AgNOR cut-point to distinguish mild and moderate epithelial dysplasia

A Comparative Study of Morphometric Analysis of Nucleolar Organizer Regions in Oral Leukoplakia and Oral Squamous Cell Carcinoma and Significance of AgNOR as a Diagnostic Tool

Background Silver stainable nucleolar organizer regions (AgNORs) have proven to exhibit utmost importance due to their higher occurrence in the nucleus especially in malignant cells than in normal. Thus, they assist in the examination of nucleolar structures and variations in nucleolar activity. Aim Quantitative and qualitative analysis in relation to the number and area of AgNOR in tissue sections of the normal oral mucosa (NOM), oral leukoplakia (OL), and oral squamous cell carcinoma (OSCC) was the main aim of the study. Materials & method A total of 50 cases comprising 20 OL with dysplasia, 20 OSCC cases, and 10 samples of normal oral mucosa were taken. Silver nitrate (Sol A) & gelatin (Sol B) solutions were freshly prepared for staining the lesional slides. Results The mean value of nuclear profile area (A Nuc) was comparatively higher in oral leukoplakia i.e. 41.97 and in oral squamous cell carcinoma i.e. 62.36 in comparison to the control group where it was 36.19. The mean value of a single AgNOR profile area per nucleus (A NOR) was found to be comparatively lower in both study groups i.e. oral leukoplakia (2.76) and oral squamous cell carcinoma (1.61) in comparison to the control group (3.45) . The mean value of total AgNOR profile area per nucleus (TA NOR) and the number of profiles of AgNORs per nucleus (n NOR) were found higher in both study groups (oral leukoplakia and oral squamous cell carcinoma) as compared to normal oral mucosa of the control group. However, the findings of all four parameters of morphometric analysis were found to be significantly associated with disorder of oral mucosa i.e. cases of oral leukoplakia and oral squamous cell carcinoma (P value <0.01). Conclusion It can thus be suggested that the mean AgNOR count displayed a higher value in OSCC. Hence, the number of AgNORs in nuclei increases as epithelial cells undergo malignant transformation which is designated that mean AgNOR count may contribute to establishing the prognosis of a lesion.

Quantitative and qualitative assessment of argyrophilic nucleolar organizer regions in normal, premalignant and malignant oral lesions

Aim

The aim of the study was to assess the cell proliferation and biologic aggressiveness of the lesions by evaluating the significance of number and dispersal pattern of Argyrophillic Nucleolar organizing Regions (AgNORs) using silver colloid technique in normal mucosa, premalignant and malignant lesions.

Settings and Design

In-vitro study, lab setting.

Methods and Material

The study sample consisted of five groups each with a sample size of 10 and a control group. Group I (Control), Group II (Oral Submucous Fibrosis - Mild dysplasia), Group III (Oral Submucous Fibrosis - Moderate dysplasia), Group IV (Leukoplakia - Mild dysplasia), Group V (Leukoplakia - Moderate dysplasia) and Group VI (Squamous cell carcinoma). Two sections were cut, of which one was stained with H/E stain for histopathological analysis and the second one with Silver nitrate for AgNOR counting and grading. The data obtained were analyzed both qualitatively and qualititavely.

Statistical Analysis Used

Student's Unpaired T test and One- way ANOVA.

Results

The Mean AgNOR count increased in the following ascending order: i.e OSMF with mild dysplasia, leukoplakia with mild dysplasia, OSMF with moderate dysplasia, leukoplakia with moderate dysplasia and squamous cell carcinoma. Qualititatively, Type II AgNOR pattern was found to be the predominant one in all the samples. Type III AgNOR pattern was found to be increasing with the increase in the grade of dysplasia.

Conclusions

AgNOR quantity is proportional to the proliferative activity of the cell and does not necessarily always indicate malignancy. It is the qualitative characteristics of AgNOR that help to differentiate the premalignant and malignant lesions.

Malignant transformation of oral submucous fibrosis: overview of histopathological aspects

Oral submucous fibrosis (OSF), first described in 1952, is a potentially malignant disorder associated with betel quid and areca nut chewing, mostly prevalent in the population of the Indian subcontinent and South East Asia. Malignant transformation of OSF to squamous cell carcinoma (SCC) has been estimated to be between 2% and 8%. Our study aimed to review the histopathologic changes that contribute to the understanding of the malignant transformation of OSF. Changes in epithelial thickness and dysplasia characterized by micronuclei, altered AgNOR counts and distribution, keratin protein alteration, and alteration of P63 and E-cadherin characterize the epithelial changes during the transformation of OSF to SCC. Common mechanisms have been proposed to be involved in OSF and SCC, through collagen maturation and their interaction with myofibroblasts and mast cells. Fibrosis-driven vascular constriction that results in epithelial hypoxia has also been proposed as an important mechanism for the malignant transformation of OSF. However, reassessment of the classical view is required, because with demonstration of large blood vasculature in the connective tissue stroma of OSF, the hypothesis associated with tissue hypoxia-induced malignant transformation of OSF can be questioned.

