Oral premalignant lesions: from the pathological viewpoint

Oral epithelial dysplasia: Recognition, grading and clinical significance

Histopathological grading of epithelial dysplasia remains the principal laboratory method for assessing the risk of malignant transformation in oral potentially malignant disorders (OPMDs). Current views on the molecular pathogenesis and histological interpretation of the features of epithelial dysplasia are described, and the use of grading systems for epithelial dysplasia is discussed. Changes to the current 2017 WHO criteria for diagnosis are proposed with emphasis on the architectural features of epithelial dysplasia. The predictive values of three-grade and binary systems are summarised, and categories of epithelial dysplasia are reviewed, including lichenoid and verrucous lesions, keratosis of unknown significance, HPV-associated dysplasia, differentiated and basaloid epithelial dysplasia. The implications of finding epithelial dysplasia in an oral biopsy for clinical management are discussed from the pathologists' viewpoint.

A Case Report of Tongue Lymphoepithelial Carcinoma with a Histological Diagnostic Dilemma

Most head and neck lymphoepithelial carcinomas (LECs) arise in the nasopharynx and harbor Epstein–Barr virus (EBV). LEC is also a rare subtype of the oral squamous cell carcinoma (SCC). Morphologically, LEC is defined as resembling non-keratinizing nasopharyngeal carcinoma, undifferentiated subtype. The histological features and pathogenesis of oral LEC are not established. We describe a case of tongue LEC with histopathological diagnostic difficulties. A 72-year-old Japanese female presented with a whitish change on her left-side tongue. The diagnosis was atypical epithelium; neoplastic change could not be ruled out by a biopsy. Although the lesion was monitored at our hospital per her request, invasive carcinoma was detected 11 months later. Microscopically, conventional SCC was observed with the characteristic features as LEC confined to the deep part of the lesion. We briefly discuss this unusual histological finding and make a novel proposal for distinguishing oral LEC from LECs in other regions based on these histological findings.

Oral Potentially Malignant Disorders (OPMD): What is the clinical utility of dysplasia grade?

INTRODUCTION

Oral epithelial dysplasia is considered a potential histologic precursor of subsequent squamous cell cancer. As standard clinical practice, pathologists grade dysplasia to assess risk for progression to malignancy. Except for the most advanced grade, severe dysplasia, dysplasia grading has failed to correlate well with the risk to develop invasive cancer. The questions of what process dysplasia grading best represents and what clinical utility dysplasia grading may have are explored.

AREAS COVERED

This narrative review is based on PubMed search with emphasis on papers since 2010. Epithelial dysplasia as a precursor lesion of cancer and dysplasia grading as a risk assessment tool for progression to cancer are discussed. The close clinical association of dysplasia with known carcinogens, alcohol, and tobacco products is presented.

EXPERT OPINION

Oral epithelial dysplasia is often, associated with prolonged exposure to tobacco and alcohol products. With reduction of carcinogen exposure, dysplasia is known to regress in some cases. It is proposed that histologic dysplasia grade together with macroscopic images of dysplastic clinical lesions be used as an educational tool to incentivize patients to reduce their known carcinogen exposure. This strategy has the potential to reduce lesion progression thereby reducing the disease burden of oral cancer.

The impact of close surgical margins on recurrence in oral squamous cell carcinoma

BACKGROUND

Close margins influence treatment and outcome in patients with oral squamous cell carcinoma (OSCC). This study evaluates 187 cases of surgically treated OSCC regarding the impact of close margins on recurrence-free survival (RFS) and disease-specific survival (DSS).

METHODS

Predictors of worsened outcome were identified using Kaplan-Meier analysis and multivariate Cox regression analysis.

RESULTS

Tumour size [HR:1.70(0.95-3.08)], nodal status [HR:2.15(1.00-4.64)], presence of extracapsular spread (ECS) [HR:6.36(2.41-16.74)] and smoking history [HR:2.87(1.19-6.86)] were associated with worsened RFS. Similar factors were associated with worsened DSS. Close margins did not influence RFS or DSS.

CONCLUSIONS

While most conventional risk factors for OSCC conferred a worsened outcome, close margins did not. One explanation for this would be that close margins (< 5 mm) are equivalent to clear margins and the cutoff definition for a close margin should be re-evaluated. Lack of standardized pathology could also reduce accuracy of reporting of close surgical margins.

Current challenges and the diagnostic pitfalls in the grading of epithelial dysplasia in oral potentially malignant disorders: A review

Oral cancer is one of the common cancers in the world causing high morbidity. Development of cancer is preceded by certain asymptomatic clinical lesions and conditions all together known as 'oral potentially malignant disorders'. Histologically they are represented by the term 'oral epithelial dysplasia'. The degree of severity of dysplasia is determined in the form of 'grade'. Despite the existence of several grading systems proposed by various scholars, it is still a challenging task for the Pathologists to grade dysplasia accurately for the proper diagnosis of the disease and to follow preferable treatment plans. This review aims to focus on the current challenges and the diagnostic pitfalls in the grading of oral epithelial dysplasia in various oral potentially malignant disorders.

