Differentiation of malignant from normal and reactive mesothelial cells by the argyrophil technique for nucleolar organiser region associated proteins

Pseudosarcomatous Sclerosing Peritonitis

Chronic lupus peritonitis is uncommon, manifesting as ascites when other signs and symptoms of systemic lupus erythematosus are minimal, thus making diagnosis difficult. It is rarely the initial and only presenting symptom of systemic lupus erythematosus. We report such a case, which clinically and pathologically mimicked a malignant process. At laparotomy homogenous, thick, gray-white, firm tissue covered the bowel and other abdominal organs. Light microscopy showed a highly cellular, predominantly spindle-cell proliferation, raising the possible diagnosis of malignant peritoneal mesothelioma. A conservative approach was taken, and further investigation led to the definitive diagnosis of serositis associated with systemic lupus erythematosus. High-dose immunosuppressive therapy resulted in clinical and serologic improvement. The authors propose the term pseudosarcomatous sclerosing peritonitis to describe this unusually florid peritoneal reaction. The pathologic findings are discussed in the context of other reports of chronic lupus peritonitis, and the differential diagnosis of florid spindle-cell peritoneal reactions is considered.

Problems in mesothelioma diagnosis

Many centres are now seeing increasing numbers of patients with malignant mesothelioma. This presents pathologists involved in making the diagnosis with a number of problems, which can be divided into those encountered in making the distinction between mesothelioma and benign changes and those experienced in separating mesotheliomas from other types of epithelial and connective tissue tumours. Immunohistochemistry plays a major role in helping to make the diagnosis, but it should be interpreted with due regard to the clinical setting and radiological features, and with a knowledge of the wide morphological variations seen in mesothelioma. This review identifies some of these problems and addresses the uses and limitations of immunohistochemistry in different situations. It includes a discussion of some of the less common variants of mesothelioma and other pleural-based tumours that enter into the differential diagnosis.

Sensitivity and specificity of immunohistochemical antibodies used to distinguish between benign and malignant pleural disease: a systematic review of published reports

AIMS

A systematic review of published reports that have evaluated the ability of immunohistochemistry and argyrophil nucleolar organizing region (AgNOR) staining to distinguish between benign and malignant pleural disease.

METHODS

Nineteen relevant papers published during the period 1979-2005 were identified. Individual results of immunohistochemistry for five diagnostic antibodies were extracted to calculate diagnostic sensitivity and specificity. results from five of these studies that had evaluated proliferation markers or AgNOR staining techniques were also summarized.

RESULTS

Most antibodies demonstrated poor to moderate diagnostic ability. Desmin and epithelial membrane antigen (EMA) were the most useful, with sensitivity and specificity both above 74%. The combination of EMA and AgNOR was reported as having 95% diagnostic sensitivity. A high MCM2 labelling index also differentiated between benign and malignant pleural disease.

CONCLUSIONS

Immunohistochemistry is of limited value, but newer diagnostic methods may be useful additions in this area of pathology. The diagnostic importance of histological features seen on plain tissue sections is emphasized as vital for correctly differentiating between benign pleural disease and malignant pleural mesothelioma.

Expressions of proliferation markers (Ki-67, proliferating cell nuclear antigen, and silver-staining nucleolar organizer regions) and of p53 tumor protein in gestational trophoblastic disease

OBJECTIVE

This study was undertaken to determine whether the expressions of 3 proliferation markers (Ki-67, proliferating cell nuclear antigen, and silver-staining nucleolar organizer regions) and of p53 tumor protein could differentiate spontaneous abortions from gestational trophoblastic diseases and also discriminate among gestational trophoblastic disease subgroups.

STUDY DESIGN

Twenty-two partial hydatidiform moles, 17 complete hydatidiform moles, 6 invasive hydatidiform moles, and 20 nonhydropic spontaneous abortions (control group) were evaluated by means of immunohistochemical techniques with antibodies to Ki-67, proliferating cell nuclear antigen, and p53. One-step silver staining was used to detect silver-staining nucleolar organizer regions.

RESULTS

The expressions of Ki-67, proliferating cell nuclear antigen, silver-staining nucleolar organizer regions, and p53 were significantly higher in the gestational trophoblastic disease group than in the control group. The results of linear discriminant analysis showed that silver-staining nucleolar organizer region count had the highest sensitivity and specificity (93.3% and 100%, respectively) for distinguishing gestational trophoblastic disease from spontaneous abortion. Sensitivity and specificity for discriminating gestational trophoblastic disease from spontaneous abortion increased to 100% when all four markers were used together. Proliferating cell nuclear antigen was found to be the best discriminating variable for differentiating among gestational trophoblastic disease subgroups.

