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

Biomarkers of malignant transformation in oral leukoplakia: from bench to bedside

Oral leukoplakia is a common precursor lesion of oral squamous cell carcinoma, which indicates a high potential of malignancy. The malignant transformation of oral leukoplakia seriously affects patient survival and quality of life; however, it is difficult to identify oral leukoplakia patients who will develop carcinoma because no biomarker exists to predict malignant transformation for effective clinical management. As a major problem in the field of head and neck pathologies, it is imperative to identify biomarkers of malignant transformation in oral leukoplakia. In this review, we discuss the potential biomarkers of malignant transformation reported in the literature and explore the translational probabilities from bench to bedside. Although no single biomarker has yet been applied in the clinical setting, profiling for genomic instability might be a promising adjunct.

Recurrence in Oral Premalignancy: Clinicopathologic and Immunohistochemical Analysis

Oral leukoplakia (OL) has a propensity for recurrence and malignant transformation (MT). Herein, we evaluate sociodemographic, clinical, microscopic and immunohistochemical parameters as predictive factors for OL recurrence, also comparing primary lesions (PLs) with recurrences. Thirty-three patients with OL, completely removed either by excisional biopsy or by laser ablation following incisional biopsy, were studied. Selected molecules associated with the STAT3 oncogenic pathway, including pSTAT3, Bcl-xL, survivin, cyclin D1 and Ki-67, were further analyzed. A total of 135 OL lesions, including 97 PLs and 38 recurrences, were included. Out of 97 PLs, 31 recurred at least once and none of them underwent MT, during a mean follow-up time of 48.3 months. There was no statistically significant difference among the various parameters in recurrent vs. non-recurrent PLs, although recurrence was most frequent in non-homogeneous lesions (p = 0.087) and dysplastic lesions recurred at a higher percentage compared to hyperplastic lesions (34.5% vs. 15.4%). Lower levels of Bcl-xL and survivin were identified as significant risk factors for OL recurrence. Recurrences, although smaller and more frequently homogeneous and non-dysplastic compared to their corresponding PLs, exhibited increased immunohistochemical expression of oncogenic molecules, especially pSTAT3 and Bcl-xL. Our results suggest that parameters associated with recurrence may differ from those that affect the risk of progression to malignancy and support OL management protocols favoring excision and close monitoring of all lesions.

Oral epithelial dysplasia: Classifications and clinical relevance in risk assessment of oral potentially malignant disorders

After more than a decade, the World Health Organization (WHO) published the revised grading system for oral epithelial dysplasia in 2017. The revised classification has changes reflecting our evolution of understanding of the dysplastic process. Although the WHO 2017 three-tier grading system is the gold standard for histological diagnosis of oral potentially malignant disorders, it has certain limitations. Suggestions to overcome these limitations include the use of clinical determinants and molecular markers to supplement the grading system. It has also been suggested that a two-tier system may be more reproducible and clinically translatable for better management. These advances in the understanding of epithelial dysplasia are very important globally and for us in the Indian subcontinent, given the prevalence of habits (tobacco/areca nut) and burden of oral cancer in this part of the world. The following review traces the evolution of the grading system of dysplasia, its relevance and clinical utility.

Cyclin D1 and Ki-67 expression correlates to tumor staging in tongue squamous cell carcinoma

BACKGROUND

The immunohistochemical expression of Cyclin D1 and Ki-67 were analyzed in tongue squamous cell carcinomas (SCC), relating them to the clinical and morphological exhibition of these tumors.

MATERIAL AND METHODS

Twenty-nine patients fulfilled the inclusion criteria; clinical data included gender, age, ethnicity and use of licit drugs such as alcohol and tobacco. The TNM staging and histopathological differentiation grading was assessed for each case. In addition, T1 patients were gathered with T2 patients; and T3 patients were gathered with T4 patients to assemble two distinct groups: (T1/T2) and (T3/T4).

RESULTS

The mean follow-up time was 24 months and 30% of the patients died as a consequence of the disease, while 23.3% lived with the disease and 46.7% lived lesion-free. T1 and T2 tumors showed statistically lesser Ki-67 and Cyclin D1 staining when compared to T3 and T4 tumors.