Prognostic value of the immunohistochemical detection of epithelial-mesenchymal transition biomarkers in oral epithelial dysplasia: A systematic review

BACKGROUND

Oral potentially malignant disorders (OPMDs) comprise a range of clinical-pathological alterations that are frequently characterized as architectural and cytological derangements upon histological analysis. Epithelial-mesenchymal transition (EMT) has been proposed as a critical mechanism for the acquisition of the malignant phenotype in neoplastic epithelial processes. This study aims to systematically review the current findings on the immunohistochemical expression of epithelial-mesenchymal transition markers in oral potentially malignant disorders and to evaluate their possible application as biomarkers associated with the progression of oral epithelial dysplasias.

MATERIAL AND METHODS

A systematic search was performed in the following databases: PubMed, EMBASE, Chinese BioMedical Literature Database, and Cochrane Library. Articles that evaluated the relationship between the expression of EMT markers and the degree of oral epithelial dysplasia were selected for the systematic review. The quality of each eligible study was evaluated by independent reviewers that used operationalized prognostic biomarker reporting guidelines (REMARK).

RESULTS

Seventeen articles met all inclusion criteria and were selected. The EMT markers analyzed exhibited an important association with the prognosis of the cases evaluated. The results showed a progressive increase in the expression of nuclear transcription factors and markers of mesenchymal differentiation, as well as negative regulation of epithelial and cell adhesion markers, according to the stage of oral epithelial dysplasia.

CONCLUSIONS

The dysregulation of expression of important EMT components in oral dysplastic epithelium is a potential prognostic marker in OPMDs.

Human papilloma virus genotypes in dysplasia and epithelial hyperplasia of oral cavity using the luminex xmap technology. A multicenter study

Background

Oral cancer associated with high risk (HPV-HR) human papilloma virus (HPV) has been increasing. HPV-HR has been associated with epithelial dysplasia, however, little information exists on its frequency in epithelial hyperplasia lesions. The aim of this study is to compare HPV genotypes in dysplastic and hyperplastic lesions of oral cavity.

Material and Methods

Two hundred and fifty oral lesions: 131 dysplasia and 119 hyperplasia from two regions of Colombia were evaluated. One hundred seventy-four coming from urban area and 104 from a high risk population to oral cancer from a rural area. HPV was identified by qPCR and Twenty-four HPVs genotypes were evaluated by Luminex® technology. Logistic regressions were performed to establish the associations between HPV infections with oral dysplasia.

Results

Twenty-eight percent (70/250) of the samples were positives for any HPV and HPV-HRs were more frequently than low risk HPVs. HPV-16 was the most detected genotype (16%) followed by HPV-31, 53, 18 and 45. HPV, HPV-HRs and HPV-16 were only associated with dysplasia in urban area; OR 3.28 (CI 95% 1.49-7.17), OR 7.94 (CI 95% 2.97-21.2) and OR 5.90 (CI 95% 2.05-17). Individuals in rural area showed more HPV and HPV-HRs infection in hyperplasic lesions than urban population. The majority of HPV+ lesions had multi-type of HPV (52/70) and the urban individuals showed more genotypes than rural population.

Conclusions

HPV-.HRs are frequently found in hyperplastic and dysplastic epithelial lesions. HPV-HRs and HPV-16 were associated with dysplasia in urban population. Rural high risk population and urban population differ in the frequency and variety of HPV genotypes.

Key words:Human papilloma virus, epithelial dysplasia, epithelial hyperplasia, HPV-genotypes.

Intraoral confocal microscopy of suspicious oral lesions: a prospective case series

BACKGROUND

Oral squamous cell carcinoma (OSCC) accounts for more than 90% of oral epithelial malignancies and often arises from precursor lesions, whose diagnosis is based on biopsy and histopathology. In vivo reflectance confocal microscopy (RCM) images the vital tissues at microscopic resolution, well correlating with conventional histopathology, but it is poorly investigated in oral oncology. The present work aims to describe RCM cytoarchitectural findings in oral mucosae affected by OSCC and its precursors.

MATERIALS AND METHODS

A series of clinically suspected oral lesions underwent RCM imaging before conventional biopsy and histopathological assessment in order to identify features suggestive of tumoral changes. Sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV) of RCM compared to histopathology were calculated.

