Salivary gland tumours studied by means of the AgNOR technique

Argyrophilic staining of nucleolar organizer region count and morphometry in benign and malignant melanocytic lesions

Differentiation between malignant melanomas (MMs) and benign nevi based on histologic features can sometimes be difficult. This study evaluated the diagnostic effectiveness of argyrophilic staining of nucleolar organizer regions (AgNORs) in separating benign nevi from MMs by assessing 27 compound nevi (CN), 20 dysplastic nevi (DN), 10 Spitz nevi (SN), and 24 MMs. Both AgNOR count and morphology variables were measured from the superficial, middle, and deep zones of the lesions using video image analysis. Malignant melanomas had a significantly greater AgNOR number per nucleus, mean AgNOR area per nucleus, and variation in AgNOR area per nucleus compared with all types of benign nevi (p < 0.05). In multivariate discriminant analysis using a combination of four AgNOR counts and morphometric parameters, all CN and DN, 8 of 10 SN, and 23 of 24 MMs could be correctly classified as benign or malignant. The results suggest that both AgNOR count and morphology help to separate benign and malignant melanocytic lesions and that the combination of both sets of parameters improves their discriminating ability.

Age-related changes in proliferative markers in labial salivary glands: a study of argyrophilic nucleolar organizer regions (AgNORs) and Ki-67

The aim of the present study was to examine age-related changes in the proliferative capacity of acinar and ductal cells in labial salivary glands of healthy subjects as reflected by AgNOR and Ki-67 parameters. The study was conducted on 24 postmortem samples of labial salivary glands free from salivary gland tumors/diseases. Samples were equally divided into three age groups: young (mean age 17 yr), adult (mean age 38 yr) and old (mean age 84 yr). The number of profiles of AgNOR (nNOR) and AgNOR profile area per nucleus (TVNOR) were histomorphometrically assessed by CUE-3 automatic image analyzer on 30 nuclei of acinar and intercalated ductal cells in each age group. The percentage of Ki-67 positively stained acinar and ductal cells was evaluated histomorphometrically. Statistical analysis was carried out by one-way ANOVA and Kruskal-Wallis tests. In the acinar cells, nNOR increased significantly with aging (p<0.00001), while TVNOR did not change significantly. In the ductal cells, both nNOR and TVNOR increased significantly (p<0.00001) with a relatively higher increase in TVNOR. Since only isolated acinar and ductal cells demonstrating Ki-67 positive nuclei were found in the different age groups, the overall proliferation index was estimated to be 0%. Thus, it is suggested that age-related changes in AgNOR parameters could reflect changes in the metabolic cell activity rather than changes in their proliferative capacity. In this context, AgNOR results are in accordance with the histomorphometric and physiologic age-related changes occurring in labial salivary glands.

[Cell proliferation in salivary gland tumors]

Previous studies on cell proliferation in salivary gland tumors have shown the utility of immunostain with MIB1 in the differential diagnosis and prognosis of these neoplasms. We have carried out a study of 39 salivary gland tumors (17 benign), from different histological lineages. The immunocytochemical method used was the streptavidin--biotin--peroxidase complex which used the MIB1 monoclonal antibody. Benign tumors showed a low cell proliferation rates, below 5% with an overall average of 1.9%. The malignant tumors presented higher rates, with a middle value of 17.85%. Epidermoid carcinomas had the higher cell proliferation rates, with an average of 43%. In adenoid cystic carcinomas, we have observed that proliferation was greater at the peripheral level of tumor nests and cell surrounding the cystic structures. Neoplasms of low grade of malignancy presented lower cell proliferation rates. The MIB1 immunostain allowed to reach a differential diagnosis between pleomorphic adenoma and adenoid cystic carcinoma, specially in those cases in which there could be any doubt.

Evaluation of the nucleolar organizer region associated proteins in exfoliative cytology of normal buccal mucosa. Effect of smoking

An evaluation of cellular alterations in the smoker's oral mucosal cells was performed. The Exfoliative Cytology technique was applied and the cytological smears stained with silver for the enumeration of Argyrophilic nucleolar organizer regions (AgNORs). Cytological smears were collected from two anatomic sites: floor of the mouth and tongue border, in both groups, smokers and non smokers, with a purpose of correlating the smoking habit to possible cellular alterations. The enumeration of the AgNORs showed that the average number of AgNORs is higher in smokers. There is a significant difference (P=0.0001) between smears from the floor of the mouth and from tongue border in the smoking group. In this study, no correlation between number of cigarettes, age and gender was found, but the results suggest that there might be a correlation between the smoking habit and an increased rate of cellular proliferation in the oral mucosal cells.

Morphometric analysis of argyrophilic nucleolar organizer regions (AgNORs) in nasopharyngeal carcinoma

BACKGROUND

Nucleolar organizer regions (NORs), which are loops of DNA containing ribosomal RNA genes, have been shown to correlate with cell proliferation and malignant transformation. Conventional eyeball measurement of silver staining NORs (AgNORs) is time-consuming and subject to error. The diagnostic value of AgNOR area in nasopharyngeal carcinoma (NPC) by computer-assisted morphometric analysis is evaluated.

METHODS

Silver-staining of NORs was applied to 23 paraffin sections of NPC containing both normal squamous epithelial and malignant cells. Various parameters of the AgNORs of these two cell types were analyzed by a computer-assisted image analysis system and then compared.