CONCLUSION

Our findings suggest that expressions of Ki-67, proliferating cell nuclear antigen, silver-staining nucleolar organizer regions, and p53 may aid in the diagnosis of gestational trophoblastic diseases. These fairly rapid, simple, and economic techniques could serve as a useful adjunct to conventional methods in the diagnosis of gestational trophoblastic diseases.

Quantitative cytological assessment of Ki67 and AgNORs using computer-digitized image analysis of four clinicopathological breast lesions

Analysis of silver-stained proteins associated with nucleolar organiser regions (AgNORs) is proposed as a marker of cellular proliferation. This study describes the application of AgNORs and Ki67 in breast lesions. Sixty-one cases including fibroadenoma (FA), fibrocystic disease (FCD), ductal carcinoma in situ (DCIS) and invasive carcinoma (IC) were studied by image analysis to evaluate quantitative changes in AgNORs in both Ki67-positive, and Ki67-negative smears. The Ki67 index was assessed. Morphometric features of cell nuclei and AgNORs were determined by digitized computer image analysis (Prodit 5.2). The growth fraction was 5.08 for FA, 5.71 for FCD, 16.75 for DCIS and 23.26 for IC. The mean nuclear area was significantly higher in malignant cells than those of fibroadenoma and fibrocystic disease. In Ki67-positive cells the total area, long axis and number of AgNORs increased progressively across disease groups. Eccentricity of AgNORs and AgNORs: nuclear area ratios were significantly increased in malignant breast lesion in comparison with benign lesion in Ki67 positive cells. In Ki67 negative cells, the highest value of AgNORs was observed in DCIS. The AgNORs: nuclear area ratio demonstrated a statistically significant trend across the disease groups. This study demonstrates that the growth fraction, mean nuclear area and selected AgNORs features have potential for differentiating benign from malignant breast tumours.

Assessment of nucleolar organizer regions (NORs) in proliferative conditions of the liver

To overcome the diagnostic dilemma in proliferative conditions of the liver which sometimes pose a problem to the working pathologist especially when the material is inadequate, a special staining technique (AgNOR) has been applied. By using this technique, nucleolar organizer regions were counted which determine the proliferative status of the cells. This prospective study included 65 cases of randomly selected liver core and fine needle aspiration biopsies. AgNOR staining was performed on formalin-fixed, paraffin-embedded tissue sections NOR dots were counted in 100 randomly selected hepatocytes at x100 oil immersion objective, and the mean count per cell was calculated for each case. Statistical analysis was done by using the Mann Whitney U test. AgNOR count results were later compared with the histologic diagnosis. The study revealed a gradual increase in mean AgNOR counts from normal liver through cirrhosis to hepatocellular carcinoma. The difference in NOR counts was significant in these three groups. The hepatocellular carcinomas were graded according to the Edmondson-Steiner histological grading system. The Grade I hepatocellular carcinomas show AgNOR counts ranging between 5-6/cell, a score which is much higher than in the normal liver, where it ranges between 1.2-2.0/cell. This technique can be used to assess the lesions where the distinction between normal liver and Grade I hepatocellular carcinoma is difficult with the use of routine methods. AgNOR counts in normal liver and chronic hepatitis cases were insignificant, but there was an appreciable difference between cases of chronic hepatitis, cirrhosis and hepatocellular carcinoma. In view of the results of this study, the AgNOR staining method is found to be a useful diagnostic tool to differentiate between normal liver, cirrhosis and hepatocellular carcinoma and also to precisely discriminate between cases of normal liver and Grade I hepatocellular carcinoma.

AgNORs in benign, borderline and transitional cell neoplasms of the urinary bladder

Argyrophilic nucleolar organizer regions (AgNORs) were studied in 106 tissue samples from the urinary bladder (6 normal transitional epithelium, 5 cystitis, 12 hyperplastic, 14 dysplastic lesions, 12 carcinoma in situ, 4 transitional cell carcinoma grade 0, 12 grade I, 15 grade II and 12 grade III) to evaluate their role in differentiating benign, borderline and malignant lesions. The NOR counts presented a rising scale from normal (2.21), inflammatory (3.93 for both cystitis and hyperplasia), dysplastic (4.16), carcinoma in situ (5.08) to malignant lesions (5.28 grade I, 6.59 grade II and 8.37 grade III). It was concluded that AgNORs do not have a diagnostic role in these lesions, but that they can act as a reliable adjunct to existing parameters in the early detection of tumour recurrence and grading of malignant neoplasms.

The use of epithelial membrane antigen and silver-stained nucleolar organizer regions testing in the differential diagnosis of mesothelioma from benign reactive mesothelioses

BACKGROUND

The accurate diagnosis of pleural lesions obtained from small closed biopsy is difficult. As yet there is no single reliable test to distinguish between malignant and benign mesothelial tissue.

METHODS

Immunostaining of epithelial membrane antigen (EMA) and the quantitation of silver stained nucleolar organizer regions (AgNORs) each were applied to benign and malignant histologic sections of pleural and peritoneal biopsies. The usefulness of these stains was tested both individually and in combination in the diagnosis of epithelial malignant mesothelioma.

