Expression of p63 protein and mRNA in oral epithelial dysplasia

Prediction of Lymphovascular and Perineural Invasion of Oral Squamous Cell Carcinoma by Combined Expression of p63 and Cyclin D1

OBJECTIVES

 The aim of this study was to determine the value of immune expression of p63 and cyclin D1 in the prediction of lymphovascular invasion (LVI) and perineural invasion (PNI) in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

 Clinical and histopathologic features of 65 subjects with histologically confirmed OSCC were collected. Tissue microarray blocks representing all subjects were prepared for the immunohistochemical quantification of the nuclear expression of p63 and cyclin D1 using immune ratio plugin of image J software. Image analysis was performed by two independent pathologists. Independent samples t-test, analysis of variance, and receiver operating characteristic curve tests were used for statistical analysis. The level of significance was set at p≤ 0.05.

RESULTS

 The optimum cutoff value for the prediction of LVI for p63 and cyclin D1 was found to be 100 and 93.2, respectively, while the optimum cutoff value for the prediction of PNI for p63 and cyclin D1 was found to be 95.9 and 94, respectively. p63 and cyclin D1 expression correlated with several clinicopathologic features of the studied population. p63 expression was a significant predictor of moderate/poorly differentiated OSCC compared with well-differentiated OSCC. A parallel combination of positive p63 and cyclin D1 increased the specificity of predicting LVI from 89.1% and 67.4% for either p63 or cyclin D1, respectively, to 93.5% with a positive predictive value of 92.5%. Similarly, the parallel combination of the two markers raised the specificity of predicting PNI from 70% and 77.5% for either p63 or cyclin D1, respectively, to 90% with a positive predictive value of 86.3%.

CONCLUSION

 Combined overexpression of nuclear markers p63 and cyclin D1 can be considered as a valuable independent predictor of LVI and PNI, and hence tumor progression, in OSCC.

Expression of p53, p63, podoplanin and Ki-67 in recurring versus non-recurring oral leukoplakia

Oral leukoplakia (OL), a potentially malignant disorder, recurs in 40% of cases after surgical removal. Recurrence is a risk factor for malignant transformation. We aimed to examine the prognostic significance of four biomarkers related to cell proliferation: p53, p63, podoplanin (PDPN) and Ki-67 in predicting recurrence. Formalin-fixed-paraffin-embedded specimens from excised OL (n = 73, 33 recurrent; 40 non-recurrent) were collected in a prospective study. Immunohistochemistry was used to visualise expression of p53, p63, PDPN and Ki-67. Image analysis software was used for quantification of p53-, p63- and Ki-67-expressing cells, while PDPN was analysed visually. The expression of all four proteins were higher in recurrent compared with non-recurrent OL, only expression of p53 was statistically significant. In uni- and multivariable Cox regression analyses of individual markers, expression of p63 was significantly associated with higher recurrence risk (p = 0.047). OL with a combined high expression of both p53 and p63 had a significantly higher risk to recur [Log Rank, p = 0.036; multivariate Cox, HR: 2.48 (1.13–5.44; p = 0.024)]. Combination of p53 and p63 expression may be used as a prognostic biomarker for recurrence of OL.

Collagen deposition correlates with loss of E-cadherin and increased p63 expression in dysplastic conditions of oral submucous fibrosis

This paper focuses on the status of epithelial markers, E-cadherin, and p63 in the backdrop of an abnormal amount of collagen in the sub-mucosa of dysplastic and non-dysplastic grades of OSF. Histologically confirmed OSF and normal oral mucosa samples were procured. Samples were stained by Van Gieson's stain (VG) and immunohistochemistry. The captured images were analyzed by ImageJ software to quantify their grayscale intensities. There was a gradual increase in the intensity of VG stain from normal to non-dysplastic and dysplastic OSF and the differences in their mean grayscale values were found to be significant (p < 0.00001). The intensity of E-cadherin was found to be the highest in non-dysplastic conditions and lowest in dysplastic conditions. The intensity difference of E-cadherin between normal and non-dysplastic OSF was found to be significant (p < 0.00001). The grayscale scale intensity values for p63 in whole epithelium depicted significant differences between normal and diseased conditions but for its intensity, in basal cells, significant differences were found between non-dysplastic and other classes of tissues. There was a positive correlation observed between VG and p63 staining intensity. The diseased oral epithelium demonstrated greater deposition of sub-epithelial collagen fibers along with subsequent loss of E-cadherin and an increased p63 expression.