CONCLUSIONS

Ki-67 and Cyclin D1 pose as auxiliary tools when determining the progression of tongue SCC at the time of diagnosis.

c-Jun, pc-Jun, and p27 are differently expressed in oral leukoplakias in smokers and never-smokers

OBJECTIVE

Oral cancer may be preceded by potentially malignant lesions, and smoking is a risk factor. Oral leukoplakia (OL), which is the most common among these lesions, is defined by the World Health Organization as "a white plaque of questionable risk having excluded known diseases or disorders that carry no increased risk for cancer." Thus, OL is a clinical diagnosis used to designate oral white lesions, which are histologically represented by hyperkeratosis associated or not associated with epithelial dysplasia. It is known that c-Jun and pc-Jun have a role in cell proliferation and that p27 is decreased during carcinogenesis; thus, the aim of this study was to investigate whether these proteins are differently expressed in OL in smokers and never-smokers.

STUDY DESIGN

Seventy-three cases diagnosed as OL were selected and divided into four groups according to the presence or absence of dysplasia and patients' smoking status (smokers: 39 cases, 24 dysplastic; never-smokers: 34 cases, 20 dysplastic). The immunoexpressions of c-Jun, pc-Jun, and p27 were evaluated.

RESULTS

A significant correlation between smoking condition and the percentages of c-Jun (P = .0356) and pc-Jun (P = .0216) was found and was more intense in cases that underwent malignant transformation (6/47).

CONCLUSIONS

Smoking habits may be linked to the expression of proteins directly associated with cell cycle progression.

β-catenin in oral cancer: an update on current knowledge

β-Catenin is a multiple function protein. These functions derive from its interactions with other cell proteins, both on the cell membrane, in the cytoplasm and in the nucleus. β-Catenin forms a complex with the adhesion molecule E-cadherin, promoting cell-cell adhesion and thereby preventing the cell dissociation that is required for cancer invasion and progression mechanisms. There is also a dynamic pool of cytoplasmic β-catenin that serves as connection between the extracellular microenvironment and the nucleus. Cytoplasmic β-catenin acts as a transcription factor for the nucleus in the canonical Wnt pathway, activating the transcription of various genes. Structural or functional alterations of β-catenin can promote cancer progression. This review addresses the current knowledge on the implications of β-catenin in the development of oral cancer.

Potentially malignant disorders of the oral cavity: current practice and future directions in the clinic and laboratory

Despite commendable progress in the prevention, detection, and treatment of a wide variety of solid tumor types, oral squamous cell carcinoma (OSCC) remains a significant health burden across the globe. OSCC carcinogenesis involves accumulation of genetic alterations that coincide with the multistep malignant transformation of normal oral epithelium. OSCC is often first diagnosed at late stages of the disease (advanced regional disease and/or metastasis). Delayed diagnosis precludes successful treatment and favorable outcomes. In clinical practice, opportunities exist to identify patients with oral potentially malignant disorders (OPMDs), which precede the development of cancer. This review addresses the current status of laboratory and clinical research on OPMDs, with emphasis on leukoplakia and erythroplakia. OSF is also presented, though there is a paucity of published studies on this disorder. We focus on findings that could translate into earlier diagnosis and more efficacious treatment of those lesions with significant malignant potential. We explore how markers of OPMD malignant transformation might be implemented into current diagnostic practice to help clinicians objectively stratify patients into treatment/follow-up groups according to relative risk. We provide an overview of recently concluded and ongoing OPMD chemoprevention trials. We describe laboratory OPMD models that can be used to not only to reveal the genetic and molecular intricacies of oral cancer but also to develop novel screening methods and therapeutic approaches. Finally, we call for targeted screening programs of at-risk populations in order to facilitate diagnosis and treatment of OPMD and early OSCC.

Management for premalignant lesions of the oral cavity

Premalignant lesions of the oral cavity present as visibly abnormal areas of mucosa and may be a source of significant anxiety for the patient and the clinician. Suspicious lesions should be biopsied to evaluate for dysplasia. The risk of malignant transformation may relate to patient characteristics, environmental risk factors and genetic alterations. Management of such lesions hinges on risk modification, surveillance, symptom management and directed biopsies. Excision or ablation of dysplastic lesions is indicated. We review the current evidence relating to management of premalignant lesions of the oral mucosa and make recommendations for practice patterns.