RESULTS

One hundred and three of the 141 malignant lesions (73%) were immunoreactive for EMA but only 3 of the 73 benign lesions (4%) reacted equivocally, and none positively. The average count of AgNORs/cell in malignant lesions (n = 80) was elevated compared with benign cases (n = 26), but a significant overlap was exhibited in the AgNOR count and this form of analysis was considered to be of little value in distinguishing benign from malignant mesothelial processes. Much less overlap was observed when the average AgNOR area was measured. By using the maximum benign AgNOR area of 0.6677 microm2 as the upper threshold, 51 cases (63.8%) were identified as malignant; the test demonstrated 100% specificity and 63.8% sensitivity. By combining the EMA and AgNOR results, 76 of 80 of the malignant mesothelioma cases (95%) tested positive for at least 1 of the tests with no false-positive results identified.

CONCLUSIONS

This study confirms the usefulness of EMA in diagnosing malignant and benign mesothelial lesions, and demonstrates the enhanced diagnostic value of combining EMA immunoreaction with the average area of AgNOR per cell, thereby increasing sensitivity in the diagnosis of epithelial malignant mesothelioma.

Nucleolar organizer regions and prognosis in glottic squamous cell carcinoma

BACKGROUND

The quantity of nucleolar organizer regions (AgNORs) appear to be prognostic significant in several tumor types.

METHODS

Sections from 93 routinely processed pretreatment biopsies from patients with glottic carcinomas were stained by silver nitrate and evaluated by two counting methods: (1) the mean number of AgNOR per tumor nucleus (mAgNOR), and (2) the number of tumor nuclei with one, two, three, four, and more than four AgNOR grains. From these figures the percentage of nuclei with one, two or less, three or less, and four or less AgNORs (pAgNOR1, aAgNOR < or = 2 etc) were calculated.

RESULTS

The median mAgNOR was 4.3, and low counts correlated favorably with the disease-free period (p = 0.0433). The median percentages for pAgNORs were 14, 26, 38, and 51 for pAgNor1, PAgNOR < or = 2, pAgNor < or = 3 and pAgNOR, < or = 4 respectively. Values above the medians correlated positively with the disease-free period (p-values ranging from 0.0005 to 0.0001). Although pAgNOR < or = 3 appeared to be the best discriminator by multivariate analysis, pAgNOR1 is the method of choice because this parameter is the easiest and quickest to perform.

CONCLUSION

pAgNOR counts appear to be a potent prognostic marker and may become useful in treatment decisions.

Pleural mesothelioma: an approach to diagnostic problems

In the 1960s, a close relationship between heavy exposures to crocidolite asbestos and mesothelioma was established. The debate on the diagnosis of mesothelioma became complicated because of the possibility of litigation. Well differentiated mesothelioma cells are mucicarmine negative but alcian blue and periodic acid-Schiff (PAS) positive, which are removed by hyaluronidase and diastase digestion. By electron microscopy (EM), they show bush-like elongated, slender, and branching microvilli. By immunohistochemistry they express both keratin and vimentin but not carcinoembryonic antigenicity (CEA), B72.3, Ber-EP4, and Leu-M1. In poorly differentiated mesotheliomas, chromosomal and molecular biological alterations are common and complex but these alterations also overlap with that of poorly differentiated tumours of the lung and other organs. A poorly differentiated pleural tumour is most likely metastatic and needs good team work to locate the primary site. The diagnosis of a mesothelioma and asbestosis should be established separately. Future studies will be focused less on the phenotypic differences but more on the broad molecular and multi-phasic mechanisms of carcinogenesis, irrespective of the aetiological agents, in poorly differentiated tumours.

Comparison of silver-staining nucleolar organizer region (AgNOR) counts and proliferating cell nuclear antigen (PCNA) expression in reactive mesothelial hyperplasia and malignant mesothelioma

Previous workers have used counts of colloidal silver-stained nucleolar organizer regions (AgNORs) to help distinguish reactive from malignant mesothelial processes. We sought to compare the demanding technique of AgNOR counting with the identification of proliferating cell nuclear antigen (PCNA) in 10 pleural malignant mesotheliomas and 11 reactive mesothelial proliferations. The mean AgNOR count was significantly higher in malignant compared to reactive lesions (5.10 [95% confidence interval, CI 4.35-5.84] vs 3.68 [95% CI 3.17-4.19], p = 0.004), as was the PCNA index (26.9 [95% CI 17.37-36.49] vs 9.67 [95% CI 4.94-14.39], p = 0.004). Less overlap was seen with PCNA indices and no reactive mesothelial proliferations had a PCNA index greater than 20%, suggesting that scores over this level may be a specific indicator of malignancy in this setting. There was only a weak correlation between the 2 proliferation indices suggesting that PCNA and AgNORs are present at somewhat different times of the cell cycle and/or persist in the post-S phase cell for variable lengths of time.