Predicting the clinical outcome of oral potentially malignant disorders using transcriptomic-based molecular pathology

BACKGROUND

This study was undertaken to develop and validate a gene expression signature that characterises oral potentially malignant disorders (OPMD) with a high risk of undergoing malignant transformation.

METHODS

Patients with oral epithelial dysplasia at one hospital were selected as the 'training set' (n = 56) whilst those at another hospital were selected for the 'test set' (n = 66). RNA was extracted from formalin-fixed paraffin-embedded (FFPE) diagnostic biopsies and analysed using the NanoString nCounter platform. A targeted panel of 42 genes selected on their association with oral carcinogenesis was used to develop a prognostic gene signature. Following data normalisation, uni- and multivariable analysis, as well as prognostic modelling, were employed to develop and validate the gene signature.

RESULTS

A prognostic classifier composed of 11 genes was developed using the training set. The multivariable prognostic model was used to predict patient risk scores in the test set. The prognostic gene signature was an independent predictor of malignant transformation when assessed in the test set, with the high-risk group showing worse prognosis [Hazard ratio = 12.65, p = 0.0003].

CONCLUSIONS

This study demonstrates proof of principle that RNA extracted from FFPE diagnostic biopsies of OPMD, when analysed on the NanoString nCounter platform, can be used to generate a molecular classifier that stratifies the risk of malignant transformation with promising clinical utility.

EGF-mediated suppression of cell extrusion during mucosal damage attenuates opportunistic fungal invasion

Severe and often fatal opportunistic fungal infections arise frequently following mucosal damage caused by trauma or cytotoxic chemotherapy. Interaction of fungal pathogens with epithelial cells that comprise mucosae is a key early event associated with invasion, and, therefore, enhancing epithelial defense mechanisms may mitigate infection. Here, we establish a model of mold and yeast infection mediated by inducible epithelial cell loss in larval zebrafish. Epithelial cell loss by extrusion promotes exposure of laminin associated with increased fungal attachment, invasion, and larval lethality, whereas fungi defective in adherence or filamentation have reduced virulence. Transcriptional profiling identifies significant upregulation of the epidermal growth factor receptor ligand epigen (EPGN) upon mucosal damage. Treatment with recombinant human EPGN suppresses epithelial cell extrusion, leading to reduced fungal invasion and significantly enhanced survival. These data support the concept of augmenting epithelial restorative capacity to attenuate pathogenic invasion of fungi associated with human disease.

Wurster et al. show that extrusion of numerous epithelial cells from tissue can expose underlying extracellular matrix components to promote increased attachment and invasion of fungi associated with human disease. Treatment with recombinant human EPGN suppressed epithelial cell extrusion, leading to significantly reduced opportunistic fungal invasion.

The inhibition effect of natural food supplement active ingredients on TP63 carcinoma cell

In pancreatic cancer, the activities of inhibitory agents were investigated using docking, since the inhibition of TP63, which plays an important role in the spread of cancer with metastasis, in preventing the proliferation and proliferation of this type of cancer. It has been shown that the active ingredients in some plants used as traditional medicines have an inhibitory effect on this cancer type in preventing growth, reproduction and spread. These computational results guide experimental studies, preventing time and item loss; It is an important study in terms of choosing and using the right active substances.

Immunohistochemical evaluation of p63 and cyclin D1 in oral squamous cell carcinoma and leukoplakia

Objectives

There are only a limited number of studies on cyclin D1 and p63 expression in oral squamous cell carcinoma (OSCC) and leukoplakia. This study compared cyclin D1 and p63 expression in leukoplakia and OSCC to investigate the possible correlation of both markers with grade of dysplasia and histological grade of OSCC.

Materials and Methods

The study included a total of 60 cases, of which 30 were diagnosed with OSCC and 30 with leukoplakia, that were evaluated immunohistochemically for p63 and cyclin D1 expression. Protein expression was correlated based on grades of dysplasia and OSCC.

Results

Out of 30 cases of OSCC, 23 cases (76.7%) were cyclin D1 positive and 30 cases (100%) were p63 positive. Out of 30 cases of leukoplakia, 21 cases (70.0%) were cyclin D1 positive and 30 (100%) were p63 positive (P<0.05).

Conclusion

The overall expression of cyclin D1 and p63 correlated with tumor differentiation, and increases were correlated with poor histological grades, from well-differentiated to poorly-differentiated SCC. Increased cyclin D1 and p63 expression was associated with the severity of leukoplakia. Based on these results cyclin D1 and p63 products can be a useful tool for improved leukoplakia prognosis.

