSCC is a multistep process in which accumulated genetic and epigenetic events lead to cell cycle deregulation and chromosomal abnormalities. Gain of chromosome 3 (which contains human telomerase RNA gene, hTERC, located on chromosome 3q26) appears to be an important selective advantage in the progression of cervical intraepithelial neoplasia to invasive cancer [1] as well as in the progression to invasive head and neck carcinoma [2]. We utilized automated interphase FISH to evaluate the gain of chromosome 3 (3q26) and 7 (CEP) in oral epithelial precursor lesions in order to determine whether aneuploidy is already present and thus whether it is possible to anticipate diagnosis and clinical interventions. Retrospective in blind analysis on 40 oral samples with long-term follow up (ranging from 5 to 10 years) and with initial histological diagnosis of mild and moderate dysplasia, will be run. Preliminary results (8 samples) showed that tumor cells were already present only in the cases that progressed to cancer (4/8) [figure ​[figure1];1]; these preliminary findings confirm the usefulness of FISH as a reflex test in case of morphologically assessed pre-cancerous lesions, and highlight the potential value of this technique for early diagnosis and thus earlier treatment with less destructive therapeutic approaches. Figure 1

Photodynamic Therapy for Actinic Cheilitis: A Option for Treatment

Photodynamic therapy (PDT) is widely used in dermatological diseases and is currently indicated for the treatment of oral epithelial precursor lesions such as actinic cheilitis (AC). Study Design: This study assessed the efficacy of two sessions of PDT using 5-aminolevulinic acid methyl ester cream and a red LED light source in 15 patients with AC. Results: Histopathological analysis after PDT demonstrated that in four patients with mild epithelial dysplasia (ED), one patient changed to no ED, one patient maintained the ED, and two patients changed to moderate ED. In seven patients with moderate ED, one patient had total remission of ED, three patients reduced the ED, and three patients remained with ED. In four patients with severe DE, two patients showed no ED and two patients changed to mild ED. Conclusion: PDT might be an alternative for the treatment of AC, but the literature still lacks research regarding clinical trials and protocols.

Cortactin and focal adhesion kinase as predictors of cancer risk in patients with premalignant oral epithelial lesions

There is a need for novel and accurate biomarkers based on genetic abnormalities capable of predicting the risk of malignant transformation of epithelial lesions of the oral cavity. Therefore, we investigate the role of cortactin and focal adhesion kinase (FAK) protein expression in oral dysplasias and their potential utility as cancer risk markers. Cortactin and FAK expression were immunohistochemically evaluated in 64 patients with oral epithelial dysplasia. During follow-up, 17 of 64 patients developed an oral squamous cell carcinoma (OSCC). Increased immunoexpression of cortactin and FAK was found in 52 and 27 of 64 oral dysplasias, respectively, and the expression of both proteins increased with the grade of dysplasia. Increased cortactin and FAK expression was also observed in 13 and 15 OSCC, respectively. Overall, cortactin and FAK expression was maintained or further augmented in the oral squamous cell carcinoma compared to the patient-matched preinvasive lesion. Univariate analysis showed that cortactin and FAK expression, as well as histological grading were significantly associated with oral cancer risk. Strong coexpression of both proteins reflected a significantly higher cancer risk than that of weak to moderate expression or than whenever only one of those proteins showed a strong expression. In multivariate analysis, premalignant oral lesions which exhibited a high coexpression of cortactin and FAK showed a significant risk of developing an OSCC (HR=6.298). Our results indicate that strong immunoexpression of cortactin and FAK, and not only one of them, is a predicting factor for increased cancer risk in oral premalignant lesions.

Expression of epithelial growth factor receptor in oral epithelial dysplastic lesions

Aim:The aim of the study was to assess the expression of epithelial growth factor receptor (EGFR) in normal oral mucosa and varying grades of oral epithelial dysplasia (OED) and to correlate these findings, with clinicopathologic features and findings on routine hematoxylin and eosin–stained (H and E) sections.Materials and Methods:Twenty-nine formalin-fixed, paraffin-embedded blocks of various grades of OED and 10 normal mucosa were stained with routine H and E and immunostained with EGFR by avidin–biotin method.Results:The results showed a significant increase in the staining reactions in varying grades of dysplasia as compared with normal mucosa.Conclusion:EGFR can be considered as an early marker of a cell proliferation and maturation as well as early marker of epithelial dysplasia and onset of cancer in oral dysplasia. However, further studies with a larger sample size and continuous followup is suggested to determine its role and significance precisely.