Comparison of nucleolar organiser regions and DNA flow cytometry in the evaluation of pleural effusion

BACKGROUND

In conventional cytological diagnosis of pleural effusions the assessment of morphological features plays an important part. However, false negative and false positive results may occur. In this study conventional cytology was compared with flow cytometric DNA analysis and the argyrophil staining technique for nucleolar organiser regions (AgNOR) to characterise benign and malignant effusions.

METHODS

Pleural effusions from 71 patients (38 with benign lung disease, 33 with proven adenocarcinoma of lung) were studied by conventional cytology, flow cytometric DNA analysis, and the AgNOR technique. Tumour cell ploidy was determined by flow cytometry. In an attempt to detect the cell proliferative state, flow cytometric S phase fraction and the AgNOR technique were used. The correlations among conventional cytology, flow cytometric DNA ploidy, S phase fraction analysis, and nucleolar organiser regions were investigated.

RESULTS

All the 38 benign pleural effusions were diploid. There were 17 (52%) aneuploid and 16 (48%) diploid malignant pleural effusions. Based on these results this type of DNA analysis had a sensitivity of 52% and a specificity of 100%. The mean (SD) numbers of flow cytometric S phase fractions of benign and malignant cases were 5.32 (1.67)% and 12.45 (3.93)% respectively. The mean numbers of S phase fractions of diploid malignant cases were higher than diploid benign cases. In each case the number of AgNORs was counted in 100 cells. The mean number of AgNOR dots per nucleus was 12.57 (3.64) for malignant pleural effusion cells and 3.96 (1.39) for benign pleural effusion cells. The mean number of AgNOR dots was 14.45 (3.36) for aneuploid malignant pleural effusion cells and 10.57 (2.82) for diploid malignant pleural effusion cells. The AgNOR numbers were higher in diploid malignant cells than in diploid benign cells. There was a significant correlation between the S phase fraction determined by flow cytometry and the mean number of AgNORs per nucleus in malignant cases.

CONCLUSIONS

Both flow cytometry and the AgNOR methods provide comparable measurements in the diagnosis of pleural effusion. The study also indicates that the AgNOR method, which is rapid and easy to perform, may be a useful adjunct to flow cytometry, S phase fraction analysis and conventional cytology in the routine diagnosis of malignant pleural effusion.

Malignant peritoneal mesothelioma mimicking mesenteric inflammatory disease

A case of malignant peritoneal mesothelioma mimicking mesenteric inflammatory disease (MID) is presented. The patient had mesenteric and omental lesions characterized at biopsy by extensive fibrosis of fat tissue with mild to moderate inflammation. One year later, post-mortem examination revealed a well-differentiated epithelial mesothelioma. Immunohistochemical stains for keratin and vimentin were diffusely positive, whereas EMA showed a membranous staining of scattered cells. CEA, Ber-EP4, B72.3 and Leu-M1 were negative. In addition, actin monoclonals decorated groups of cells pertaining to the tumoural component. Immunostains of sections from retrieved paraffin blocks of the previous biopsy showed that the bulk of the spindle-shaped and histiocytic-like cells present in the fibrous streams was strongly labeled by low-molecular-weight keratin, and coexpressed vimentin and actin. EMA showed a membranous staining of sporadic spindle and round cells. The other immunostains were invariably negative. This immunohistochemical pattern closely corresponded to the immunophenotype of the mesothelial tumour detected at autopsy and was very suggestive of myofibroblastic/submesothelial cell origin. The quantitative evaluation of silver nucleolar organizer regions (Ag-NORs) demonstrated high levels of cell proliferation in both surgical and autopsy tissue samples.

Giant cell lesions of the jaws: evaluation of nucleolar organizer regions in lesions of varying behavior

To examine whether giant cell lesions of the jaws (GCL) of varying behavior could be separated histologically, a number of GCL were studied using the AgNOR staining technique for nucleolar organizer regions. The mean AgNOR count of mononuclear cells from recurrent lesions (1.73 +/- 0.15) was slightly higher than that of the aggressive lesions (1.54 +/- 0.21) and much higher than that of the non-aggressive/non-recurrent lesions (1.33 +/- 0.14). Similarly, the mean AgNOR count of the multinucleate giant cells of the recurrent lesions (1.52 +/- 0.14) was slightly higher than that of aggressive lesions (1.34 +/- 0.092) and much higher than that of non-aggressive/non-recurrent lesions (1.26 +/- 0.05). Statistical analysis showed a significant difference between the mean number of AgNORS of recurrent lesions and non-recurrent/non-aggressive ones in both the mononuclear and multinuclear population (p < 0.05).