Immunohistochemical evaluation of p63 and cyclin D1 in oral squamous cell carcinoma and leukoplakia

Objectives

There are only a limited number of studies on cyclin D1 and p63 expression in oral squamous cell carcinoma (OSCC) and leukoplakia. This study compared cyclin D1 and p63 expression in leukoplakia and OSCC to investigate the possible correlation of both markers with grade of dysplasia and histological grade of OSCC.

Materials and Methods

The study included a total of 60 cases, of which 30 were diagnosed with OSCC and 30 with leukoplakia, that were evaluated immunohistochemically for p63 and cyclin D1 expression. Protein expression was correlated based on grades of dysplasia and OSCC.

Results

Out of 30 cases of OSCC, 23 cases (76.7%) were cyclin D1 positive and 30 cases (100%) were p63 positive. Out of 30 cases of leukoplakia, 21 cases (70.0%) were cyclin D1 positive and 30 (100%) were p63 positive (P<0.05).

Conclusion

The overall expression of cyclin D1 and p63 correlated with tumor differentiation, and increases were correlated with poor histological grades, from well-differentiated to poorly-differentiated SCC. Increased cyclin D1 and p63 expression was associated with the severity of leukoplakia. Based on these results cyclin D1 and p63 products can be a useful tool for improved leukoplakia prognosis.

Expression of p63 in potentially malignant and malignant oral lesions

BACKGROUND

p63, a member of p53 family, known to be expressed in embryonic tissues and basal regenerative layers of many epithelial tissues in the adult, is also expressed in various benign and malignant lesions of body including lesions of oral cavity. To evaluate the expression of p63 and compare the expression qualitatively and quantitatively in normal buccal mucosa, epithelial dysplasia, oral submucous fibrosis (OSMF), and oral squamous cell carcinoma (OSCC).

METHODS

The study material consisted of 45 archival cases which were divided into Group I with 5 cases of normal buccal mucosa, Group II with 15 cases of epithelial dysplasia, and Group III with 10 cases of OSMF and 15 cases of OSCC. Immunohistochemical expression of p63 was assessed by using mean, standard deviation, and analysis of variance.

RESULTS

Overexpression of p63 was seen in epithelial dysplasia, OSMF, and squamous cell carcinoma with an increased suprabasal expression in cases of epithelial dysplasia. The mean labeling index (LI) of p63 was found to be in increasing order from normal oral mucosa (33.75%), OSMF (57.37%), epithelial dysplasia (63.87%) to squamous cell carcinoma (69.76%).

CONCLUSION

The results suggest a possible role of p63 in oral carcinogenesis, and an increased LI as well as increased suprabasal expression of this gene in dysplastic lesions may have a potential to be utilized as a marker for premalignancy.

In vitro systems toxicology approach to investigate the effects of repeated cigarette smoke exposure on human buccal and gingival organotypic epithelial tissue cultures

Smoking has been associated with diseases of the lung, pulmonary airways and oral cavity. Cytologic, genomic and transcriptomic changes in oral mucosa correlate with oral pre-neoplasia, cancer and inflammation (e.g. periodontitis). Alteration of smoking-related gene expression changes in oral epithelial cells is similar to that in bronchial and nasal epithelial cells. Using a systems toxicology approach, we have previously assessed the impact of cigarette smoke (CS) seen as perturbations of biological processes in human nasal and bronchial organotypic epithelial culture models. Here, we report our further assessment using in vitro human oral organotypic epithelium models. We exposed the buccal and gingival organotypic epithelial tissue cultures to CS at the air-liquid interface. CS exposure was associated with increased secretion of inflammatory mediators, induction of cytochrome P450s activity and overall weak toxicity in both tissues. Using microarray technology, gene-set analysis and a novel computational modeling approach leveraging causal biological network models, we identified CS impact on xenobiotic metabolism-related pathways accompanied by a more subtle alteration in inflammatory processes. Gene-set analysis further indicated that the CS-induced pathways in the in vitro buccal tissue models resembled those in the in vivo buccal biopsies of smokers from a published dataset. These findings support the translatability of systems responses from in vitro to in vivo and demonstrate the applicability of oral organotypical tissue models for an impact assessment of CS on various tissues exposed during smoking, as well as for impact assessment of reduced-risk products.

