Argyrophilic proteins of nucleolar organizer regions (AgNORs) in salivary gland mucoepidermoid carcinoma and its relation to histological grade

Roles of Proliferation and Angiogenesis in Locally Aggressive Biologic Behavior of Ameloblastoma versus Ameloblastic Fibroma

(1) Background: The present study was carried out to evaluate the roles of proliferation and angiogenesis in locally aggressive biologic behavior of ameloblastoma versus ameloblastic fibroma; (2) Methods: 30 formalin-fixed paraffin embedded blocks (15 cases of ameloblastoma and 15 cases of ameloblastic fibroma) were used. To evaluate the proliferation, the tissue sections were stained with an AgNORs stain. CD105 was used as an immunohistochemical marker of angiogenesis. Quantitative evaluations of AgNORs were performed. The mean vascular density was evaluated as a measure for CD105 protein expression by using image analyzer computer system; (3) Results: The mean number of AgNORs dots per nucleus was significantly higher in ameloblastoma as compared to ameloblastic fibroma. Additionally, the protein level of CD105 showed positive expression and wide distribution that the mean vascular density was significantly higher in ameloblastoma as compared to ameloblastic fibroma; (4) Conclusion: Quantitative evaluation of the AgNORs stain and the mean vascular density utilizing CD105 protein expression may reflect a higher proliferative activity and a more locally aggressive biologic behavior of ameloblastoma when compared to ameloblastic fibroma, indicating that other factors may be involved in biologic behavior of ameloblastic fibroma.

The role of eukaryotic translation initiation factor 6 in tumors

Eukaryotic translation initiation factor 6 (eIF6) affects the maturation of 60S ribosomal subunits. Found in yeast and mammalian cells, eIF6 is primarily located in the cytoplasm of mammalian cells. Emerging evidence has demonstrated that the dysregulated expression of eIF6 is important in several types of human cancer, including head and neck carcinoma, colorectal cancer, non-small cell lung cancer and ovarian serous adenocarcinoma. However, the molecular mechanisms by which eIF6 functions during tumor formation and progression remain elusive. The present review focuses on recent progress in terms of the mechanisms and functions of eIF6 in human tumorigenesis or cancer cell lines, along with the signal transduction pathways in which this novel translation initiation factor may participate. Oncogenic Ras activates Notch-1 and promotes transcription of eIF6 via a recombining binding protein suppressor of Hairless-dependent mechanism. In addition, overexpression of eIF6 results in aberrant activation of the Wnt/β-catenin signaling pathway. Similarly, overexpressed eIF6 regulates its downstream modulator, cell division control protein 42, which in turn affects oncogenesis. Finally, the potential of eIF6 as a biomarker for diagnosis of cancer is also discussed in the present review.

Argyrophilic nuclear organizer region and p73 expression in head and neck squamous cell carcinomas: Teammates or adversaries?

Context:

Head and neck squamous cell carcinoma (HNSCC) consists of squamous cell carcinomas (SCCs) arising in the upper aerodigestive tract and accounts for 5% of cancers worldwide. In Malaysia, cancers of the nasopharynx, larynx, tongue and oral cavity are among the top twenty most common cancers in men. Argyrophilic nuclear organizer regions (AgNORs) are increased from normal mucosa to premalignant lesions to malignant lesions and have been associated with tumor grade and prognosis of patients. Although p73 is not mutated in human cancers, high levels of p73 expression have been associated with tumor differentiation status and patient prognosis.

Aims:

To investigate the correlation between AgNORs and p73 immunoexpression.

Settings and Design:

Fifty-two formalin-fixed, paraffin-embedded HNSCC cases and ten controls were collected from the Hospital.

Subjects and Methods:

Tissue blocks were sectioned, dewaxed and rehydrated before silver nitrate staining to determine the AgNOR count and immunohistochemical staining to determine the p73 expression. Adopting the scoring system used by Chen et al. for p73 staining, the proportion of positively stained cells in the whole epithelial layer was determined. Staining was considered positive if >10% of epithelial cells were stained.

Statistical Analysis Used:

Spearman's correlation coefficient was calculated using SPSS 18 software to determine the relationship between the p73 score against tumor differentiation, mean AgNOR counts and tumor grade and between the mean AgNOR count and p73 score.

Results:

Positive results were found in the immunoexpression of p73. Positive results were seen with the staining of AgNOR; however, in comparison with the entire sample size, a significant correlation between mean AgNOR count and p73 immunohistochemical expression was not obtained.

Conclusions:

AgNOR count showed a linear and decreasing trend as the p73 score increases. This correlation was statistically insignificant.