Enhanced Expression of Podoplanin in Oral Carcinomas in situ and Squamous Cell Carcinomas

Objective: Podoplanin, a known lymphatic endothelial cell marker, has been reported to be expressed in various types of cancer. To elucidate the expression of podoplanin in precancerous lesions, we examined the immunohistochemical profiles of podoplanin in oral squamous epithelial lesions. Method: We studied a total of 298 foci of squamous cell carcinoma (SCC), carcinoma in situ (CIS), epithelial dysplasia, and hyperplastic and/or normal epithelial lesions by immunohistochemistry using D2-40. Results: There was no positivity for podoplanin in normal or hyperplastic epithelia, while all of the CIS and SCC foci stained positive. Approximately one third of the mild dysplasia foci (10 of 36 foci, 28%) and 80% of moderate dysplasia foci (78/98) showed grade 1 positive reactions (positive only in the 1st layer). Grade 2 reactions (up to 4th layer) were seen in 4 of 98 moderate dysplasia foci (4%), 29 of 74 CIS foci (39%), and 3 of 30 SCC foci (10%). Grade 3 reactions (to more than 5th layer) were found in 35 (47%) CIS foci and 26 (87%) SCC foci. Conclusions: The relationship between the present histological categorization and podoplanin grade was statistically significant. D2-40 expression is considered to be related to the severity of oral precancerous lesions.

Emergence of keratin 17 vs. loss of keratin 13: Their reciprocal immunohistochemical profiles in oral carcinoma in situ

To evaluate differential expressions for keratin (K) subtypes 13 and 17 in oral borderline malignancies, we examined 67 surgical specimens of the oral mucosa for their immunohistochemical profiles. From those specimens, 173 foci of epithelial dysplasia, 152 foci of carcinoma in situ (CIS), and 82 foci of squamous cell carcinoma (SCC) were selected according to our diagnostic criteria, along with 20 areas of normal epithelia. In normal epithelia, there was no K17 positivity (0%), whereas definite K13 positivity (100%) was observed. The same tendencies were obtained in mild (undefined) and moderate (true) epithelial dysplasias (K17: 0%; K13: 100%). In contrast, all CIS (100%) had K17 positivities, while K13 positivities were lost in many of them (7%). Similar tendencies were confirmed in invasive SCC (K17: 100%, K13: 4%). Simultaneous immunopositivities for K17 and K13 were found only in SCC (7%) and CIS (4%) foci with distinct keratinization. These foci also showed K10 positivities, though K10 positive areas were not identical to K13 positive areas. The results indicate that expressions of K17 and K13 are reciprocal in oral epithelial lesions and that the K17 emergence is related to malignancies.

口腔前癌病変, 早期がんの病理

There is no absolute proof of which morphological type of non-invasive cancer develops to advanced cancer. Traditionally, WHO epithelial dysplasia has been used to pathologically diagnose oral epithelial precursor lesions. In 2005, squamous intraepithelial neoplasia （SIN1-3） were classified parallel to Head and neck tumours classification of WHO. In the classification, each corresponds to the following: Mild dysplasia to SIN1, moderate dysplasia to SIN2, severe dysplasia and carcinoma in-situ to SIN3. Oral cavity was discussed as epithelial precursor lesions, early intraepithelial tumor which differentiation is only seen in the surface area, as well as hypopharynx, larynx, trachea, and oropharyngeal. In our country, this intraepithelial neoplasia was histopathologically known to some pathologist from the early stage. Mostly this was clinically treated as malignant tumor although there is no unified rule countrywide at the moment. In 2010, oral intraepithelialneoplasia （OIN）/ carcinoma in-situ （CIS） was enrolled to Japan society for oral tumors as histological classification. Because there are so many classifications that are discussed currently, people are confused of clinical correspondence, interpretation of each and which ones to use.