RESULTS

The mean AgNOR area, AgNOR/nuclear area ratio, and AgNOR area/count ratio of malignant tumors were statistically significantly higher than those for the normal epithelium. There was no significant difference in the AgNOR counts between the two cell types.

CONCLUSIONS

Computer-assisted morphometric analysis of AgNOR is an objective and reliable assessment method applicable to paraffin sections of NPC. The AgNOR area and its derivatives may aid in the diagnosis of NPC.

Mucoepidermoid carcinoma of salivary glands in children and adolescents: assessment of proliferation markers

Malignant neoplasms represent one-third of all pediatric salivary gland tumors. Mucoepidermoid carcinoma (MEC) composes 51% of malignant tumors and 16% of all salivary gland neoplasms in pediatrics. Prognostic factors in MEC in pediatric patients have not been well defined. Histopathologic features, clinical outcomes and proliferation markers in 26 pediatric patients (median age 11 years; 19F:7M) with salivary gland MECs were evaluated retrospectively. MEC histocytologic grading used a three-tiered system. Proliferation was assessed by determining the percentage of tumor cells immunoreactive for PCNA and Ki-67. Tumor site was 16 parotid, eight submandibular, one base of tongue and one maxillary lip. Median tumor size was 2.5 cm (range 1.5-5 cm). MEC grade was nine low grade (LG), 15 intermediate grade (IG) and two high grade (HG). Metastatic disease and capsular invasion occurred in five cases, while perineural invasion was noted in three cases. Mean percentage of tumor cells immunoreactive for proliferation markers is as follows: PCNA: LG 9%, IG 17%, HG 32%; and Ki-67: LG 7%, IG 12%, HG 26%. Treatment was surgical in 21 cases, and surgery with chemotherapy and radiotherapy in five cases. Two patients with high grade MECs died of disease (21, 44 months). Twenty-four patients had no evidence of disease at a median follow-up of 104 months (range 30-298 months). MECs were second malignancies in two children with prior radiotherapy and chemotherapy for leukemia and histiocytosis. Low and intermediate grade salivary gland MECS in a pediatric population may have a favorable outcome when compared with high grade MECs. Proliferation markers appear to be linked to histocytologic MEC grade and may provide information regarding biologic behavior of salivary gland MECs in children and adolescents.

Age-related changes in cellular activity in human submandibular glands as evaluated by argyrophilic nucleolar organizer regions

OBJECTIVE

To examine the age-related changes in cellular activity of epithelial components of human submandibular glands, evaluated on the basis of argyrophilic nucleolar organizer regions (AgNORs).

DESIGN

Epithelial components of human submandibular glands were divided into serous acinar cells, mucous acinar cells, intercalated duct cells, striated duct cells, and interlobular duct cells. The mean AgNOR number of each cell type was compared among six age groups.

SETTING

The study was conducted at the Department of Oral Pathology, Tohoku University School of Dentistry, Japan.

SUBJECTS

Necropsy specimens from 66 males and 57 females 1 to 97 years old.

RESULTS

In all cell types except for intercalated duct cells, the mean AgNOR number was lowest in the 0-14 year-old group and highest in the 15-29 year-old group. The value then gradually decreased with advancing age and ultimately reached a similar level to that in the 0-14 year-old group. In intercalated duct cells, the mean AgNOR number did not differ significantly between any age group. There were no significant sex-related differences.

CONCLUSIONS

The cellular activity of almost all components of human submandibular glands rises in adolescence and young adulthood and then decreases with aging. These results suggest that intercalated duct cells are capable of not only proliferation but also division into other components; these cells may thus compensate for the reduced activity of other components in elderly subjects.

Argyrophilic nucleolar organizer regions in cells of thymoma and thymic carcinoma: correlation with DNA ploidy and clinicopathologic characteristics

STUDY OBJECTIVES

To evaluate the usefulness of argyrophilic nucleolar organizer region (AgNOR) counting and flow cytometric DNA analysis in the differential diagnosis of thymoma and thymic carcinoma, as well as in the differences among various stages and histologic subtypes of these tumors.

DESIGN AND INTERVENTIONS

Paraffin-embedded blocks of 64 thymic epithelial tumors (20 noninvasive thymomas, 34 invasive thymomas, and 10 thymic carcinomas) were studied by AgNOR counting and flow cytometric DNA analysis. The thymomas were histologically classified as medullary, cortical, or mixed subtype.

MEASUREMENTS AND RESULTS

Invasive thymomas had more AgNORs (-/+ SD) than noninvasive thymomas (7.93+/-2.90 vs 5.97+/-1.77; p < 0.01). The number of AgNORs of thymoma increased progressively with advances in stage (p < 0.01). Cortical thymomas had the highest number of AgNORs among the three subtypes (p < 0.05). Patients with thymoma who presented with myasthenia gravis also had a higher number of AgNORs (8.30+/-3.12 vs 6.50+/-2.03; p < 0.01). The AgNOR number did not correlate with the DNA ploidy of all specimens.

CONCLUSIONS

AgNOR counting is useful in differentiating between invasive and noninvasive thymomas, and in predicting the stage of thymomas. A greater number of AgNORs was observed in patients with cortical thymoma and in those who presented with myasthenia gravis.