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.

Immunohistochemical expression of EGFR in oral leukoplakia: association with clinicopathological features and cellular proliferation

Objectives: to investigate the immunoexpression of epidermal growth factor receptor (EGFR) in a sample of oral leukoplakias (OL) and to determine the receptor’s association with dysplasia, tobacco consumption, lesion site, and proliferation rate. Although EGFR should be overexpressed in some oral leukoplakias, the factors that may interfere with this expression and the influence of this receptor on epithelial proliferation have yet to be investigated. Study Design: Samples of oral leukoplakias (48) and of normal oral epithelium (10) were immunohistologically examined for expression of EGFR. Immunohistochemistry for Ki-67, and p27 were also performed in leukoplakias. EGFR expression was associated with clinical and pathological features. Results: EGFR was positive in 62.5% of the leukoplakias and 50% of normal oral epithelium. The number of EGFR positive OL located in high-risk sites was significantly higher than EGFR positive OL located in low-risk sites. Most of the p27 negative leukoplakias were EGFR positive, and the p27 index in the parabasal layer was diminished in the presence of dysplasia. Positivity for EGFR was not associated with dysplasia, tobacco exposure, or Ki-67. Conclusion: EGFR is expressed in leukoplakia regardless of dysplasia, but EGFR positivity should be more frequent in lesions sited in areas of high cancer risk. The association between EGFR and p27 may represent an important mechanism in the control of cellular proliferation and malignant progression of oral epithelium and therefore warrants further investigation.

Key words:Oral leukoplakia, EGFR, p27, Ki-67, epithelial dysplasia.

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.

Potentially malignant disorders of the oral and oropharyngeal mucosa; terminology, classification and present concepts of management

In a recently held WHO workshop it has been recommended to abandon the distinction between potentially malignant lesions and potentially malignant conditions and to use the term potentially malignant disorders instead. Of these disorders, leukoplakia and erythroplakia are the most common ones. These diagnoses are still defined by exclusion of other known white or red lesions. In spite of tremendous progress in the field of molecular biology there is yet no single marker that reliably enables to predict malignant transformation in an individual patient. The general advice is to excise or laser any oral of oropharyngeal leukoplakia/erythroplakia, if feasible, irrespective of the presence or absence of dysplasia. Nevertheless, it is actually unknown whether such removal truly prevents the possible development of a squamous cell carcinoma. At present, oral lichen planus seems to be accepted in the literature as being a potentially malignant disorder, although the risk of malignant transformation is lower than in leukoplakia. There are no means to prevent such event. The efficacy of follow-up of oral lichen planus is questionable. Finally, brief attention has been paid to oral submucous fibrosis, actinic cheilitis, some inherited cancer syndromes and immunodeficiency in relation to cancer predisposition.

Nuclear localization of beta-catenin involved in precancerous change in oral leukoplakia

Background

Oral leukoplakia is a precancerous change developed in the oral mucosa, and the mechanism that oral leukoplakia becomes malignant through atypical epithelium is not known. Here we compared the β-catenin expression detected by immunohistochemical staining in the normal oral epithelium and in the oral leukoplakia with or without dysplasia.

Results

The normal oral epithelium showed β-catenin expression only in the cell membrane, but not in the nuclei. In the oral leukoplakia without dysplasia, 7 out of 17 samples (41%) showed β-catenin expression in the cell membrane, and 5 samples (29%) showed expression in the nuclei. In the oral leukoplakia with dysplasia, nuclear expression of β-catenin was shown in 11 out of 12 samples (92%). Incidence of nuclear β-catenin expression was significantly different between dysplasia and normal oral epithelium (P < 0.01), and also between oral leukoplakia with dysplasia and those without dysplasia (P < 0.01). Wnt3 expression was detected in the epithelial cell membrane or cytoplasm in oral leukoplakia where nuclear expression of β-catenin was evident, but not in epithelial cells without nuclear expression of β-catenin.

Conclusion

The components of canonical Wnt pathway, such as Wnt3, β-catenin, and cyclin D1, were detected, implying that this pathway is potentially involved in the progression of dysplasia in oral leukoplakia.