Immunohistochemical expression of p16INK4A protein as a helpful marker of a subset of potentially malignant oral epithelial lesions: study on a series with long‐term follow‐up

To examine a group of lesions that progressed to oral squamous cell carcinoma (OSCC) to determine whether p16(INK4A) expression is an early finding during malignant transformation, and whether immunohistochemical evaluation of p16(INK4A) is an appropriate prognostic marker. Twenty cases of OSCC were investigated. All cases had had a biopsy on the same site as OSCC performed at least 1year before OSCC (range 1-11years; mean 3.15±3.1years). Twenty specimens from normal oral mucosa served as controls. p16(INK4A) expression was evaluated by immunohistochemical analysis and cases showing >5% of stained cells were defined as 'positive'. All 20 control cases were negative for p16(INK4A) . Oral lesions were p16(INK4A) -positive in nine cases and negative in 11. No significant relationship was found between p16(INK4A) positivity and the presence/absence of dysplasia. Among OSCC, nine tumours showed p16(INK4A) positivity and 11 showed negativity. A significant relationship (χ(2)=7.1; P<0.01) was found between the presence/absence of p16(INK4A) staining in OSCC and the presence/absence of p16(INK4A) staining in lesions preceding OSCC. p16(INK4A) immunohistochemistry has a potential role in detecting a subset of p16(INK4A) -positive lesions with malignant potential.

Histopathological evaluation including cytokeratin 13 and Ki-67 in the border between Lugol-stained and -unstained areas

Lugol's iodine staining (Lugol-staining) has been widely used to detect malignant changes in the cervix uteri and esophagus. However, pathological and histochemical changes in the border between Lugol-stained and -unstained areas in oral epithelial dysplastia and malignant lesions are not well understood. We examined the histological appearance of 20 cases of epithelial dysplasia surrounding squamous cell carcinoma using HE and PAS staining in the borders between Lugol-stained and -unstained areas. Subsequently, differences in the expression of cytokeratin 13 (CK13), an epithelium differentiation marker, and Ki-67, a cell proliferative marker, in those areas were investigated by immunohistochemistry. Lugol-stained areas of all cases showed mild dysplasia or normal epithelium appearance, while Lugol-unstained areas in most cases were diagnosed as moderate/severe dysplasia and carcinoma in situ. PAS reactions were limited or not found in the Lugol-unstained areas as compared to intense positivity in Lugol-stained areas. CK13 and Ki-67 protein expression was significantly different between Lugol-stained and -unstained areas. It was confirmed that epithelia showing precancerous or cancerous features were detected as Lugol-unstained boundary areas. A reduction in glycogen production caused by alterations of cell differentiation and proliferation associated with malignant changes may result in a lack of Lugol-staining.

Glycogen synthase kinase 3 beta: can it be a target for oral cancer

Despite progress in treatment approaches for oral cancer, there has been only modest improvement in patient outcomes in the past three decades. The frequent treatment failure is due to the failure to control tumor recurrence and metastasis. These failures suggest that new targets should be identified to reverse oral epithelial dysplastic lesions. Recent developments suggest an active role of glycogen synthase kinase 3 beta (GSK3 β) in various human cancers either as a tumor suppressor or as a tumor promoter. GSK3β is a Ser/Thr protein kinase, and there is emerging evidence that it is a tumor suppressor in oral cancer. The evidence suggests a link between key players in oral cancer that control transcription, accelerated cell cycle progression, activation of invasion/metastasis and anti-apoptosis, and regulation of these factors by GSK3β. Moreover, the major upstream kinases of GSK3β and their oncogenic activation by several etiological agents of oral cancer support this hypothesis. In spite of all this evidence, a detailed analysis of the role of GSK3β in oral cancer and of its therapeutic potential has yet to be conducted by the scientific community. The focus of this review is to discuss the multitude of roles of GSK3β, its possible role in controlling different oncogenic events and how it can be targeted in oral cancer.