The evaluation of salivary gland tumours using proliferating cell nuclear antigen

In order to assess its discriminating and prognostic value, we studied the immunoreactivity for proliferating cell nuclear antigen (PCNA) in tissue from 52 human salivary gland tumours using the murine monoclonal antibody PC10. The PCNA percentage count, namely, the average number of positive nuclei counted per 100 randomly selected tumour cells was recorded for each tumour. Anaplastic carcinoma was used as a positive control and histologically 'normal' salivary gland and tonsil served as a negative control. A PCNA count of 30 per cent was postulated to predict malignancy within a given salivary gland tumour i.e. a PCNA count of 30 per cent or above would indicate malignant potential. This gave a sensitivity of 96.9 per cent and a specificity of 95.2 per cent and a positive predictive value of determining malignancy of 96.8 per cent. We conclude that PCNA immunoreactivity is useful in discriminating between benign and malignant salivary gland tumours and that it may have prognostic value in this diverse group of neoplasms.

p53 and bcl-2 expression and argyrophilic nucleolar organizer regions in patients with malignant maxillary sinus tumours

To investigate the relation between the clinicopathological findings, and the survival of patients with malignant tumours of the maxillary sinus, and the tumour's biological parameters, we examined the expression of p53 and bcl-2 and the number of silver-stainable nucleolar organizer regions (AgNORs) in 23 paraffin-embedded specimens from primary tumours. Fifteen of 23 (65 per cent) maxillary tumours expressed p53 and two of 23 (nine per cent) tumours expressed the bcl-2 gene product. The mean number of AgNORs per nucleus was 5.2 +/- 2.4. There was no relationship between the expression of p53 or bcl-2 and the patient's clinical course. In contrast, there was a statistically significant difference in the survival of patients with a high (> 6) number of AgNORs and patients with a low (< 6) number of AgNORs. These data suggest that the number of AgNORs may be useful in evaluating the prognosis of patients with malignant maxillary sinus tumours.

Nucleolar organizer regions (AgNORs) in odontogenic cysts and ameloblastomas

The aim of this study was to determine whether nucleolar organizer regions (AgNORs) may be of value in distinguishing various odontogenic cysts from the unicystic ameloblastoma. Histological sections were prepared from fifteen cases each of odontogenic keratocyst, residual cyst, dentigerous cyst, unicystic ameloblastoma and conventional ameloblastoma. In each case intra-nuclear AgNOR dots were counted in 100 consecutive basal nuclei. Statistical comparison of the least squares means showed that those areas of unicystic ameloblastomas lined by characteristic epithelium had a significantly lower AgNOR count than the other groups (P < 0.05). The dentigerous cysts had significantly higher AgNOR counts than the residual cysts and unicystic ameloblastomas (P < 0.05). These differences may or may not be indicative of variations in metabolic, proliferative or transcriptional activity. We conclude that AgNOR counts are not of diagnostic significance and cannot be used to distinguish the various odontogenic cysts from one another nor from the unicystic ameloblastoma.

Image analysis for quantification of nucleolar organizer regions in basal cell carcinoma and seborrheic keratosis

BACKGROUND/AIMS

Nucleolar organizer regions (NORs) have recently attracted much attention because of claims that their frequency within nuclei is significantly higher in malignant cells than in normal, reactive, or benign neoplastic cells. The purpose of this paper is to analyze a method allowing selection of the best morphometric criterion for quantifying AgNORs (Silver stained Nucleolar organizer Regions) under conventional observation conditions, by light microscopy.

METHODS

The various parameters including NORs counting in cutaneous tumors using image analysis system were studied.

RESULTS

There were significant differences in mean numbers of AgNORs per nucleus, mean ratio of AgNORs area per nucleus area, mean ratio of greatest AgNORs area per nucleus area, mean nucleus area per a AgNOR, and CV (Coefficient of Variation) of AgNORs area between basal cell carcinoma and seborrheic keratosis.

CONCLUSION

Study of AgNORs using the image analysis system is a useful tool for diagnosis of cutaneous tumors.

Correlation of Ag-NOR protein measurements with prognosis in canine transmissible venereal tumour

Ten canine transmissible venereal tumour (TVT) cases were studied by digital image analysis quantification on sections stained with silver to demonstrate nucleolar organizer regions (Ag-NORs). In each animal, 100 neoplastic cells were randomly selected for evaluation. The following parameters were measured or calculated: area of nucleus, area of Ag-NOR dot, the mean number of Ag-NOR dots per nucleus, the mean area of Ag-NOR dots per nucleus and the ratio of mean nuclear dot area to nuclear area. All 10 cases were treated with vincristine at a dose of 0.6 mg/m2 intravenously once a week. Two, which showed malignant characteristics (i.e. uncontrolled growth, local invasion or metastasis), did not respond to multiple (12) treatments and had a fatal outcome. Of the remaining eight cases, seven responded to two to six treatments and one required 12 treatments. The average number of Ag-NORs per nucleus and the area of Ag-NORs per nucleus were lower in the seven cases that responded to two to six treatments than in the other three cases, but the difference was not significant. However, there was a significant difference in the ratios of Ag-NOR area to nuclear area between the two groups of cases. Thus, poor prognosis was (1) possibly correlated with an increase in the mean number of Ag-NORs per nucleus and an increase in the mean area of Ag-NORs per nucleus, and (2) definitely correlated with an increase in the mean ratio of Ag-NOR area to nuclear area.

Histocytologic grading of mucoepidermoid carcinoma of major salivary glands in prognosis and survival: a clinicopathologic and flow cytometric investigation

BACKGROUND

Controversy exists regarding the role of a 3-tiered grading system for mucoepidermoid carcinoma (MEC) of salivary glands in prognosis and survival. This retrospective investigation evaluated a 3-tiered grading system modified from Healey by Batsakis and Luna and compared various clinical, pathologic, and flow cytometric parameters and overall survival among MECs of differing grades.