Nucleolar organiser regions of mesothelial and carcinomatous cells in effusions

The AgNor reaction was performed on effusions and peritoneal washings, and the silver dots were counted on normal or reactive mesothelial cells vs. carcinomatous cells, ascertained by previous HE staining. The mean values were 1.64 for the former (n = 20) and 4.90 for the latter (n = 10). The intersection between the two group distributions was 2.78, leaving a chance of only 0.65% for a false-positive result. The method may thus be helpful in the interpretation of doubtful cytological cases.

Argyrophilia in nucleolar organizer regions (AgNOR) in adenoid cystic carcinoma and polymorphous low-grade adenocarcinoma of the salivary glands

Nine cases of adenoid cystic carcinomas (ACC) and three cases of polymorphous low-grade adenocarcinomas (PLGA) of the salivary glands from the Surgical Oral Pathology Service of the University of São Paulo School of Dentistry were examined by means of the silver-staining nucleolar organizer regions (AgNOR) technique. Quantitative and dimensional analyses of NORs were carried out. Our findings suggest that solid and cribriform patterns of ACC have a higher cellular activity than that presented by tubular ACC and PLGA.

Nucleolar and dispersed nucleolar organiser regions (NORs) in differentiating neoplastic from atypical non-neoplastic lesions of the pancreas

Our objective was to compare the accuracy of differentiation of pancreatic carcinoma from the benign ductular aggregation of chronic pancreatitis using two methods, nuclear morphometric analysis and modified argyrophilic nucleolar organiser region (AgNOR) staining for nucleoli and dispersed NORs (AgNU staining). We evaluated 35 metastatic or invasive lesions of pancreatic carcinoma with low-grade atypia, 16 lesions of ductular aggregation and 12 lesions of proper epithelium. Four parameters, consisting of the size of nucleus: mean area, mean minor axis, mean major axis and mean perimeter, and two parameters of AgNu staining: mean number of AgNu-stained dots per nucleus (equal to mean number of nucleoli and dispersed NORs) and mean area of the largest AgNu-stained dot (equal to mean area of the largest nucleolus) of pancreatic carcinomas were significantly larger than those of ductular aggregations and of proper epithelia. In the discriminant analysis of four parameters of nuclear size, the discrimination of carcinomas was correct in 82.9% and that of ductular aggregations in 81.3%. Discriminant analysis by two parameters of AgNu staining showed 2 correct discrimination of lesions in 88.6% and 100%. Thus, AgNu staining was more accurate than nuclear morphometric analysis in discriminating a pancreatic carcinoma from ductular aggregation.

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 silver staining patterns and HLA-DR antigen expression in bronchial epithelial cells in chronic bronchitis

Bronchial epithelial cells obtained by brush biopsy during fiberoptic bronchoscopy performed in 12 patients with chronic bronchitis and 12 healthy control subjects, were investigated for HLA-DR antigen expression and nucleolar silver staining patterns. In all patients with chronic bronchitis the number of bronchial epithelial cells positive to HLA-DR antigen was highly increased (> 90%), whereas in the controls only a few epithelial cells (< 10%) showed a weak HLA-DR antigen expression. Patients with chronic bronchitis showed an increased lymphocytic reaction compared to the control subjects. Both in the patients with chronic bronchitis and in the healthy controls the number of nucleoli was the same. The number of silver stained dots per nucleus was significantly higher in patients with chronic bronchitis than in the control subjects (7.70 +/- 0.87 as against 5.11 +/- 0.52; p < 0.0001). The intensity of the lymphocytic reaction correlated with the HLA-DR antigen expression and the increase in silver staining (Spearman's r = 0.543; p < 0.01). This indicates the influence of inflammation on the activation of epithelial cells derived from the respiratory tract.

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.

Correlation between nucleolar organizer regions visualized by silver staining and the growth rate in lung adenocarcinoma

BACKGROUND

The value of nucleolar organizer regions (NOR) visualized by silver staining (AgNOR) for the histologic differentiation, pathologic staging, and estimation of growth rate was assessed by the investigation of paraffin sections from 58 lung adenocarcinomas. AgNOR consist of NOR-associated proteins, and the number of AgNOR might be related to proliferative activity.

METHODS

In lung adenocarcinoma, the growth rate can be measured by means of chest radiographs. Using this technique, the authors studied the correlation between the mean number of AgNOR and growth rate.

RESULTS

The mean number of AgNOR ranged from 1.8 to 6.3 (mean +/- standard deviation, 4.0 +/- 0.8). Neither the degree of histologic differentiation nor the pathologic staging was related to the AgNOR count. The tumor growth rate was estimated on the basis of the doubling time in the chest radiographs of 13 patients. The doubling time ranged from 80 to 760 days. There was a high inverse correlation between the AgNOR count and the doubling time (r = -0.910; P less than 0.001).

CONCLUSIONS

Thus, it appears to be possible to use the mean number of AgNOR as an index of proliferative activity.