Methylation of p16 CpG Island Associated with Malignant Progression of Oral Epithelial Dysplasia: A Prospective Cohort Study

Inactivation of p16 gene by CpG methylation is a frequent event in oral epithelial dysplasia. To investigate the predictive value of p16 methylation on malignant potential in oral epithelial dysplasia, we carried out the prospective cohort study. One hundred one patients with histologically confirmed mild or moderate oral epithelial dysplasia were included in the present cohort study. p16 Methylation status of the oral epithelial dysplasia lesions from 93 cases was obtained by methylation-specific PCR. Progression of the oral epithelial dysplasia lesions was examined in 78 cases histologically during a 45.8 months follow-up period. The association between p16 methylation and progression of oral epithelial dysplasia was analyzed. Of the 93 enrolled cases, 15 cases were lost during the follow-up because of changes of contact information, with a compliance of 83.9%. p16 Methylation was detectable in oral epithelial dysplasia lesions from 32 (41.0%) of 78 enrolled patients. Oral epithelial dysplasia-related squamous cell carcinomas were observed in 22 patients (28.2%) during the follow-up. Rate of progression to oral cancer in patients with the p16-methylated oral epithelial dysplasia was significantly higher than that with the p16-unmethylated oral epithelial dysplasia (43.8% versus 17.4%; adjusted odds ratio, 3.7; P = 0.013), especially for patients at the baseline age of > or = 60 years (adjusted odds ratio, 12.0; P = 0.003) and patients with moderate oral epithelial dysplasia (adjusted odds ratio, 15.6; P = 0.022). The overall sensitivity and specificity of prediction of malignant transformation of oral epithelial dysplasia by p16 methylation were 63.6% and 67.9%, respectively. p16 Methylation was correlated with malignant transformation of oral epithelial dysplasia and is a potential biomarker for prediction of prognosis of mild or moderate oral epithelial dysplasia.

Angiogenic squamous dysplasia-like phenomenon in oral epithelial precursor lesions

Statement of the problemDysplasia, the morphological yardstick of epithelial precursor lesions, is the collective term for a variety of architectural and cytological changes within the altered oral epithelium. Angiogenic squamous dysplasia (ASD), a distinct morphological characteristic in pre-invasive bronchial lesions, describes the presence of capillary tufts that are closely juxtaposed to and projecting into the dysplastic bronchial epithelium.ObjectiveTo determine whether ASD-like phenomenon occurs in oral epithelial precursor lesions, and to speculate on its relevance.MethodsTwenty cases each of mild, moderate and severe oral dysplasia (inclusive of carcinoma-in-situ), and 10 normal oral mucosa (normal controls) were serial sectioned for H and E staining, and for microvessel density (MVD) scoring with CD31, CD34 and CD105. Microcapillary pattern images were digitally captured for 3-D reconstruction.ResultsOral ASD foci consisting of CD31-and CD34-positive capillary loops abutting onto the overlying dysplastic oral epithelium (and causing it to assume an irregular or papillary surface configuration) were identified in moderate (3/20; 15%) and severe dysplasia (13/20; 65%), but not in normal oral mucosa and mild dysplasia. MVD score demonstrated increasing vascularity as epithelium progressed from normal to severe dysplasia (p < 0.05). CD105 demonstrated increase neovascularization in all dysplasia grades (p < 0.05).ConclusionsThese preliminary findings taken together suggest that: 1. ASD-like phenomenon may be an important intermediary biomarker in oral precursor lesions; and 2. architectural alterations of the entire disturbed mucosa may be a more useful pre-malignancy index.

Poster 022: Pharmacokinetic Analyses of Chemopreventive Bioadhesive Berry Gel in Humans

Early diagnosis and management of premalignant oral epithelial lesions is the optimal strategy to decrease oral squamous cell carcinoma (OSCC) morbidity and mortality. Chemoprevention, the prevention, inhibition or reversal of malignant transformation by intervention with chemically derived or naturally occurring dietary substances, is a promising treatment approach.