METHODS

Forty-eight patients with 7 low-grade (LG), 23 intermediate-grade (IG), and 18 high-grade (HG) MECs of parotid (n = 43) and submandibular (n = 5) glands were studied. Data were analyzed using categorical statistics (Wilcoxon, Kruskal-Wallis and Chi-squared tests where appropriate).

RESULTS

Mean ages were 42 years for patients with LG tumors; 47 years, IG; and 59 years, HG (p = 0.02). Gender ratio (p < 0.001) changed from female predominance in LG (6 F:1 M) and IG (2.1 F:1 M) to male predominance in HG (3.5 M:1 F). Mean tumor stage was 1.4 LG, 2.4 IG, and 3.6 HG (p < 0.005). Tumor size increased from 2.1 cm for LG to 3.8 cm for HG (p = 0.01). Margins were involved by tumor in 0% LG, 44% IG, and 61% HG (p < 0.001). Lymph node involvement was 0% LG, 22% IG, and 72% HG (p < 0.001). DNA aneuploidy (DNA index < 0.9 or > 1.1) was present in 0% LG, 13% IG, and 28% HG (p = 0.05). Proliferative fraction (S + G2M) was 5% LG, 7% IG, and 13% HG (p = 0.008). Radiotherapy was administered in 14% LG, 35% IG, and 61% HG (p = 0.03). Recurrences (local and/or metastatic) occurred in 0% LG, 39% IG, and 61% HG (p = 0.009). Survival was decreased significantly (p < 0.0001) with increasing tumor grade (100% LG, 70% IG, and 22% HG).

CONCLUSION

Histologic grading of mucoepidermoid carcinomas of major salivary glands, using the modified Healey 3-tiered system, correlates well with clinical, pathologic, and flow cytometric factors which influence the prognosis and overall survival in affected individuals.

Silver-binding nucleolar organizing regions: a study of oral leukoplakia and squamous cell carcinoma

Silver-binding nucleolar organizing regions (AgNORs) in normal oral buccal mucosa epithelium, oral leukoplakia, and oral squamous cell carcinoma (SCC) were studied. The mean AgNOR count per nucleus increased from healthy mucosa to leukoplakia to SCC. Tissues showing dysplasia in leukoplakia and SCC cases showed higher counts, wider scatter, and smaller size of AgNOR dots in the nuclei. The study seems to suggest that this method has some potential in distinguishing between dysplastic and nondysplastic leukoplakia. Studies of larger numbers are needed to arrive at more substantial conclusions.

Nucleolar organizer regions in follicular tumors of the thyroid

BACKGROUND

Nucleolar organizer regions (NORs) are loops of ribosomal DNA that occur in nucleoli and that transcribe to ribosomal RNA. NORs have been identified by means of the Ag-NOR technique in routinely processed tissues, and were found to be of discriminative value between some types of benign and malignant lesions.

METHODS

Follicular lesions of the thyroid (17 adenomas and 25 carcinomas) were examined. Ten normal thyroids served as the control group. All slides were stained by the Ag-NOR technique and the number of Ag-NOR dots were counted in 50 randomly selected cells. The mean number of Ag-NORs was calculated for each case. Data were statistically analyzed by the Student's unpaired t test.

RESULTS

The mean Ag-NOR counts were statistically higher in follicular carcinomas as compared to either follicular adenomas or the normal thyroid. Higher Ag-NOR counts were found in the more aggressively behaving tumors.

CONCLUSIONS

It is suggested that the Ag-NOR technique could be of use as an adjunct to diagnostic histopathology and as an indicator of biologic behavior in follicular tumors of the thyroid.

Prognostic value of argyrophilic nucleolar organizer regions (AgNOR) count in adenoid cystic carcinoma of salivary glands

A retrospective study was performed on 34 patients with adenoid cystic carcinoma (ACC) to see if quantification of argyrophilic nucleolar organizer regions (AgNOR) was correlated with their prognosis. Mean follow-up period was 113 months. According to detailed clinical data that included tumor recurrences, metastases and patient survival conditions, two groups were classified. Group 1 consisted of 20 live patients without metastases, of whom 16 were free of disease, while group 2 comprised 14 patients with metastases among whom 12 died of tumor. The silver staining technique was applied to paraffin embedded specimens. In each case, 300 nuclei were randomly examined and the mean AgNOR per nucleus was calculated. All patients from group 2 had mean AgNOR counts greater than 4, whereas 65% of patients from group 1 had mean AgNOR counts less than 4. In addition, statistical analysis showed that the pooled mean AgNOR count in group 2 was significantly higher than in group 1 (P < 0.01). The present results suggest that silver staining technique promises to be a useful supplementary method for prognostic evaluation of salivary ACC, and may be performed before planning the treatment.