RESULTS

Totally, 30 sites in 20 patients were considered and clinically classified into 16 "leukoplakia"/" traumatism", nine erosive-ulcerative lesions, three verrucous lesions, and two healthy mucosae, as control. The histopathological "positivity," due to the presence of various degrees of dysplasia and/or neoplasia, was found in 11 lesions; the RCM "positivity" was referred to nine lesions reporting the RCM detection of polymorphism, multinucleated cells, irregular cellular maturation, altered nuclear/cytoplasm ratio, and abnormal blood vessels. After excluding three verrucous lesions from the RCM analysis, due to the low laser penetration through the hyperkeratotic layers, the results well correlated with histopathology, reporting 1.000 (SE), 0.933 (SP), 0.909 (PPV), and 1.000 (NPV).

CONCLUSION

RCM can reveal dysplastic/neoplastic signs occurring in oral lesions, thus supporting their diagnostic pathway.

Cytokeratin 19 Immunostain Reduces Variability in Grading Epithelial Dysplasia of the Non-Keratinized Upper Aerodigestive Tract Mucosa

Epithelial dysplasia (ED) grading systems are criticized for low reliability. The effects of diagnostic tests or stains on reducing examiner variability in grading ED of the upper aerodigestive tract have not been investigated. The study aim was to examine the effectiveness of cytokeratin 19 (K19) immunostain on enhancing inter and intraexaminer reliability of ED grading and to reiterate the relation of K19 positivity with epithelial keratinization. The study sample consisted of 122 paraffin blocks that fulfilled the inclusion criteria. Each paraffin block had three sections cut: one immunostained for K19 and two for hematoxylin and eosin stain (H&E). Each examiner graded the study sample in six rounds; three using H&E stain only and three using paired K19-H&E stains. The study examiners were three American-Board certified practicing oral pathologists. The results were analyzed using Krippendorff's alpha, ROC curve, Chi square test and binary logistic regression. Upon the use of paired K19-H&E stains the results showed that the intraexaminer reliability coefficients of grading were improved from 0.70, 0.69, 0.78 to 0.73, 0.88, 0.91 for examiners 1, 2, and 3 respectively. Reliability coefficients for inter-examiners improved from 0.55 to 0.73 (Krippendorff alpha). The accuracy of identifying the diseased cases (high-grade dysplasia) increased from 0.82 to 0.94 (ROC curve). Binary logistic regression revealed that K19 positivity is negatively associated with hyperkeratinization of surface epithelium (P = 0.001). To conclude, for grading non-keratinized epithelial dysplastic lesions of the upper aerodigestive tract, paired K19-H&E stains proved to reduce inter and intra-examiner variability by highlighting the extension of dysplastic epithelial cells within epithelial thickness, thus identifying the involved epithelial third and assigning a more reliable and better reproducible grade.

Evaluation of the chemopreventive effects of Ankaferd Bloodstopper in 7,12-dimethylbenz[a]anthracene-induced oral epithelial dysplasia

OBJECTIVES

Ankaferd BloodStopper® (ABS) is an herbal extract which has been used historically as a hemostatic agent in traditional Turkish medicine. ABS comprises of standardized mixture of herbs Thymus vulgaris, Glycyrrhiza glabra, Vitis vinifera, Alpinia officinarum, and Urtica dioica. In addition to its hemostatic effects, the herb ABS contains some other biological effects including antioxidant and antitumoral properties. The aim of this study is to investigate the chemopreventive effects of ABS in 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral epithelial dysplasia.

MATERIALS AND METHODS

A total of 40 Sprague Dawley rats were randomly divided into four groups. Group 1 animals received DMBA alone, and group 2 animals received both DMBA and Ankaferd. Group 3 animals received ABS alone while group 4 animals served as control group and received only liquid paraffine. All animals were sacrificed, and tissue samples were analyzed histologically at the end of the experimental period (14 weeks).

RESULTS

Histological studies have shown that the buccal pouches of animals treated with DMBA alone revealed severe dysplasia while only mild or no dysplasia were noticed in DMBA + ABS group. Ankaferd were administered to animals and control group showed no dysplasia or other oral lesions.

CONCLUSION

The results suggest that Ankaferd Bloodstopper® has chemopreventive effect against DMBA-induced oral epithelial dysplasia.

CLINICAL RELEVANCE

Ankaferd Bloodstopper® could be used as a supportive treatment option of cancer in oral and maxillofacial surgery since it possesses chemopreventive effect.

Evaluation of Mast Cell Density in the Tumor Microenvironment in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

The objective of this study was to compare mast cell density (MCD) in oral epithelial dysplasias (OED) and oral squamous cell carcinoma (OSCC) and determine its correlation with clinical and histopathologic parameters and the degree of tumor differentiation. Thirty OSCC samples, 14 OED samples, and 4 non-neoplastic oral mucosa samples were analyzed by immunohistochemistry to determine MCD based on the expression of MC tryptase. In addition, MCs were categorized morphologically into degranulated and granulated cells. MCD was significantly higher in OSCC lesions with a greater degree of differentiation (P=0.04). No significant difference in MCD was detected between mild and moderate OED samples (P=0.09). Our findings indicate that MCs are present in the tumor microenvironment and may be associated with a better prognosis.