Relationship between the epithelial expression of hMLH1, MDM2, and p63 and lower lip carcinogenesis

OBJECTIVES

To evaluate the relationship between the epithelial expression of hMLH1, MDM2, and p63 in lower lip carcinogenesis, comparing the immunostaining of these proteins in cases of actinic cheilitis (AC) and lower lip squamous cell carcinoma (SCC).

STUDY DESIGN

Forty cases of AC and 40 cases of SCC were studied, both lesions were of lower lip. Histological sections of 3 μm were submitted to immunoperoxidase method, and 1000 cells were counted for immunohistochemical analysis of lesions. The results were analyzed quantitatively, and expression was compared by the Mann-Whitney, Student t-test, or one-way ANOVA, adopting a level of significance of 5%.

RESULTS

A higher percentage of epithelial cells expressing hMLH1 was observed in cases of AC without dysplasia or mild dysplasia (721.23 ± 88.116), whereas fewer positive cells were observed in lower lip SSCs (255.03 ± 199.47) when compared to the AC group (P < 0.001). Immunoexpression of MDM2 was higher in SCCs of the lower lip compared with AC (P = 0.019). For p63 protein, the expression was higher in AC than in SCC (P = 0.045).

CONCLUSION

The present results showed changes in the immunoexpression of hMLH1, MDM2, and p63 in epithelial cells from premalignant and malignant lip disease, supporting the hypothesis that these alterations are related to the process of lower lip carcinogenesis.

Can immunohistochemistry serve as an alternative to subjective histopathological diagnosis of oral epithelial dysplasia?

Many attempts have been made to identify objective molecular biomarkers to diagnose and prognosticate oral epithelial dysplasia (OED) because histopathological interpretation is subjective and lacks sensitivity. The majority of these efforts describe changes in gene expression at protein level in OED as determined by immunohistochemistry (IHC). However, the literature on these putative markers of oral cancer progression is vast and varied. The main purpose of this article is to review current knowledge on biomarkers of protein expression for OED by IHC approaches. We further discuss these findings in terms of the proposed essential hallmarks of cancer cells to better understand their role in oral oncogenesis.

Immunohistochemical evaluation of oral epithelial dysplasia using cyclin-D1, p27 and p63 expression as predictors of malignant transformation

OBJECTIVE

To evaluate the degree of expression of cyclin-D1, p27 and p63 in mild, moderate and severe dysplasia using immunohistochemical evaluation in order to illustrate their prognostic value and attempt to propose a molecular grading system for oral epithelial dysplasia.

MATERIALS AND METHODS

The analysis included thirty cases of mild, moderate and severe dysplasia from Department of Oral and Maxillofacial Pathology, Saveetha Dental College, Chennai after a critical review of the Hematoxylin and Eosin (H and E) stained sections. They were subjected to immunohistochemical evaluation using the markers cyclin-D1, p27 and p63. The assessment of the expression based on staining intensity and distribution of immunohistochemical staining of the various markers was analyzed followed by statistical analysis.

RESULTS

A highly significant increase in the expression of cyclin-D1 (P < 0.000) and p63 (P < 0.001) and a moderately significant decrease in the expression of p27 (P < 0.012) with the increasing severity of dysplasia was observed in our study.

CONCLUSIONS

The result of our research affirms the fact that the increase in the expression of markers of cell cycle regulators such as cyclin D1, decrease in the expression of cell cycle inhibitors like p27 and increased expression of p63 in parallel with the increasing severity of dysplasia, emphasizes the use of immunohistochemical markers cyclin D1, p27 and p63 as prognostic markers for better understanding the behaviour of these potentially malignant disorders aiming towards proposing a molecular grading system for oral epithelial dysplasia to enable timely management prior to their possible malignant transformation.

Biomarkers of oral premalignant epithelial lesions for clinical application

Oral cancer is the sixth most common form of cancer worldwide, and the majority of cases occur in India and Southeast Asia. Its major risk factors in the western world include smoking and drinking alcohol, whereas in Asia, it is primarily caused by tobacco/areca nut/betel leaf chewing and/or human papillomavirus (HPV) infections. Little is known about this type of cancer despite recent advances in cancer biology. The generally asymptomatic nature of the early oral lesions causes them to remain undetected in many cases. Thus, the disease progresses substantially before the patients seek treatment and is a major contributing factor to the severity of this disease. Therefore, there is a great need to create awareness for its prevention and early diagnosis. The application of advanced molecular biological and biochemical methodologies to elucidate its biomarkers may aid in early detection; however, much more work must be done for this information to be effectively applied in the clinical setting. This review focuses on the need for systematic diagnoses in the early detection of oral cancer using molecular and biochemical approaches, thereby reducing the number of advanced cases in the chewing tobacco-dominated oral cancer population.