Evaluation of malignant grade of salivary gland tumors: studies by cytofluorometric nuclear DNA analysis, histochemistry for nucleolar organizer regions and immunohistochemistry for p53

Investigations were carried out in 109 surgically resected salivary gland tumors, 46 adenomas and 63 carcinomas for nuclear DNA content by cytofluorometry, nucleolar organizer regions (AgNOR) by histochemistry and nuclear p53 accumulation by immunohistochemistry. The mean nuclear DNA content and the incidence of aneuploidy as well as the mean number of the AgNOR in carcinomas were significantly higher than those in adenomas. In the DNA histogram pattern, the aneuploidy frequently appeared in high grade carcinoma groups (adenocarcinoma, salivary duct carcinoma, carcinoma in pleomorphic adenoma and oncocytic carcinoma). Immunohistochemical nuclear p53 accumulation was observed in 15 tumors, of which ten showed DNA aneuploidy. In high grade carcinomas, DNA aneuploidy was closely related to p53 immunoreactivity. This study revealed that combined cytofluorometric nuclear DNA analysis, histochemical AgNOR count and immunoreactivity for p53 might be quite useful for evaluating the malignant grade of salivary gland tumors.

Comparing flow cytometric analysis and nucleolar organizer region enumeration in archival oral premalignant lesions

Flow cytometric analysis (FCA) and silver colloidal nucleolar organizer region-associated protein staining (AgNOR) have been used individually in assessing the histopathologic nature of various human tumors. However, few researchers have investigated the relationship between the two techniques in a single series. In a retrospective study, we examined 36 premalignant lesions of the oral cavity by FCA and AgNOR on formalin-fixed, paraffin-embedded tissue submitted to the University of Tennessee, Memphis, oral pathology laboratory. Three categories of epithelial dysplasia were represented (9 mild, 9 moderate, 6 severe), as well as four epithelial hyperplasias without dysplasia, three squamous cell carcinomas, and five fibrous nodules as controls. Parameters recorded for each case included age, race, gender, site, light microscopic diagnosis (LMD), DNA index (DI), total proliferative index (TPI), S-phase (S), range of nucleolar organizer regions (RNOR), and mean number of nucleolar organizer regions (MNOR). The average maximum nucleolar organizer region count (AMXNOR) for each LMD category was also calculated. The objective of the study was to determine if FCA or AgNOR aided in the subjective LMD of oral premalignant lesions and if the parameters recorded for the specimens exhibited any positive correlation. The FCA results indicated an abnormal DI in 6 of the 24 dysplastic lesions. A positive partial correlation was seen between DI and MNOR (r = 0.434; P < 0.012) and TPI and S (r = 0.774; P < 0.0001), holding gender and race constant. Additionally, the AMXNOR exhibited a slight tendency to increase for each increasing grade of dysplasia but this could not be confirmed statistically.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoid cystic carcinoma: a study of nucleolar organizer regions (AgNOR) counts and their relation to prognosis

We studied the AgNOR counts in 30 cases of adenoid cystic carcinoma from salivary glands (n = 18) and non-salivary sites (n = 12) in an attempt to correlate them with the evolution of the disease. AgNOR counts per nucleus varied between 1.96 and 6.12 (mean value 4.2 +/- 0.99) as compared with 1.21 +/- 1.4 in normal salivary tissue. There was no significant difference between cases that had an unfavourable clinical outcome (recurrence, metastases, and/or died of the disease) and cases without disease complications (4.31 vs. 4.03 AgNORs per nucleus). No difference was found between tumours located at salivary and non-salivary sites or between major and minor salivary glands. AgNOR counts also did not correlate with the grade of differentiation of the neoplasms. In adenoid cystic carcinoma, AgNOR counts do not seem to be a prognostic indicator, in contrast to the usefulness of this method in other tumour types.

Nucleolar organizer regions in acute and chronic leukaemias

A silver staining technique for nucleolar organizer regions (NORs) has been applied to bone marrow biopsies of various types of acute and chronic leukaemias. This method could be easily evaluated on resin-embedded bone marrow obtained from acute lymphocytic leukaemia (n = 12), acute myelogenous (n = 16), chronic lymphocytic (n = 16) and chronic granulocytic (n = 20) leukaemia. A significant difference (p < or = 0.1) was only found between the AgNOR numbers in nuclei of lymphocytes from acute and chronic leukaemia (mean of 1.23 to 1.40 and 1.58) and those of cells from acute and chronic myelogenous leukaemia (from a mean of 5.00 to 9.17 per nucleus). However, no significant difference was observed among cells of various types of acute and chronic myelogenous leukaemias, despite of their markedly higher staining intensity and proliferative activity. The greatest mean of AgNOR numbers was counted in monoblasts of acute myelomonocytic leukaemia. It is suggested, that higher AgNOR counts in nuclei of more malignant leukaemic cells are in parallel with their mitotic activity and could be related to their elevated cell turn-over.

Importance of interphase nucleolar organizer regions in tumor pathology

The importance of the distribution of silver-stained nucleolar organizer regions (Ag-NORs) in interphase nuclei for diagnostic and prognostic purposes in tumor pathology has been reviewed. The available data demonstrated that interphase Ag-NOR evaluation may be of help in distinguishing malignant from hyperplastic or normal cells. On the other hand, there is increasing evidence that a relationship exists between the quantity of interphase Ag-NORs and the prognosis of malignant tumors: the greater the number of interphase Ag-NORs, the worse is the prognosis. This can be explained by the observation that the interphase Ag-NOR quantity is strictly related to the cell proliferation rate. The procedures used for the measurement of the interphase Ag-NOR quantity are also critically discussed.