Apoptosis and expression of argyrophilic nucleolus organizer regions in epithelial neoplasms of the larynx

Introduction

Occurrence of apoptosis and expression of proliferative markers are powerful tools to establish a prognosis in the follow-up of cancer.

Objective

To evaluate the growth fraction in papillomas and laryngeal squamous cell carcinomas with three degrees of differentiation through apoptosis and the expression of nucleolus organizer regions.

Methods

Retrospective study from which paraffin material was submitted to microtomy and hematoxylin–eosin and silver staining. Stained slides were used to quantify the apoptotic index and the number of nucleolus organizer regions by morphometry.

Results

Apoptosis was significantly more frequent in well differentiated carcinomas and in papillomas, and a higher growth fraction of expressed nucleolus organizer regions and cells that expressed a greater than average number of nucleolus organizer regions were more frequently noted in undifferentiated carcinomas.

Conclusions

Thus, it was possible to verify that a high apoptotic index was associated with a lower chance of tumor differentiation in carcinomas, while a greater number of total nucleolus organizer regions, cells expressing nucleolus organizer regions above average and a higher growth fraction were associated with greater likelihood of abnormal cell proliferation and increased tumor differentiation.

The AgNORs count in predicting long-term survival in serous ovarian cancer

INTRODUCTION

The value of argyrophilic nucleolar organizer regions (AgNORs) to predict survival in patients with ovarian cancer has not been clearly explained yet. The aim of study was to assess the value of analysis of the mean number of AgNORs per nucleus (mAgNOR) and mean percentage of nuclei with five or more AgNORs per nucleus (pAgNOR) in the prediction of disease-free survival (DFS) and overall survival (OS) in patients with serous ovarian cancer.

MATERIAL AND METHODS

The study examined 52 patients treated for serous ovarian cancer with a follow-up period of 2-143 months. After silver staining paraffin specimens from primary surgery, mAgNOR and pAgNOR in cancer cells were counted and analyzed. Age, grading, radicality of surgery and FIGO staging were analyzed as covariates.

RESULTS

Mean mAgNOR equaled 4.4 ±0.9 and pAgNOR equaled 42.2 ±20.8%. Both mAgNOR and pAgNOR were the lowest in G1 tumors. The mAgNOR and pAgNOR were lower in stage I than stage IV cancers. The DFS and OS rates were respectively 15.4% and 21.2%. In univariate analysis FIGO staging, grading, and pAgNOR were associated with worse prognosis, while radicality of surgery remained a significant protective factor in terms of DFS. Higher FIGO staging and older age worsened OS. In multivariate analysis FIGO staging remained significantly associated with both DFS (HR 1.98; 95% CI 1.05-3.71) and OS (HR 1.76; 95% CI 1.00-3.10), while age affected OS rates (HR 1.78; 95% CI 1.04-2.95).

CONCLUSIONS

mAgNOR and pAgNOR are useful markers of cellular kinetics. Prospective studies in larger populations are needed to confirm these results in terms of AgNORs' effects on survival.

Nucleolar organizer regions in oral squamous cell carcinoma

BACKGROUND AND AIMS

Several diagnostic methods are being employed to detect benign and malignant lesions, one of which is silver nitrate staining for organizer regions. The number of nucleolar organizing regions (NORs) can be used to show the degree of cell activity or metabolism in pathologic lesions. This study was designed to evaluate NORs as determi-nants of precancerous and squamous cell carcinoma.

MATERIALS AND METHODS

A silver colloid technique was applied on paraffin sections of 40 cases of oral squamous cell carcinoma and 25 cases of precancerous lesions; 15 specimens of normal epithelium were selected for the control group. After staining with silver nitrate, argyrophilic nucleolar organizer regions (AgNORs) were counted in 100 epithelial cells in three groups with the use of an oil immersion and ×1000 objective lens. One-way ANOVA and a post hoc Tukey test were used for statistical analysis.

RESULTS

The mean numbers and standard deviations of AgNORs were 1.58 ± 0.76 in normal epithelium, 2.1 ± 1.05 in pre-cancerous lesions and 2.43 ±1.33 in squamous cell carcinoma (SCC). There were statistically significant differences in Ag-NORs numbers between the groups (P<0.001) and significant differences in precancerous lesions between dysplastic and non-dysplastic epithelia (P<0.001). The mean AgNORs count per nucleus increased from healthy epithelium to precancer-ous lesion to SCC.

CONCLUSION

This study suggests that the silver staining technique for the detection of NORs (AgNOR) can be used to distinguish precancerous lesions and benign and malignant lesions.

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.