Silver binding nucleolar organizer regions dots in oral leukoplakia with epithelial dysplasia and oral squamous cell carcinoma: an in vivo study

Silver binding nucleolar organizer regions (AgNOR) in normal oral mucosa (NOM), oral leukoplakia with epithelial dysplasia (ED), and oral squamous cell carcinoma (OSCC) were studied. The mean AgNOR count per nucleus increased from NOM to ED to OSCC. Tissue showing ED in oral leukoplakia and OSCC cases showed higher counts, wider scatter, and smaller size of AgNOR dots in the nuclei. The study seems to suggest that time method has some potential in distinguishing between NOM and oral leukoplakia with ED and OSCC. Studies of larger numbers are needed to arrive at more substantial conclusions.

Evaluation of the efficacy of AgNOR as a proliferative marker in oral leukoplakia: A morphometric analysis

Background:

Silver stainable nucleolar organizer regions (AgNORs) are replicatory markers which may have a place in objectively characterizing dysplasia.

Materials and Methods:

A study of various morphometric parameters related to AgNORs was performed in basal and parabasal layers of normal human oral epithelium, nondysplastic leukoplakia, and dysplastic leukoplakia employing photomicrographs of silver stained paraffin embedded sections using image analysis, to assess the usefulness of these parameters in distinguishing dysplastic leukoplakia from nondysplastic oral leukoplakia.

Results:

Out of various mean AgNOR related parameters, AgNOR count, area, perimeter, and proportion were found to be higher in dysplastic leukoplakia as compared to nondysplastic leukoplakia. On statistical analysis, AgNOR count showed statistically significant differentiation between dysplastic and nondysplastic leukoplakia. While other parameters can distinguish normal oral epithelium from dysplastic and nondysplastic leukoplakia.

Conclusion:

To conclude, the AgNOR count is the most appropriate marker to differentiate between dysplastic and nondysplastic leukoplakia.

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.

Histologic grading and nucleolar organizer regions in oral squamous cell carcinomas

Objective

The purposes of this study were to histologically assess different types of oral squamous cell carcinoma and the silver-binding nucleolar organizer region (AgNOR) morphology in neoplastic cells, as well as to quantify the number of AgNORs in each type of carcinoma in order to relate AgNOR count and histologic grading.

Material and Methods

Twenty-eight cases of oral squamous cell carcinoma were divided into 4 groups, namely well-differentiated, moderately differentiated, poorly differentiated, and undifferentiated. For NOR study, 3-µm-thick sections were stained with 50% aqueous silver nitrate solution. The predominant microscopic pattern of NORs was determined. Quantitative analyses of NORs were obtained of all cells present on each histological field using a 0.025 mm² eyepiece graticule. Different histological fields were analyzed until the total number of NORs was 120 cells for each tumor. Kruskall-Wallis test was applied to compare the groups of sample data at a significance level of p=0.05.

Results

The mean number of AgNORs per nucleus was 3.20 for the well-differentiated group, 5.33 for the moderately differentiated one, 8.27 for the poorly differentiated one, and 10.08 for the undifferentiated one. AgNOR count was significantly different (p<0.05) among all of the studied groups.

Conclusion

AgNOR staining technique seems to be a useful diagnostic tool since differences in AgNOR numeric values can be identified in the different types of oral squamous cell carcinoma. This technique is easy to handle and inexpensive, thus justifying its large use in histopathology.

Need for an Ethical Framework for Testing for Systemic Diseases in Dental Clinics

Testing for systemic diseases in dental clinics is a potentially attractive avenue for oral health professionals and may be viewed as an opportunity to increase professional reach, expand practice, and improve financial returns. However, several ethical questions arise that must be addressed before such activities are adopted. (1) What should be the level of training dentists must acquire to deal with challenges associated with testing? (2) How well are dental practices aware of and compliant with the Health Insurance Portability and Accountability Act and procedures related to informed consent? (3) What is the evidence regarding acceptability and effectiveness of testing? (4) What should be the acceptable standard of practice for conduct of invasive and noninvasive tests? (5) What is the boundary delineating "testing" and "reporting" vis-à-vis counseling? (6) What is the value of testing without counseling? (7) What assurances need to be in place to ensure voluntariness of testing? (8) How would data from testing be used in "research," especially with the growth of practice based research networks? and (9) Does the American Dental Association Code of Ethics need to incorporate guidance for practicing dentists? We discuss how ethical principles can be used to develop a framework of guidelines for potential testing for systemic diseases in dental clinics..

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.