Evaluation of AgNOR count in distinguishing benign from malignant mesothelial cells in pleural fluids

The authors have evaluated in eight reactive and eight malignant pleural effusions the number of intranuclear dots representing the nucleolar associated proteins stained with silver colloid technique (interphase nucleolar organizer regions-AgNORs). The mean number per nucleus in benign reactive effusions was 1.56 (SD 0.77) while in mesotheliomatous effusions it was 2.81 (SD 1.44). The statistical analysis of values, by Mann-Whitney U Wilcoxon Rank Sum W Test, revealed a significant difference of AgNOR counts in the two cytological samples. The variability of AgNOR areas and morphologies in reactive and mesotheliomatous nuclei in pleural fluids is evaluated applying automatic image analysis.

Quantitative analysis of nucleoli and nucleolar organizer regions in cultured primary human normal, reactive and malignant mesothelial cells

The number and the size of silver-stained intranuclear granules, which correspond to the nucleolus and nucleolar organizer regions, have been determined by means of quantitative methods in cultured primary human mesothelial cells obtained from normal, reactive and malignant mesothelium. The mean values per nucleus of the number, the total area, the average area, and the relative area of the silver-stained granules and the mean nuclear area were determined for each of the three conditions. Normal, reactive and malignant mesothelial cells differed significantly in all the features. These findings at the optical level reflect the differing rate of the nucleolar biosynthetic activity related to the different biological properties of the three cell types, and the features can be useful morphometric descriptors in the diagnostic pathology of the mesothelium.

Nucleolar silver staining patterns of lymphocytes in sarcoidosis

Bronchoalveolar lavage lymphocytes from 15 patients with pulmonary sarcoidosis and 8 healthy controls were investigated for nucleolar silver staining patterns and lymphocyte subpopulations. Patients with sarcoidosis had increased numbers of silver stained dots versus controls (2.20 +/- 0.24 versus 1.78 +/- 0.07; p less than 0.001). The number of silver stained dots showed the strongest positive correlation to helper cells (OKT 4+) (r = 0.781; p less than 0.0001). These results may be interpreted as further evidence of lymphocytic activation, especially of helper cells (OKT 4+) in pulmonary sarcoidosis.

Correlation of morphological patterns of nucleoli in alveolar macrophages with HLA-DR antigen expression in sarcoidosis

BACKGROUND

Alveolar macrophages from patients with sarcoidosis express increased quantities of HLA-DR during activation. Because silver staining has been described as a sensitive indicator of cellular activity a study was performed to examine whether it relates to HLA-DR antigen expression.

METHODS

The relation between silver staining patterns of nucleoli and HLA-DR antigen expression was examined in alveolar macrophages collected by bronchoalveolar lavage from 11 patients with pulmonary sarcoidosis and 11 control subjects.

RESULTS

The mean (SD) number of silver stained protein dots associated with the nucleolar organiser regions (AgNORs) was significantly higher in alveolar macrophages from patients with sarcoidosis (7.5 (1.5)) than in those from control subjects (5.6 (0.6)). The number of silver stained dots in alveolar macrophages correlated significantly with the intensity and the density of HLA-DR antigen expression in the patients with sarcoidosis.

CONCLUSIONS

Silver staining may be a sensitive tool for the investigation of the biological cell activity of alveolar macrophages in sarcoidosis.

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.

Interphase nucleolar organiser regions and survival in squamous cell carcinoma of the bronchus: a 10 year follow up study of 138 cases

BACKGROUND

Good prognostic indicators for patients with squamous cell carcinoma of the lung would help to determine the most appropriate treatment for individual patients.

METHODS

A silver colloid technique that shows interphase nucleolar organiser regions (AgNORs) has been applied to representative paraffin sections from 138 cases of squamous cell carcinoma of the bronchus treated by surgical resection of the primary tumour at East Birmingham Hospital in 1977. Of the 138 patients, 23 (17%) were alive 10 years after their operation.

RESULTS

The mean (SD) AgNOR count per cell was significantly higher for all grades of malignancy (well differentiated 10.5 (2.6), moderately differentiated 10.7 (3.2), and poorly differentiated 12.7 (4.5)) than for normal pseudostratified columnar epithelium from non-affected areas (2.3 (0.78)). There was a trend for AgNOR counts to be higher in poorly differentiated tumours, but a wide range of AgNOR counts was observed in all histological grades. AgNOR counts did not predict clinical outcome, irrespective of the stage of the disease, and did not relate to DNA ploidy or the percentage of cells in the proliferation phase of the cell cycle. Nine of 47 patients (19%) with tumours classified as DNA diploid and eight of 63 patients (13%) with DNA aneuploid tumours were alive 10 years after operation. Principal component analysis identified the clinicopathological stage of disease as the variable best related to survival. The percentage of patients surviving 10 years was 30% for stage I, 20% for stage II, 10% for stage IIIa, 9% for stage IIIb, and none for stage IV.