Analysis of images for detection of oral epithelial dysplasia: A review

This paper provides a review of various image analysis approaches that have been previously used for recognition of dysplasia in images of the epithelium of the oral cavity. This domain has become especially admissible with the uncovering of the importance of image analysis which can probably be an aid to subjective diagnosis by histopathologists. Oral malignancy is a rampant form of cancer found among people of the Indian subcontinent due to various deleterious habits like consumption of tobacco, areca nut, betel leaf etc. Oral Submucous Fibrosis, a precancer, whose pathological category falls between normal epithelium and epithelial dysplasia, is caused because of these habits and can ultimately lead to oral cancer. Hence early detection of this condition is necessary. Image analysis methods for this purpose have an enormous potential which can also reduce the heavy workload of pathologists and to refine the criterion of interpretation. This paper starts with a critique of statistics of oral carcinoma in India and distribution of cancer in intra-oral sites and moves on to its causes and diagnostic approaches including causative agents, problems in curative approach and importance of image analysis in cancer detection. The various image analysis methods to appraise the cytological and architectural changes accompanied by Oral Epithelial Dysplasia in the images of the oral epithelial region have been described in relation to 2005 WHO Classification System and it was found that in future, analysis of images based on the mentioned methods has the potential in better interpretation and diagnosis of oral carcinoma.

Inter- and Intra-Observer Variability in Diagnosis of Oral Dysplasia

Background:

Oral potentially malignant disorders (OPMDs) are lesions from which malignancy is more likely to develop that from other tissues. The potential for malignant transformation of OPMDs is estimated by determining the degree of dysplastic changes in the epithelium. Dysplasia grading has been criticized for lack of reproducibility and poor predictive value but is still considered the gold standard for diagnosing OPMDs. Since grading of dysplasia is based on architectural and cytological changes, there can be considerable inter- and intra-observer variability due to subjective impressions. This aim in this study was to assess the degree of agreement between two pathologists grading dysplasia in the same patients and review the existing grading system.

Materials and Methods:

In this hospital-based cross-sectional study, 100 patients with clinically diagnosed OPMDs were subjected to biopsy followed by histopathological examination. The slides were examined by two pathologists using WHO and binary systems of classification and both were blinded to the clinical and each other’s histological diagnosis. For statistical analysis the Chi square test was applied.

Results:

Statistical analysis showed poor inter-observer variability with P values of 0.8 using the WHO classification and 0.3 using the binary classification.

Conclusion:

Our study provides evidence that the existing systems for grading dysplasia are not competent to rule out subjectivity. There is a need for a classification system that can overcome this drawback.

Photodynamic therapy in oral potentially malignant disorders-Critical literature review of existing protocols

INTRODUCTION

Oral cancer is a serious public health issue. Apart from its high rate of prevalence, incidence and mortality, it can often result in more complex and expensive treatment when diagnosed late. Potentially malignant disorders (PMDs) can precede oral cancer, and are usually treated by surgical excision. However, in many cases patients are elderly and multiple interventions may be required. Photodynamic therapy (PDT) is a simple alternative, which has been successfully used in the treatment of oral PMDs.

OBJECTIVE

Due to the lack of standardization regarding photosensitizers (PTSs), types of irradiation, and methods of application, the objective of this study was to analyze existing PDT protocols in an attempt to identify the one that demonstrates greater efficiency, reliability and feasibility in the treatment of oral PMDs for both researchers and clinicians.

METHODS

Original clinical studies published only in English between 1993 and 2016 were searched in Pubmed/Medline database using the following keywords: photodynamic therapy; oral potentially malignant disorder; oral premalignant lesions. Review articles; experimental studies; case-reports; commentaries; and letters to the Editor were excluded from the selection.

RESULTS AND CONCLUSION

Based on the 16 studies selected, the topical 5-ALA-20% PTS, associated to a LED light applied for 15min with a 7-day interval between sessions emerged as the most frequently used PDT protocol, with satisfactory results. Due to its low rate of side effects, this PDT protocol presents good potential for the treatment of oral PMDs. Further clinical studies are required to ascertain its long-term validity in preventing oral cancer.