Expression pattern of p63 in oral epithelial lesions and submucous fibrosis associated with betel-quid chewing in Sri Lanka

Betel-quid chewing, which is closely related to the high incidence of oral cancer, is prevalent in Sri Lanka. p63 has a remarkable structural similarity to p53, suggesting an aberrant expression in oral cancer. Using anti-p63 antibody and immunohistochemistry, the present study investigated the expression pattern of p63 in oral epithelial lesions, including different types of squamous cell carcinoma (SCC), different grades of epithelial dysplasia, and submucosal fibrosis associated with betel-quid chewing. Nuclear immunoreactivity for p63 was detected in all the cases, including normal oral epithelium and epithelial lesions. In normal oral epithelium, nuclear positivity for p63 was observed in some of the basal cell layers and focally in the parabasal layer. Nuclear positivity increased in the epithelial lesions. The percentage of positive nuclei in the epithelial lesions was significantly higher than in normal epithelium (P < 0.01) and was also significantly higher in oral submucosal fibrosis than in epithelial dysplasia (P < 0.05). The results indicate that the overexpression of p63 in oral precancerous lesions and SCC in betel-quid chewers in Sri Lanka may be a useful marker for oral precancerous lesions.

Malignant transformation in 1458 patients with potentially malignant oral mucosal disorders: a follow‐up study based in a Taiwanese hospital

It is generally accepted that the development of cancer in the oral mucosa is preceded by an identifiable non-invasive precursor lesion. The aim of this follow-up study was to estimate the rate and the time to transformation in a group of patients from southern Taiwan with potentially malignant oral epithelial lesions. The follow-up time is defined as the duration between the onset of the initial diagnosis and the occurrence of confirmed oral cancer. A total of 1458 patients with histological diagnoses of various pre-malignant oral lesions were followed up between 1991 and 2001. The average age at initial diagnosis was 47.5 years. The histological diagnoses were divided into six categories: epithelial dysplasia with hyperkeratosis/epithelial hyperplasia (8.85%); epithelial dysplasia with submucous fibrosis (2.54%); submucous fibrosis (27.57%); hyperkeratosis/epithelial hyperplasia (29.01%); lichen planus (9.80%) and verrucous hyperplasia (22.22%). Within the cohort of 1458 patients, 44 patients progressed to oral cancer in the same site as the initial lesions with an overall transformation rate of 3.02% and a mean follow-up time of 42.64 months. Eight of the 166 patients with dysplastic lesions and 15 of 423 patients with hyperkeratosis/epithelial hyperplasia progressed to malignancy. The other patients with malignant transformation originated from various pre-cancerous oral lesions and conditions (submucous fibrosis, eight of 402; lichen planus, three of 143; verrucous hyperplasia, 10 of 324). These results indicate that patients with pre-malignant oral lesions need long-term follow up.

Comparative analysis of CD1a, S-100, CD83, and CD11c human dendritic cells in normal, premalignant, and malignant tissues.

A number of antibodies that recognize human dendritic cells (DC) have been identified. The main aim of this study was to compare and contrast different antigen retrieval techniques using both enzymatic and non-enzymatic treatments in order to determine the expression and distribution of several DC markers on formalin-fixed, paraffin-embedded tissues. Normal human lung, oral epithelial hyperplasia lesions, oral squamous cell carcinoma, and prostate adenocarcinoma tissues were evaluated using a panel of DC specific antibodies. The results of immunohistochemical staining for CD83, CD1a, CD11c, and S-100 DC markers were compared following the different antigen retrieval approaches. The overall best results for the analysis of tumor-associated DC were obtained with the enzymatic methods. Protease XXIV digestion was determined to be essential for detection of S-100 and CD11c positive DC, whereas trypsin and pepsin were required for the recognition of CD1a and CD83 expressing tumor-associated DC. These results could be easily adapted for routine practice and should be useful for characterization of the DC system in cancer patients for both diagnostic and prognostic purposes. In addition, standardized procedures for evaluating different subpopulations of tumor-associated DC should bring new insights in understanding of DC-tumor cell interaction.