CONCLUSION

The AgNOR technique is not of prognostic value in postoperative patients with squamous cell carcinoma of the bronchus.

Silver-stained nucleolar organizer regions in the normal, hyperplastic and neoplastic endometrium

The numbers of silver-stained nucleolar proteins (AgNORs) were counted in hyperplastic and neoplastic lesions of the endometrium and compared with those of normal proliferative and secretory phase endometrium. In glandular cells in the normal menstrual cycle, the mean number of AgNORs in proliferative phase endometrium (3.8) was significantly higher than that in secretory phase endometrium (2.7, P less than 0.05). The mean number of AgNORs in well-differentiated endometrioid type adenocarcinoma (5.5) was significantly higher than that in both complex hyperplasia without cytological atypia (3.6, P less than 0.01), and simple hyperplasia (3.3, P less than 0.01). Mean AgNOR counts in complex hyperplasia with cytological atypia were greater than those in both complex hyperplasia without cytological atypia (P less than 0.05) and simple hyperplasia (P less than 0.05). Thus, complex hyperplasia with cytological atypia appears to be a direct precursor of well-differentiated endometrioid type adenocarcinoma. These findings suggest that the mean numbers of AgNORs are increased in neoplastic changes in the endometrium, and the one-step colloid method for AgNORs may therefore be a simple and useful technique to examine proliferative activity in neoplastic and pre-neoplastic endometrial cells.

The differential diagnosis of epithelial-type mesothelioma from adenocarcinoma and reactive mesothelial proliferation

Three monoclonal antibodies (mAbs) have been applied to 14 adenocarcinomas, eight mesotheliomas, and nine reactive mesothelial proliferations. One of these, AUA1, is a novel antibody in this context. It was found in 13/14 of the adenocarcinomas but not in benign or malignant mesothelial tissue, making it a potential substitute for carcinoembyronic antigen (CEA) in the differential diagnosis of mesotheliomas from adenocarcinomas. In addition, the lesions were stained using an argyrophil technique to identify nucleolar organizer regions. The results of counting these showed a small but significant overlap in their numbers between malignant and benign mesothelial proliferations. Although there was a difference overall in the numbers of nucleolar organizer regions in adenocarcinomas and mesotheliomas, on the one hand, and benign hyperplasias, on the other, this overlap considerably reduces their value in assessing individual difficult cases.

Nucleolar organizer regions in endometriosis, atypical endometriosis, and clear cell and endometrioid carcinomas

Nucleolar Organizer Regions (NORs) code for ribosomal RNA and are thought to be an accurate representation of the percentage of cells in S-phase. NORs are associated with nonhistone nucleoproteins, which can be stained with silver (AgNORs). An increased number of AgNORs has been observed in many malignancies. AgNORs were counted in three groups of patients with endometriosis (Group I), atypical endometriosis (Group II), and clear cell or endometrioid carcinomas (Group III) to assess the malignant potential of atypical endometriosis. Each group consisted of 10 patients. Mean AgNOR counts were 5.83 (Group I), 7.68 (Group II), and 15.42 (Group III). The results were analyzed and were significantly different for all groups (P less than 0.05 for Groups I and II, P less than 0.02 for Groups II and III, and P less than 0.01 for Groups I and III). A critical AgNOR count of 8.20 was calculated utilizing AgNOR counts from Group I. Three of the four patients with AgNORs greater than 8.20 and atypical endometriosis developed a malignancy. AgNOR counts provide useful information, represent an inexpensive test which can be obtained from fixed tissue, and may aid in clinical management of patients with atypical endometriosis.

AgNOR staining in benign hyperplasia and carcinoma of the prostate

We have modified existing techniques for silver staining of nucleolar organizer regions of intact interphase cells by hypotonic swelling and by formic acid treatment to reduce background staining. This allowed the microscopic identification and counting of individual AgNORs in the nucleoli. The method was used on nine adenomatous prostatic samples (including one of normal prostate tissue outside a localized tumor) and on seven prostatic adenocarcinomas. In general, the adenomatous samples displayed fewer AgNORs (mean 13 dots/cell) than did the carcinomas (mean 24 dots/cell). Although no cells with very high AgNOR counts were found in specimens from nonmalignant tumors, two of the adenomatous prostates did have AgNOR profiles that to a large extent overlapped with those of carcinomas. A highly differentiated carcinoma (of which only very small amounts were present in the sample) had low AgNOR counts. The three moderately differentiated carcinomas had more silver-positive material than the nonmalignant prostates but less than the three poorly differentiated carcinomas. The latter tumors also had a substantial proportion of cells with greater than 60 AgNOR counts, something that was never seen in carcinomas with higher differentiation. The data indicate that analysis of silver staining-positive material in intact interphase cells may help distinguish between benign and malignant prostatic tumors and between highly malignant and low malignant carcinomas.