Nucleolar organizer regions in malignant salivary gland tumors

Proliferative activity of carcinomas arising from salivary glands was analyzed by enumeration of argyrophilic nucleolar organizer regions (AgNORs). The mean numbers of AgNORs in the various tumors were as follows: mucoepidermoid carcinoma, 2.20; acinic cell carcinoma, 2.51; adenoid cystic carcinoma (ACC), 2.57; carcinoma in pleomorphic adenoma, 1.00 (benign component) and 3.99 (cancer-bearing area); salivary duct carcinoma, 4.49; polymorphous low-grade adenocarcinoma, 3.37; sebaceous carcinoma, 2.57; oncocytic carcinoma, 4.63; adenocarcinoma, 4.53. Cells of most tumors showed heterogeneous activity within the same tumor. In mucoepidermoid carcinoma, the mucous cells had suppressed activity in comparison with the epidermoid cells and intermediate cells. In ACC, the activity of the tumor cells increased according to growth pattern in the order tubular, glandular and solid. In carcinoma in pleomorphic adenoma, vigorous proliferative activity was observed in the malignant component, whereas less active cells were seen in the myxoid or chondroid matrix. AgNOR staining was useful for distinguishing benign from malignant regions in carcinoma in pleomorphic adenoma. Our results suggest that mucoepidermoid carcinoma, acinic cell carcinoma and ACC, except for that with a solid growth pattern, may be considered as low-grade malignancies, whereas solid-type ACC, the cancer component in carcinoma in pleomorphic adenoma and some of the other carcinomas have high-grade malignant behavior.

Nucleolar organizer regions (NORs) and myoepitheliomas: a comparison with DNA content and clinical course

Nucleolar organizer regions (NOR) were studied in 15 salivary gland myoepitheliomas by an argyrophilic staining technic (AgNOR). The AgNOR data were then compared with flow cytometric DNA content of the neoplasms and also with selected clinicopathologic parameters. We conclude that AgNOR's: (1) do not correlate well with DNA cytometric indices and (2) at best, provide redundant information.

Histopathology of malignant salivary gland tumours

This report is based upon the Salivary Gland Register in Hamburg and on the second revised edition of the WHO Histological Typing of Salivary Gland Tumours. The group of malignant salivary gland tumours contains carcinomas, malignant non-epithelial tumours, malignant lymphomas and secondary tumours. The various carcinomas are classified in a continuous separate listing because the different types are distinguished not only by histopathology, but also by differences in prognosis and treatment. The term "tumour" is replaced by "carcinoma" in two entities: acinic cell carcinoma and mucoepidermoid carcinoma. New entities are: polymorphous low-grade adenocarcinoma, basal cell adenocarcinoma, salivary duct carcinoma and malignant myoepithelioma. Carcinoma in pleomorphic adenoma can be distinguished as non-invasive and invasive carcinoma, and carcinosarcoma. Malignant non-epithelial tumours are mostly malignant fibrous histiocytoma, malignant schwannoma and rhabdomyosarcoma. The large majority of malignant lymphomas are non-Hodgkin-lymphomas with high differentiation. Many lymphomas are associated with chronic immunosialadenitis (Sjögren's syndrome). Secondary tumours are mostly metastases from primary squamous cell carcinomas or from melanomas of the skin (head and neck area). Haematogeneous metastases are very rare (mainly from lung, kidney or breast).

Argyrophilic nucleolar organizer regions in benign hyperplastic and cancerous human prostates

Argyrophilic nucleolar organizer regions (AgNORs) were examined histologically in cells of benign hyperplastic and cancerous human prostates. Individual dots of AgNORs inside nucleus that were stained as separate granules or as parts of clusters were counted as one, and the average number of dots per cell was obtained by counting 100 nuclei. The number in epithelial cells was similar to that in stromal cells of hyperplastic prostates. In cancerous prostates, the number was larger than in hyperplastic prostates and increased along with upgrading. The number in incidental cancers was smaller than in clinical cancers as compared with cells of the same Gleason pattern. Number correlated with T factor, but not with N and M factors. Response to treatment and cause-specific survival in stage D2 patients receiving endocrine therapy did not correlate with number, although a relationship between Gleason pattern and survival was shown in these patients. It was concluded that AgNORs might not be an indicator to predict prognosis after endocrine therapy, since a number of AgNORs did not influence response to the therapy.

Nucleolar organizer regions in the normal, hyperplastic and carcinomatous epithelium of endometrium

A silver colloid technique to identify nucleolar organizer region associated protein (AGNORs) has been applied to paraffin sections in a total of 43 endometrial hyperplasias (24 adenomatous and 19 adenocystic) 26 endometrial carcinomas and 22 normal endometria (11 of proliferative and 11 of secretory phase). A morphometric analysis of highly magnified photographic images of AGNORs in light microscopic preparations was performed. Malignant tumor cells showed significantly higher AGNOR numbers, maximum diameter and mean area compared with normal and hyperplastic endometrium, with the exception of adenocystic hyperplasia whose Dmax and mean area were significantly larger. Regarding the distribution pattern of AGNOR dots in the cases studied, it was found that normal and hyperplastic endometrium had a mainly clustered distribution while endometrial adenocarcinomas revealed a scattered one. The significant differences observed in the number of AGNORs, their size and mean area between benign and malignant endometrial epithelia suggest that the AGNOR staining technique is of diagnostic importance in distinguishing between these two groups.