Correlation between immunohistochemical staining of CEACAM1 and clinicopathological findings in oral pre-neoplastic lesions and squamous cell carcinoma

Squamous cell carcinoma of the oral cavity represents the sixth most common cancer worldwide and it is often preceded by pre-neoplastic lesions. Sometimes it is still difficult for pathologists to make objective differential diagnoses only on histological characteristics. Tumorigenesis is accompanied by altered expression of cell adhesion molecules, like carcinoembryonic antigen cell adhesion molecule (CEACAM)1. We wanted to investigative CEACAM1 in oral dysplastic lesions, carcinoma in situ (CIS) and oral squamous cell carcinoma (OSCC). We examined immunohistochemical CEACAM1 expression in 50 OSCC, 30 oral CIS and 40 pre-neoplastic lesions and assessed its correlation with clinical and pathological parameters. CEACAM1 was not expressed in normal mucosa, significantly expressed in CIS while it was negative in all the dysplastic lesions. In OSCC, high CEACAM1 expression was associated with tumor grade and inversely correlated with both overall and disease-specific 5-year survival. We showed that CEACAM1 expression is very dynamic: absent in dysplastic lesions, up-regulated in CIS and OSCC. We suggest that CEACAM1 could be a prognostic marker of OSCC and oral CIS. Our most important finding was that it could help pathologists diagnosing oral carcinoma in situ.

Programmed death ligand 1 (PD-L1) expression and tumor microenvironment: Implications for patients with oral precancerous lesions

OBJECTIVES

Cancer immunoediting represents a relatively novel concept attempting to explain the process of tumor escape from the host immune system response. Here, we attempted to elucidate the role of programmed death ligand 1 (PD-L1), the tumor microenvironment, and tumor escape mechanisms that allow malignant transformation of oral precancerous lesions.

MATERIALS AND METHODS

Patients with oral precancerous lesions managed at the Nara Medical University Hospital, Japan, (n=120) were enrolled in this study. Epithelial dysplasias were graded by experienced pathologists, and subepithelial PD-L1-, CD163-, and CD8-positive cells were counted in the superficial lamina propria of oral mucosa. Epithelial PD-L1 expression was evaluated according to the staining intensity. The association of clinicopathological factors with epithelial dysplasia, malignant-free survival time, and significance of risk factors for malignant transformation were determined.

RESULTS

Multivariate analysis showed that the subepithelial CD163-positive cell count was the only significant risk factor for high-grade epithelial dysplasia (P<0.001), while subepithelial CD163- and PD-L1-positive cell counts, and epithelial PD-L1 positivity were significantly associated with malignant-free survival (P=0.004, 0.04, and <0.001, respectively). Subepithelial PD-L1-positive cell count and epithelial PD-L1 positivity were significantly associated with malignant transformation (P=0.01 and 0.04, respectively).

CONCLUSION

Our results indicate that PD-L1-expressing dysplastic epithelial and recruited subepithelial cells in oral precancerous legions may evade the host immune system, and that the inhibition of PD-1/PD-L1 pathway may potentially prevent malignant transformation of oral precancerous legions as well as can treat advanced cancers.

[Precancerous lesions of the buccal epithelium]

Squamous cell carcinomas of the oral cavity and lips consistently have a high incidence (they constitute the fifth most common form of cancer in France) and carry a heavy prognosis, particularly if diagnosed late. According to different studies, between 10 and 80% of such carcinomas occur in a pre-existing or precancerous lesion. The World Health Organisation (WHO) recommends the use of two terms for such lesions: precursor lesions, i.e. histological lesions associated with intraepithelial neoplasia (IEN) and verrucous hyperplasia (VH), frequently resulting clinically in leukoplakia or erythroplakia; "at risk" lesions, which include lichen planus, submucosal oral fibrosis and certain forms of genodermatosis.

Inter- and intra-observer variability in three grading systems for oral epithelial dysplasia

Background and Objectives:

Management of oral premalignant lesions depends on clinical assessment and grading of oral epithelial dysplasia (OED), which remains one of the most important predictors of malignant potential. Numerous grading systems for OED exists with varying sets of assessing criteria and are largely considered subjective. The present study attempted to assess the inter- and intra-observer variability in three grading systems: Binary system, WHO (2005) and Ljubljana systems.

Methodology:

Histopathological grading of 63 cases of leukoplakia was performed by two oral pathologists and one general pathologist, who were blinded, using all the three grading systems at different time intervals and was repeated twice. Inter- and intra-observer variability was then evaluated by multivariate kappa analysis.

Results:

Inter-observer agreement in the two set of observations was found to be “slight” in WHO (k = 0.001 and 0.039), “slight” and “poor” in binary (k = 0.108 and −0.007), “poor” and “slight” in Ljubljana's (k = −0.027 and 0.106) grading systems. Intra-observer agreement ranged from “slight” to “fair” (k = 0.128 and 0.295) in WHO, “fair” to “moderate” (k = 0.224 and 0.420) in binary and “slight” to “fair” (k = 0.161 and −0.353) in Ljubljana's grading systems.

Conclusions:

The binary system of classification proved to have an overall better inter- and intra-observer agreement. This study also showed better intra-observer agreement in all the grading systems as well as in individual histopathological parameters. Defining the individual parameters more objectively with the reproducible structuring of the grading systems and training of the pathologists would help reduce the variability in diagnosing dysplasia.