Acrocentric interconnections and NOR variants in human lymphocytes

Acrocentric interconnections and NOR (nucleolus organizer region) variants are frequently observed in silver-stained metaphase preparations from lymphocytes of phenotypically normal individuals. The types of interconnections and of NOR variants are outlined. It is speculated that the satellite acrocentrics (both normal and variant) are the consequence of breakage and recoiling of these interconnections. Awareness of these two features of the human genome may facilitate understanding of the NOR/nucleolus interaction(s) in such important processes as nucleolus formation and in development and/or diagnosis of disease states (i.e., malignancy).

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.

Argyrophilic nucleolar organizer region proteins (Ag-NORs) in human brain tumors: relations with grade of malignancy and proliferation indices

Proliferation indices and mean number of silver-stained nucleolar organizer region-associated proteins (Ag-NORs) are compared in 65 brain tumors, including 34 gliomas, 8 meningiomas, 17 metastatic tumors, and 6 other tumors. Immunocytochemical investigations include labeling with the monoclonal antibody Ki-67 which identifies the whole growth fraction, and with a monoclonal antibody against bromodeoxyuridine (BrdUrd) which detects cells in the S phase of the cell cycle after in vitro incubation with BrdUrd. When all types of tumors are collectively considered, mean numbers of Ag-NORs did not correlate with Ki-67 and Brd-Urd labeling indices (LIs) and mitotic index. Among tumor subtypes, only meningiomas showed significant correlations between Ag-NOR counts, LIs, and malignancy. Mean number of Ag-NORs did not correlate with proliferation indices and tumor grade in low-grade and high-grade gliomas. However, recurrent high-grade gliomas showed a tendency to higher Ag-NOR counts than primary tumors. This study indicates that counting of Ag-NORs in paraffin sections is of limited value in tumor neuropathology. Correlations found in meningeal tumors should be substantiated in larger series.

Nucleolar organizer regions in normal, hyperplastic and neoplastic parathyroid glands

Using a one-stage silver staining technique, nucleolar organizer regions (AgNORs) were studied in paraffin sections of parathyroid glands (and in two lymph node metastases) from patients operated upon because of hyperparathyroidism or thyroid disease. The parathyroids were microscopically differentiated into normal, hyperplastic, adenomatous and carcinomatous glands. AgNORs were observed as distinct black dots of varying size and somewhat varying configuration in the nuclei of all glands. The mean number of AgNORs in the hyperplastic and adenomatous glands was not significantly different from that in the normal glands, whereas the carcinomatous glands exhibited significantly increased mean AgNOR number. No evidence was obtained for a role of AgNOR counting in the differentiation between normal and hyperplastic or adenomatous parathyroids, but the results suggest a potential role of enumeration of AgNORs in the discrimination between benign and malignant parathyroid neoplasms.

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.

Role of nucleolar organiser regions in differentiating malignant from benign tumours of the colon

An argyrophilic technique (AgNOR) was applied to paraffin wax sections of 12 tubular adenomas, 17 villous adenomas with moderate and severe atypia, and 21 colonic adenocarcinomas. The range of the mean number of nucleolar organiser regions (NORS) per nucleus was 1.54-3.28 (99% CI 2.29-3.04) for tubular adenomas 3.07-4.36 (2.98-4.43), and 3.60-5.02 (3.74-4.69) for villous adenomas with moderate and severe atypia, respectively, and 5.53-9.33 (6.15-8.54) for highly differentiated adenocarcinomas. The number of AgNORs permitted differentiation among the three groups. The differences observed were significant. Malignant tumour cells were characterised by a large number of AgNORs which were small in size and showed a scattered distribution. Nuclei of tubular adenoma and villous adenoma with moderate atypia had only a small number of large sized AgNORs in a clustered distribution. It is suggested that this method distinguishes malignant epithelial cells from benign cells of colon, even those with severe atypia, and that it is a useful adjunct to diagnostic histopathology.

Do AgNOR counts reflect cellular ploidy or cellular proliferation? A study of trophoblastic tissue

There is considerable debate as to whether AgNOR counts reflect cellular ploidy or cellular proliferation. Trophoblastic tissue from hydropic abortions and from hydatidiform moles offers an excellent model for analysing this problem. Thus, complete moles show considerable cell proliferation but are diploid, whilst partial moles show markedly less cell proliferation but are triploid: hydropic abortuses are diploid and show no cellular proliferation. AgNOR counts in villous cytotrophoblastic cells from hydropic abortions and from complete hydatidiform moles are similar, but those in partial hydatidiform moles are 50 per cent higher than in either hydropic abortions or complete moles. Thus, in non-neoplastic trophoblastic tissue AgNOR counts are clearly a reflection of ploidy rather than of cell proliferation.