Genetics/epigenetics of oral premalignancy: current status and future research

Squamous cell carcinoma (SCC) of the oral and oropharyngeal region is the sixth most common malignancy in the world today. Despite numerous advances in treatment, long-term survival from this disease remains poor. Early detection can decrease both morbidity and mortality associated with this neoplasm. However, screening for potentially malignant disease is typically confounded by difficulty in discriminating between reactive/inflammatory lesions vs those lesions that are premalignant in nature. Furthermore, the histologic diagnosis of dysplasia can be subjective and is thus prone to a considerable range of interpretation. Similarly, no definitive, validated criteria exist for predicting which dysplastic lesions are most likely to progress to cancer over time. Given this state of science, the presence of dysplasia can only be used to indicate that an oral lesion may have an increased risk of malignant transformation. Molecular biomarkers capable of identifying the subset of lesions likely to progress to cancer are required to eliminate this clinical diagnostic dilemma. The purpose of this review is to assess the current state of knowledge regarding genetic/epigenetic alterations observed in oral mucosal premalignancy. In addition, recommendations for future research studies directed at defining the predictive capacity of specific biomarkers in this modeling are presented.

Tp63 in Oral Development, Neoplasia, and Autoimmunity

The Tp63 gene encodes for multiple isoforms of the p63 transcription factor, a member of the p53 family of proteins. Much like its more famous sibling, the biological role of p63 is quite complex, with wide-ranging effects on development, differentiation, and cellular lineage choices. The crucial function of p63 is epitomized by the striking phenotype of p63 knockout mice. These animals have a profound block in the development of stratified epithelia and aplasia of multiple ectodermal appendages, as well as orofacial clefting and limb defects. Remarkably, a similar spectrum of phenotypic alterations is observed in human syndromes resulting from Tp63 gene mutations. p63 is an important hub in the transcriptional and signaling networks of epithelial cells; thus, it is not surprising that dysregulation of this transcription factor is associated with squamous cell carcinoma. Finally, as a testament to the growing repertoire of p63-associated diseases, autoantibodies to p63 are associated with chronic ulcerative stomatitis, an oral immunologically mediated disease. Over the past decade, our understanding of the broad biologic and pathophysiological roles of p63 has grown significantly. In this review, we discuss the molecular attributes of Tp63 and the clinical consequences of Tp63 dysregulation, particularly as it pertains to oral tissues.

The stem cell code in oral epithelial tumorigenesis: 'the cancer stem cell shift hypothesis'

Tumors of the oral cavity provide an ideal model to study various stages of epithelial tumor progression. A group of cancer cells termed cancer stem cells (CSCs) eludes therapy, persists and initiates recurrence augmenting malignant spread of the disease. Hitherto, accurate identification and separation of such minimal residual cells have proven futile due to lack of identifiable traits to single out these cells from the heterogeneous tumor bulk. In this review we have compiled comprehensive evidence from comparative phenotypic and genotypic studies on normal oral mucosa as well as tumors of different grades to elucidate that differential expression patterns of putative stem cells markers may identify 'minimal residual disease' in oral squamous cell carcinoma. We propose the "cancer stem cell shift hypothesis" to explain the exact identity and switch-over, tumor-promoting mechanisms adapted by putative CSCs with correlation to tumor staging.

DeltaNp63 overexpression, alone and in combination with other biomarkers, predicts the development of oral cancer in patients with leukoplakia

PURPOSE

The risk of malignant transformation of oral preneoplastic lesion (OPL) is difficult to assess. DeltaNp63 is an early oncoprotein associated with mucosal tumorigenesis. The purpose of this study was to assess DeltaNp63 expression in OPL and its role as a marker of oral cancer risk.

EXPERIMENTAL DESIGN

DeltaNp63 expression was determined using immunohistochemistry in 152 OPL patients included in a clinical trial comparing retinyl palmitate alone or plus beta-carotene with low-dose 13-cis-retinoic acid. The associations between DeltaNp63 expression as well as DeltaNp63 expression with other potential risk factors for oral cancer development were analyzed.