Disordered arrangements of basal cells as a prognostic factor for oral epithelial dysplasia: a morphometric study of 96 cases

OBJECTIVE

The aim of this study was to assess objectively the predictive value of the atypical appearance of the basal layer of oral epithelial dysplasia (OED) for development into invasive carcinoma.

STUDY DESIGN

Ninety-six OED cases were examined. These cases were divided into 2 groups: 38 cases that developed into invasive carcinoma and 58 cases that did not. Furthermore, 12 histopathological factors were quantified morphometrically in each case and assessed by Cox's proportional hazards model.

RESULTS

The standard deviation of the length between the apical membrane of the basal cells and the basement membrane was significantly associated with development of OED into invasive carcinoma (P < .001; hazard ratio, 3.124).

CONCLUSION

We provided novel, objective data demonstrating that an atypical appearance, especially the disordered arrangement of the basal cells representing loss of polarity, may be useful for predicting the development of OED into invasive carcinoma of the tongue.

Immunohistochemical staining patterns of cytokeratins 13, 14, and 17 in oral epithelial dysplasia including orthokeratotic dysplasia

Diagnosis of the exact grade of oral epithelial dysplasia is difficult, and interobserver variations in grading are common. The aim of this study was to investigate the expression patterns of cytokeratins (CKs) in dysplastic oral epithelia, to identify useful double immunostaining diagnostic markers. Immunoexpression of CK13, CK14, CK17, and Ki-67 were investigated in 21 normal epithelial specimens and 146 epithelial dysplasia specimens. In epithelial dysplasia specimens, orthokeratotic dysplasia (OKD) was identified using CK10 immunostaining. Most mild dysplasia specimens were CK13+ and CK17-. In moderate dysplasia, CK13 expression tended to be lower and CK17 expression tended to be higher than in mild dysplasia. All carcinoma in situ (CIS) specimens were CK17+. In differentiated type CIS specimens, CK13 expression was weakly positive. Most epithelial dysplasia specimens were CK14+. There were no significant differences in the expression patterns of CKs between OKD and non-OKD specimens in any of the grades of dysplasia. These results indicate that CK14 expression can be used to detect early epithelial dysplasia, and that CK13 and CK17 expression are useful for detecting neoplastic changes.

Multivariate analyses of Ki-67, cytokeratin 13 and cytokeratin 17 in diagnosis and prognosis of oral precancerous lesions

BACKGROUND

Ki-67, cytokeratin 13, and/or cytokeratin 17 detection by immunohistochemistry has been reported to be useful for the diagnosis of oral precancerous lesions. However, the use of these markers remains controversial because of the lack of appropriately designed statistical studies. We assessed the hypothesis that Ki-67, cytokeratin 13, or cytokeratin 17 immunohistochemistry could facilitate the diagnosis of oral precancerous lesions and/or predict prognosis.

METHODS

Epithelial dysplasia was classified as low grade (none or mild dysplasia) or high grade (moderate dysplasia, severe dysplasia, or carcinoma in situ). This study included 58 low-grade and 36 high-grade dysplasia cases. We used logistic regression to assess the diagnostic values of Ki-67, cytokeratin 13, and cytokeratin 17 for high-grade dysplasia. Correlations between these markers and the prognosis of oral atypical epithelium were assessed using the Cox proportional hazards model.

RESULTS

Ki-67 overexpression and cytokeratin 13 loss were independent diagnostic markers for high-grade dysplasia (odds ratios, 1.92 and 2.53; 95% confidence intervals, 1.03-3.58, and 1.19-5.38, respectively). The area under the curve of Ki-67 was 0.73 and that of cytokeratin 13 was 0.72. However, the combination of Ki-67 and cytokeratin 13 yielded the area under the curve of 0.78. Ki-67 overexpression was significantly associated with recurrence and/or malignant transformation of oral atypical epithelium (hazard ratio, 7.25; 95% confidence interval, 1.07-48.92).

CONCLUSIONS

Ki-67 overexpression and cytokeratin 13 loss may be useful for distinguishing oral precancerous lesions from reactive atypical epithelium. Moreover, Ki-67 overexpression may be a risk factor for recurrence and/or malignant transformation of oral atypical epithelium.

Utility of models of the gastrointestinal tract for assessment of the digestion and absorption of engineered nanomaterials released from food matrices

Engineered metal/mineral, lipid and biochemical macromolecule nanomaterials (NMs) have potential applications in food. Methodologies for the assessment of NM digestion and bioavailability in the gastrointestinal tract are nascent and require refinement. A working group was tasked by the International Life Sciences Institute NanoRelease Food Additive project to review existing models of the gastrointestinal tract in health and disease, and the utility of these models for the assessment of the uptake of NMs intended for food. Gastrointestinal digestion and absorption could be addressed in a tiered approach using in silico computational models, in vitro non-cellular fluid systems and in vitro cell culture models, after which the necessity of ex vivo organ culture and in vivo animal studies can be considered. Examples of NM quantification in gastrointestinal tract fluids and tissues are emerging; however, few standardized analytical techniques are available. Coupling of these techniques to gastrointestinal models, along with further standardization, will further strengthen methodologies for risk assessment.