Re-evaluating silver-stained nucleolar organizer regions (AgNORs) in problematic cutaneous melanocytic lesions: a study with quantitation and pattern analysis

Previous studies enumerating AgNORs in cutaneous melanocytic lesions have produced inconsistent results. It is probable that such inconsistencies arise from differences in fixation, staining technique, and counting strategies. Our group, having demonstrated an improved method of silver staining and having optimized counting, is now able to reconsider the role of AgNORs in evaluating borderline melanocytic lesions. Diagnostic problems similar to those encountered in routine practice have been examined. It is shown that only by counting intra- and extranucleolar AgNORs in combination with assessing the pattern of AgNOR dispersal is it possible to (1) discriminate dysplastic naevi from melanoma and (2) distinguish Spitz naevi and pigmented spindle cell naevi from melanoma. An analysis of AgNOR numbers alone results in considerable overlap between the groups studied. The value of assessing patterns of AgNOR dispersal within and outside clustered nucleolar structures is emphasized. Lesions labelled as minimal deviation melanoma (by experts in dermatopathology) were also investigated. The majority of these specimens form a distinct group lying apart from control naevi and melanomas. This finding, whilst of interest, is difficult to evaluate because of poorly defined diagnostic criteria.

Evaluation of the nucleolar organizer region associated proteins in minor salivary gland tumors

Forty-three intraoral salivary gland tumors were studied to determine the value of the AgNOR technique in the assessment of these neoplasms. Well defined black dots were visible in the nucleii of all the specimens studied. The mean AgNOR count per nucleus for each tumor was calculated as follows: pleomorphic adenoma (n = 15) 1.52; Polymorphous low-grade adenocarcinoma (n = 12) 1.90; adenoid cystic carcinoma (n = 6) 2.92; mucoepidermoid carcinoma (n = 4) 1.93; carcinoma ex mixed tumor (n = 4) 2.05; undifferentiated carcinoma (n = 1) 3.13 and epithelial-myoepithelial carcinoma (n = 1) 2.23. The difference between the means of benign and malignant tumors (P less than 0.01) and polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma (P less than 0.01) were highly significant. The overlapping of the AgNOR count between various tumors prohibited the use of this technique as an absolute criterion in establishing a final diagnosis. It could however be used as a diagnostic aid in differentiating between salivary gland neoplasms.

Mucoepidermoid tumors of salivary glands: histoprognostic value of NORs stained with AgNOR technique

A total of 31 patients surgically treated for salivary mucoepidermoid tumor had a comprehensive follow-up. Two groups were classified as: 16 with favorable outcome (no recurrence or late recurrences at 5 yr postoperatively and still alive; 15 with poor outcome (local recurrences before 5 yr, metastases, lethal evolution in 11 cases). We evaluated nucleolar organizer in every case, using AgNOR count. The AgNOR count seemed better than histologic criteria for establishing the prognosis of mucoepidermoid tumors. It correlated significantly with the clinical course: a high count was principally found in lethal forms, low counts (less than 1.8) were always detected in patients with a good outcome.

A critical evaluation of AgNOR counting in benign naevi and malignant melanoma

There is considerable variation in the quoted mean numbers of AgNORS per nucleus for benign melanonaevi and malignant melanomas. This is partly attributable to different approaches to AgNOR counting. This study summarizes our experience in devising an optimal technique for counting AgNORs. We show that it is essential to count intra-nucleolar AgNORs in addition to those lying outside the nucleolus to obtain clear separation of naevi from melanoma. Although this seems an onerous task, we further demonstrate that a maximum of only 30 nuclei need to be counted to obtain a mean AgNOR count per nucleus which is representative of the whole lesion. This compares with the arbitrary figure of 100 nuclei chosen by most workers. Only by optimizing and standardizing all aspects of the AgNOR technique including fixation, staining, and counting will mean AgNOR counts per nucleus become a useful quick, reproducible method which can be applied to lesions which pose diagnostic problems such as borderline melanocytic lesions.

Gold toning improves the visualization of nucleolar organizer regions in paraffin embedded tissues

A modification of the silver colloid technique for staining nucleoar organizer regions in paraffin embedded tissues is described. This modification involves the application of a gold toning step with subsequent gold reduction, if necessary, following incubation of sections in the standard silver colloid solution. Silver stained nucleolar organizer regions (AgNORs) in toned sections are more sharply delineated when compared to untoned controls. In high grade tumors the addition of the toning step results in significantly higher AgNOR counts due to the ability to discriminate more easily individual AgNORs in argyrophilic aggregates within the nucleus. It is recommended, because of enhanced visualization, that this modification of the silver colloid technique be used in studies involving quantification of AgNORs in tissue sections.

Argyrophilic nucleolar organiser region (AgNOR) staining in normal bone marrow cells

Fifteen normal bone marrow aspirates were stained with the agyrophilic nucleolar organiser region (AgNOR) method. The results of the specific staining AgNORs as well as nuclear and cytoplasmic staining were analysed. A system was devised to characterise precisely the AgNORs present in the nuclei of bone marrow cells. Particular types of bone marrow cells had a characteristic AgNOR and non-AgNOR staining pattern. The bone marrow cells were identified easily and reliably with AgNOR staining and the method was especially useful for lymphocytes, plasma cells, erythroid cells, basophils/mast cells, monocytes and cells containing haemosiderin. The immature haemopoietic cells exhibited more and larger AgNORs than the more mature cells. It is concluded that AgNOR staining can be used to study bone marrow cells by providing additional information when used in conjunction with conventional stains.