RESULTS

DeltaNp63 expression was positive in 41 (27%) patients, clusters of intraepithelial inflammatory cells (EIC) were noted in 37 (26%) patients, and podoplanin (previously reported) was positive in 56 (37%) patients. Significantly more patients whose lesions were DeltaNp63 positive or exhibited EIC developed oral cancers. In the multicovariate analysis including age, treatment, and histologic status as cofactors, positive DeltaNp63 expression was associated with an increased hazard ratio of 3.308 (95% confidence interval, 1.663-6.580; P = 0.0007). Patients whose lesions showed positive DeltaNp63, podoplanin, and EIC had the highest oral cancer risk with a hazard ratio of 4.372 (95% confidence interval, 1.912-9.992; P = 0.0005) and 61% oral cancer development rate at 5 years compared with 15% of other OPL patients (P < 0.0001).

CONCLUSION

DeltaNp63 overepression in OPL is associated with increased oral cancer risk. Together, DeltaNp63, podoplanin, and EIC may be used as biomarkers to identify OPL patients with substantially high oral cancer risk.

Effect of p63 Expression on Survival in Oral Squamous Cell Carcinoma

BACKGROUND

P63 is the protein codified by p63 gene, a p53 gene homolog, known for its pivotal role in cell cycle regulation, and involved in the tumor differentiation. Aims of the present study were to assess the frequency and pattern of p63 protein expression in oral squamous cell carcinoma (OSCC) in relation to the main tumour characteristics and to verify whether p63 can be considered a marker of prognosis in patients with OSCC.

MATERIAL AND METHODS

In a retrospective study, a cohort of 64 OSCC patients was investigated for p63 protein expression and its cellular localization by immunohistochemistry (monoclonal mouse anti-human p63 protein-clone 4A4). After grouping by p63 expression, OSCCs were statistically analyzed for the variables age, gender, histological grading (G), TNM, staging, recurrence, and overall survival rate.

RESULTS

The overall frequency of p63 overexpressed was of 57.8 percent. Various p63 staining patterns were observed according to G score, with a significant correlation between p63 overexpression and the lowest G score (P < 0.0001). No statistically significant difference was found between p63 pattern expression and age, sex, staging. OSCC patients with p63 overexpressed were found to have a poorer survival rate with respect to OSCCs with a normal pattern of expression (P = 0.024).

CONCLUSIONS

On the basis of these results, it is possible to suggest p63 pattern expression as a reliable indicator of histological grading and an early marker of poor prognosis.

Immunohistological evaluation of Ki-67, p63, CK19 and p53 expression in oral epithelial dysplasias

BACKGROUND

Oral squamous cell carcinoma develops through a multistep of genetic mutations, and the process can be morphologically recognized as oral epithelial dysplasia. To evaluate the hypothesis that distributional alterations of proliferating and stem cells may be a useful index to estimate the grading and development of epithelial dysplasia, we examined the distribution patterns according to stratified cell layers.

METHODS

Sixty-two oral dysplasia cases according to the histological grades were immunohistologically examined and the nuclear expression of Ki-67 and p63 antigens was counted according to epithelial layers as labeling index.

RESULTS

The Ki-67 labeling index in the basal and suprabasal layers and that of p63 in the basal layer showed a significant difference between low- and high-grade groups of epithelial dysplasia.

CONCLUSION

The architectural alteration of proliferating cell and stem cell distribution in the layers of epithelial dysplasias may provide useful information to evaluate the grading of oral epithelial dysplasias.

Prognostic value of cyclin D1, p27, and p63 in oral leukoplakia

BACKGROUND

Studies on the expression of genes regulating cell proliferation and apoptosis are essential to help better understand the severity and possible malignant transformation of oral leukoplakia.

METHODS

The characteristics of cyclin D1, p27, and p63 were investigated in this microscopic study, complementing our previous results with Ki67, p53, and the apoptosis index. Clinical and histologic as well as immunohistochemical studies were carried out on oral leukoplakia of 18 patients. Homogenous, or non-homogenous (nodular or speckled) and erythroleukoplakia were determined clinically. Pathologic classification was performed according to the degree of dysplasia. Immunoperoxidase reaction for cyclin D1, p27, and p63 was carried out on the biopsy specimens and the positivity of the reactions was calculated for 1000 epithelial cells.

RESULTS

The expression of cyclin D1 increased in parallel with the severity of leukoplakia. The p27 index was 14-16% in homogenous and nodular leukoplakias but it was substantially lower to 1-2% in erythroleukoplakia. The p63 index was 10% in homogenous, 5% in nodular or speckled, but nearly 20% in erythroleukoplakia, on the average.

CONCLUSION

These results suggest that the characteristic expression of cyclin D1, p27, and p63 in various forms of leukoplakia may be of prognostic value.