Intraoperative assessment of surgical margins of oral squamous cell carcinoma using frozen sections: a practical clinicopathological management for recurrences

Background. Local recurrence remains a challenging clinical issue for the treatment of oral squamous cell carcinoma (SCC). We analyzed retrospectively how effective the frozen section technique (FS) was against recurrences of oral SCC. Methods. We screened 343 surgical samples from 236 patients who had oral SCC, carcinoma in situ (CIS), or epithelial dysplasia, and we followed up their clinical outcomes for at least 5 years. Histopathological states of surgical margins were compared between FS and surgical materials in relapse and relapse-free groups, respectively. Results. Among the 236 patients, 191 were classified into the relapse-free group, and 45 into the relapse group. FS was more frequently performed in the relapse-free group (128/191) than in the relapse group (83/152). Histopathologically, moderate dysplasia or CIS (borderline malignancies) and SCC were recognized in 55 samples of the relapse-free group and in 57 of the relapse group. For those surgical margins with borderline malignancies, additional incisions were performed in 38 of the 55 relapse-free cases, which reduced to 20 from the 38 margins with borderline malignancies (47.4% reduction), and in 39 of the 57 relapse cases, which reduced to only 3 of 39 (7.7% reduction). Conclusions. The intraoperative assessment of surgical margins by FS is essential in preventing recurrences of oral mucosal malignancies.

Current views and perspectives on classification of squamous intraepithelial lesions of the head and neck

The current state in the field of classifying oral and laryngeal precursor lesions, as proposed in the WHO 2005 Blue Book is not ideal. The results of various inter-observer studies have shown that the currently used grading systems, with different basic concepts and different terminology, cannot continue to be reliably used in the future. The different etiology of cervical and head and neck precursor lesions requires a classification designed to cater to the specificities of the head and neck region. Trying to harmonize different classifications of the oral and laryngeal precursor lesions, we have proposed four crucial steps to set up a unified classification of squamous intraepithelial lesions (SILs): (a) the classification should contain two grades, low-grade and high-grade lesions and, specifically for the larynx, an additional grade-carcinoma in situ (CIS) which must be separated from high-grade laryngeal SILs; (b) the terminology should be unified; our preference is for the term SIL over squamous intraepithelial neoplasia; (c) all leading morphological criteria for low- and high-grade lesions, as well as for CIS, should be clearly defined; (d) agreement between clinicians and pathologists should be achieved on the most appropriate choice of treatment of different grades of SILs in separate head and neck areas.

Squamous Cell Carcinomas of the Anterior Oral Cavity Are Commonly Associated With Simplex (or Differentiated) Oral Intraepithelial Neoplasia

Introduction: We investigated the occurrence of differentiated oral intraepithelial neoplasia (DOIN) that met the criteria for differentiated intravulvar neoplasia, associated with invasive squamous cell carcinoma (SCC) of the anterior oral cavity, and its clinicopathologic significance. Materials and Methods: Sixty-nine consecutive cases of SCC of the anterior oral cavity were categorized into 2 groups: group A comprised SCC associated with DOIN; Group B consisted of cases associated with classical SCC in situ. Results: Fifty-five cases (80%) were classified as group A, or DOIN lesions, with only 14 (20%) as group B. All cases were associated with invasive SCC, except 2 cases in group B. Squamous epithelium continuous or adjacent to invasive SCC displayed consistent changes in the parabasal and basal layers with (1) cytologic atypia with proliferation of parabasal cells in downward expansion causing reactive proliferation of the basal cell layer in early stage and invading the basal layer in late stage, (2) disordered nuclear/cytoplasmic arrangement, and (3) a “cobblestone” appearance characterized by prominent intercellular spaces and cytoplasmic density involving the entire cell (dyskeratosis) of the parabasal layer. p53 and Ki67 immunostaining revealed linear reactivity mainly in the parabasal layer. Conclusions: DOIN lesions are frequently associated with invasive SCC of anterior oral cavity. Due to the subtle histopathologic changes, DOIN lesions pose potential diagnostic difficulty with differentiation from mild dysplasia or reactive atypia.

[Aero-digestive tract squamous intra-epithelial neoplasia]

Aero-digestive tract squamous intra-epithelial neoplasia is a disease whose genetic and epigenetic features lead to clinical signs and well codified histologic features. This publication aims to review the molecular alterations which have been identified in these lesions, to clarify the clinical manifestations and to discuss the proposed histological classification.