Intratubular germ cell neoplasia of the testis: identification by placental alkaline phosphatase immunostaining and argyrophilic nucleolar organizer region quantification

We assessed the value of placental alkaline phosphatase (PLAP) immunostaining and argyrophilic nucleolar organizer region (AgNOR) quantification as techniques for the identification of intratubular germ cell neoplasia (ITGCN), and compared them with hematoxylin-eosin and periodic acid-Schiff staining. We examined 46 malignant testicular germ cell tumors for the presence of ITGCN; 43 had sufficient tubules available for assessment. We also examined 16 cryptorchid testes, 16 testicular biopsies from 10 subfertile men, and 12 normal adult intrascrotal testes. In tubules adjacent to invasive tumors, hematoxylin-eosin staining identified 30 cases (70%) of ITGCN, while PLAP and AgNOR staining identified 36 cases (84%). All the seminomas (18) and 22 of 28 nonseminomatous germ cell tumors were PLAP-positive and had high AgNOR counts. Intratubular germ cell neoplasia was not identified in the other groups examined; germ cells in these groups were PLAP-negative and had low AgNOR counts. Cells of ITGCN showed cytoplasmic block positivity with periodic acid-Schiff staining but this was not a consistent finding. We conclude that ITGCN is present adjacent to most invasive germ cell tumors, and is reliably identified by hematoxylin-eosin staining when fully developed. Periodic acid-Schiff staining was not helpful as normal spermatogonia were also positive. Staining with PLAP and AgNOR were useful diagnostic adjuncts, but results with PLAP were easier to interpret.

Identification of nucleolar organizer regions in non-neoplastic and neoplastic hepatocytes by the silver-staining technique

The silver staining technique to demonstrate nucleolar organizer region (NOR)-associated proteins (AgNORs) was applied to a variety of liver tissues, including chronic persistent hepatitis (CPH), chronic active hepatitis (CAH), liver cirrhosis (LC), liver cell dysplasia (LCD), focal nodular hyperplasia (FNH), adenomatous hyperplasia (AH) and hepatocellular carcinoma (HCC). In the present study, only discrete, easily counted black dots within nuclei and silver-stained nucleolus were counted under a magnification of x400 without oil-immersion objectives. The mean AgNOR counts of HCC and LCD were significantly higher than that of normal hepatocytes, and 77% of cases of LCD and 56% of HCC had mean AgNOR counts more than 2, whereas those in CPH, CAH, LC, FNH and AH were always less than 2 and were not different from that of normal hepatocytes. Among HCC, the mean number of AgNORs increased with the grade of the tumor. However, the AgNOR counts of grade I HCC were always less than 2 and overlapped with those of normal hepatocytes and other benign categories. All cases with mean AgNOR counts of more than 2 turned out to be HCC, except LCD which exhibited characteristic histologic appearances easily distinguished from HCC. These findings suggest that AgNORs could be quantitatively useful in evaluating the grade of HCC, even under routine microscopic examination without oil-immersion objectives, and mean AgNOR counts of more than 2 per nucleus are hallmarks of HCC.

Nucleolar organizing regions (NORs) in pleomorphic adenomas of the salivary glands

The number of nucleolar organizing regions (NORs) can be used to reveal the degree of cell activity or metabolism in histopathology specimens. Forty-one cases of pleomorphic adenomas of the salivary glands were studied with a silver nitrate colloid staining method to demonstrate the NORs in the cells of the solid and duct pattern areas and in chondroid areas. Acinic and intercalated ducts cells of the surrounding normal salivary glands were also examined. The data was analyzed statistically and it was found that the cells in the solid/ductal areas had a higher cellular activity than the chondroid cells. This difference is probably directly related with the possibility of malignant transformation and the incidence of the different types of malignant pleomorphic adenomas. Furthermore, it is concluded that the number of NORs in pleomorphic adenomas to define malignancy should be done discriminating between the different histologic patterns because of their different metabolic activities.

Nucleolar organizer regions in gastric carcinoma and its precursor stages

A silver technique for nucleolar organizer regions (AgNOR) was applied to sections from 156 gastric biopsies and gastrectomy specimens. These included normal controls, normal gastric mucosa from carcinoma-bearing stomachs, intestinal metaplasia types I and III, dysplasia and carcinoma. AgNOR counts gradually increased from normal, through intestinal metaplasia, to carcinoma. This finding supports the chronic atrophic gastritis-intestinal metaplasia-dysplasia-carcinoma sequence concept for gastric carcinogenesis. Normal gastric mucosa was different from all lesions, including normal mucosa from carcinoma-bearing stomachs. Significantly higher AgNOR counts were observed in tumours compared to all other lesions except dysplasia. Dysplasia differed from intestinal metaplasia type I but not from type III. Eighty-five per cent of metaplasia cases overlapped with carcinoma and 19% with normal controls. The spread of AgNOR values in intestinal metaplasia reinforces the concept that this lesion is a heterogeneous entity reflecting a dynamic and continuous process. The AgNOR technique may contribute to the assessment of the stage of evolution of 'borderline' lesions.

Molecular biology and respiratory disease. 3. Evaluation of nucleolar organiser regions in pulmonary pathology

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Are AgNORs useful in distinguishing follicular hyperplasia from follicular lymphoma?

Argyrophilic nucleolar organiser regions (AgNORs) in 28 follicular lymphomas and 30 lymph nodes showing reactive follicular hyperplasia were studied to see if they were helpful in distinguishing follicular lymphoma from follicular hyperplasia in paraffin wax tissue sections. Mean nuclear counts were greater in follicular hyperplasia (3.71 v 3.11). This difference was significant but counts overlapped so much that they were of no practical value in distinguishing between both conditions. Higher counts may reflect greater proliferative activity in follicular hyperplasia.