Frequent allelic imbalances at 8p and 11q22 in oral and oropharyngeal epithelial dysplastic lesions

Allelic imbalance is characteristic of oral squamous cell carcinoma (SCC) and contributes to the tumorigenesis of this disease. Our previous studies suggest that chromosome regions 8p and 11q22.2∼q22.3 are frequent sites of loss of heterozygosity (LOH) in head and neck SCC. Here, we explored the allelic imbalance pattern of these regions in 27 cases of oral epithelial dysplastic lesions. A previously reported frequent LOH (9p21) in head and neck dysplasia was also examined. Laser capture microdissection (LCM) technology was utilized to harvest homogenous cell populations from archived clinical tissues and thus greatly enhancing the sensitivity, accuracy and reliability of genetic assessment. The allelic imbalance (LOH and microsatellite instability) on 8p, 11q22.2∼q22.3, and 9p21 were observed at one or more loci in 66.7%, 63.0%, and 63.0% of cases, respectively. Our results demonstrate that 8p, 11q22.2∼q22.3, and 9p21 are frequent allelic imbalance regions in oral premalignant dysplasia and suggest the presence of tumor suppressor genes in these regions.

Angiogenic Squamous Dysplasia in Oral Epithelial Dysplastic Lesions

Statement of problem: Angiogenic squamous dysplasia (ASD), a qualitative distinct form of angiogenesis, was first described in pre-invasive bronchial mucosa of high-risk individuals. It is characterized histologically by the presence of capillary tufts that are closely juxtaposed to and projecting into the dysplastic bronchial epithelium. Objective: To determine whether ASD occurs in oral epithelial dysplastic lesions. Methods: Sixty cases of potentially malignant oral epithelial lesions comprising 20 mild epithelial dysplasia (ED), 20 moderate ED and 20 severe ED(inclusive of carcinoma-in-situ), and 10 normal oral mucosa (as normal controls) were retrieved from the archives of the Department of Oral Pathology, Oral Medicine & Periodontology, Faculty of Dentistry, University of Malaya, and the Cancer Research Centre, Institute for Medical Research, Kuala Lumpur, Malaysia. The grading of oral ED was in accordance with the recommendations of the World Health Organization. For all selected cases, new 5 micron thick sections were prepared for H&E staining, and for immunohistochemistry with three vascular markers, CD31, CD34 and CD105, with appropriate positive and negative controls. The established criteria for identification of ASD was applied. Results: ASD was identified in parts of severe oral ED, but was absent in normal oral epithelium, mild and moderate oral ED. About 65% of these severe oral ED cases were from individuals with high-risk habits. As with bronchial ASD, the capillaries typically formed CD31- and CD34-positive projections or loops that abut onto the overlying dysplastic oral epithelium causing the latter to assume a papillary surface configuration. Unlike bronchial ASD which occurs in respiratory-type epithelium, oral ASD was found in keratinzed stratified squamous epithelium. CD105 confirmed the presence of neoangiogenesis. Conclusions: Present findings confirm that ASD can occur in oral severe ED. It also demonstrates that this angiogenic abnormality is not unique to bronchial mucosal dysplastic lesions.

Assessment of c-Jun, c-Fos and cyclin D1 in premalignant and malignant oral lesions

Some oral cancers are known to develop from dysplastic oral epithelium. In the present study, the expression of c-Jun, c-Fos, and cyclin D1 proteins in oral epithelial lesions with different degrees of dysplasia, and in oral squamous cell carcinomas (OSCCs) was evaluated. Eighteen cases of mild dysplasia, 23 cases of moderate to severe dysplasia and 24 OSCCs were studied immunohistochemically. Additionally, 15 sections of oral mucosa without any evidence of dysplasia were included in the study. c-Jun expression increased according to the degree of oral dysplasia, with the greatest expression found in OSCC. c-Fos expression was intense in normal mucosa, reduced in mild dysplasia and high in moderate to severe dysplasia and in OSCCs. Cyclin D1 was expressed in only a few cases of moderate to severe dysplasia and in most of the OSCCs. Statistical analysis showed a correlation between the three proteins and the degree of epithelial alteration. The present results indicate a possible role of c-Jun and c-Fos in malignant transformation of oral mucosa.