Differentiated dysplasia is a frequent precursor or associated lesion in invasive squamous cell carcinoma of the oral cavity and pharynx

The source of precursor lesions of squamous cell carcinoma (SCC) of the oral cavity and pharynx, their classification, and grading are controversial. In contrast, vulvar and penile cancer precursor lesions are known to be related to human papillomavirus or chronic inflammation and can be described using the vulvar intraepithelial neoplasia (VIN) classification system (VIN 1-3) or as differentiated vulvar intraepithelial neoplasia (dVIN), respectively. Oral and pharyngeal SCC precursor lesions are more etiologically diverse, and the spectrum of lesions may thus be wider. No international consensus exists regarding the histological types of precursor lesions or the significance of individual types. We therefore reviewed resection specimens and preceding biopsies of 155 patients with SCC of the oral cavity and pharynx (excluding tonsils) and identified five basic patterns of SCC-associated or precursor lesions: (1) pleomorphic (22/155), (2) basaloid (5/155), (3) differentiated (63/155), (4) mixed (42/155), and (5) verrucous (12/155). Keratinization was a common but variable feature in differentiated, mixed, and verrucous dysplasia. In 11/155 patients, no precursor lesion could be identified. Progression of isolated differentiated dysplasia (ranging from months to years) was documented in 13/155 (8 %) of patients. Our data suggest that full-thickness epithelial dysplasia of pleomorphic or basaloid type is present in <20 % of oral and pharyngeal SCC, and differentiated dysplasia is a frequent precursor or associated in situ lesion. Failure to recognize differentiated dysplasia results in the underdiagnosis of many patients at risk for invasive carcinoma. These results indicate a need to refine criteria to distinguish differentiated dysplasia from morphologically related lichenoid lesions.

Growth hormone-releasing hormone receptor splice variant 1 is frequently expressed in oral squamous cell carcinomas

The expression of growth hormone-releasing hormone (GHRH) splice variant 1 (SV1) receptor in neoplastic lesions of the oral cavity was assessed. The sensitivity of HaCaT keratinocytes to GHRH analogs was also evaluated. Thirty-three benign precancerous oral lesions and 27 squamous cell carcinomas of the oral cavity were evaluated by immunohistochemistry for SV1 expression. SV1 expression in HaCaT keratinocytes was assessed by western blot. HaCaT proliferation was evaluated by cell counting. Anti-SV1 immunoreactivity was detected in only 9% (three of 33) precancerous lesions (one hyperplasia and two dysplasias), while 44% (12 of 27) carcinomas were positive for SV1 (p<0.002). GHRH(1-29)NH(2) and GHRH agonist JI-38 stimulated HaCaT proliferation in vitro, and this effect was blocked by GHRH antagonists. These results indicate that SV1 expression may be associated with the transition of precancerous lesions to carcinomas of the oral epithelium. GHRH antagonists may be useful for the management of the disease.

Loss of DLC1 is an independent prognostic factor in patients with oral squamous cell carcinoma

Deleted in liver cancer (DLC1), a Rho GTPase-activating protein, was observed to be differentially expressed in oral squamous cell carcinoma in comparison with normal tissues using tissue proteomics. In the current study, we investigated the clinical significance of loss of DLC1 expression in different stages of development of oral squamous cell carcinoma to determine its potential as a biomarker for oral dysplasia and prognosis of oral squamous cell carcinoma. Immunohistochemical analysis of DLC1 expression was carried out in oral squamous cell carcinoma patients (n=214), dysplasia (n=51), hyperplastic squamous mucosa (n=45), and histologically normal oral tissues (n=80), and correlated with clinicopathological parameters and disease prognosis over 91 months for oral squamous cell carcinomas. Loss of DLC1 expression was observed in oral squamous cell carcinoma (64%), oral dysplasia (31%), hyperplastic squamous mucosa (22%), and normal mucosa (16%). Significant loss of DLC1 expression was observed in oral squamous cell carcinomas as compared with dysplasia (P<0.001, odds ratio=3.8, 95% CI=2.0-7.3), suggesting it may be an important event involved in cancer progression. Among oral squamous cell carcinomas, the loss of DLC1 expression was significantly associated with poor prognosis (P=0.021, hazards ratio (HR)=1.8, 95% CI=1.1-2.9). Multivariate analysis revealed loss of DLC1 (P=0.023, HR=2.1, 95% CI=1.2-3.9) and histopathological grade (P=0.015, HR=1.7, 95% CI=1.1-2.7) to be independent predictors for disease-free survival in oral squamous cell carcinoma patients in comparison with known prognostic factors, viz. tumor stage, nodal status, and overall stage. Loss of DLC1 expression emerged as an important biomarker for predicting patients diagnosed with oral dysplasia at high risk of transformation upon future validation in longitudinal studies. Loss of DLC1 expression is a poor prognostic marker for oral squamous cell carcinoma patients.