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

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

Images

Gastric dysplasia: inter-observer variation, sulphomucin staining and nucleolar organizer region counting

Gastric dysplasia is regarded as a pre-neoplastic lesion and is generally believed to have higher potential for malignant transformation with increasing grade. To obtain consistency in diagnosis and management, reproducible diagnostic criteria are needed. We have used the classification system of the International Study Group on Gastric Cancer--ISGGC and investigated the interobserver variation in histological diagnosis. A Kappa statistic of 0.579, which reflects moderate agreement, was obtained for variation between two experienced pathologists. The prevalence of type III intestinal metaplasia was studied and found to occur in 55% of dysplastic areas, but in only 9% of hyperplastic areas (P less than 0.01). In addition, the correlation of mean nucleolar organizer region (AgNOR) counts with diagnostic categorization was investigated. A significant inter-observer variation was found between an experienced pathologist and a postgraduate student and only one of the observers obtained statistically significant separation of mean AgNOR counts between the categories of high-grade dysplasia, low-grade dysplasia, atypical hyperplasia, simple hyperplasia and normal.

Nucleolar organiser regions as indicators of post-surgical prognosis in canine spontaneous mast cell tumours

The average number of nucleolar organiser regions per cell has previously been shown to correlate well with histological grading techniques for a variety of neoplasms in man, and may thus be of value as an aid to post-surgical prognosis. In this study 50 spontaneously arising, subcutaneous canine mast cell tumours were graded and the histological grade compared with the mean AgNOR count. For well differentiated neoplasms the mean count was 1.4 per cell compared with 6.3 for poorly differentiated neoplasms, while tumours of intermediate differentiation had a mean count of 3.2 per cell. Subsequent follow up studies revealed that the AgNOR count was an accurate prognostic indicator, 73% of dogs with a high mean count (greater than 4.9) being destroyed from tumour related disease compared with 33% with an intermediate count (1.7-4.8). No dog with a count of less than 1.7 has been destroyed because of tumour recurrence to date and the AgNOR count has proved to be a better and more objective prognostic indicator than either histological tumour grade or mitotic index. Since most dogs which develop recurrent mast cell tumours do so within 6 months of initial surgery, an assessment of the predictive value of AgNORs can be obtained more quickly in canine tumours than for comparable human neoplasms.

Application of the AgNOR method to cell imprints of lymphoid tissue

The argyrophil (AgNOR) staining technique for nucleolar organizer regions was applied to both cell imprint preparations and 3 microns sections of 40 specimens of lymphoid tissue (10 normal tonsil, 10 reactive follicular hyperplasia, and 10 low-grade and 10 high-grade non-Hodgkin's lymphomas). The mean AgNOR count per nucleus was higher for imprint preparations than for 3 microns sections for each group of specimens (P less than 0.01). The difference was particularly evident for specimens with high AgNOR counts, that is, the high-grade non-Hodgkin's lymphomas (pooled mean AgNOR count/cell 16.3 for imprints as opposed to 6.0 for 3 microns sections, P less than 0.0001). Furthermore, individual AgNOR dots were much more readily discerned in cell imprints than in sections, and this appears to be the method of choice if pathologists wish to at least approach absolute rather than relative AgNOR counts.

Correlation between NOR sizes and numbers in non-Hodgkin's lymphomas

A series of 36 cases of non-Hodgkin's lymphomas (NHL) has been studied by means of the argyrophil (AgNOR) method for nuclear organizer regions (NORs). Morphometric analysis of highly magnified photographic images of light microscope preparations of the AgNORs was performed by means of an interactive image analysis system. It was observed that in the low-grade specimens (where NORs are less frequent than in those of high-grade histology), the AgNOR sites were highly significantly (P less than 0.001) larger than in high-grade NHL. In the low-grade lymphomas, the AgNOR maximum diameter (Dmax) ranged from 0.7 to 1.7 micron 2 (mean 1.11 micron 2) and area ranged from 0.48 to 1.99 micron 2 (mean 1.11 micron 2). In contrast, in the high-grade specimens, Dmax was from 0.33 to 0.51 micron (mean 0.41 micron) and the area ranged from 0.082 to 0.19 micron 2 (mean 0.13 micron 2). Thus, a well-defined inverse relationship was observed between AgNOR numbers and their sizes. There was total separation between low- and high-grade values in this series. This light microscope technique offers some advantages over ultrastructural morphometry of interphase NORs (fibrillar centres).

Salivary gland tumours studied by means of the AgNOR technique

Difficulty is sometimes encountered in distinguishing between pleomorphic adenoma, adenoid cystic carcinoma and adenocarcinoma, especially in small biopsies from salivary glands. The argyrophil (AgNOR) staining technique for nucleolar organizer regions (NORs) has been applied to a series of benign and malignant salivary gland tumours. We studied 35 salivary gland tumours, 13 benign and 22 malignant. In all specimens clearly defined silver-stained intranuclear AgNOR dots were visible. The differences between the numbers of AgNORs in the benign and malignant groups, notably pleomorphic adenomas, adenoid cystic carcinoma and adenocarcinoma, were highly significant. In view of this difference we propose that the AgNOR staining technique is of diagnostic help in distinguishing between these salivary gland tumours.

Coulter Plus IV leukocyte volume analysis instrument: sensitivity of blast identification in peripheral blood

Images

Nucleolar organiser regions in normal, cirrhotic, and carcinomatous livers

A series of 54 liver biopsy specimens was studied by means of the argyrophil (AgNOR) technique for nucleolar organiser region (NOR)-associated proteins. These included normal livers and livers affected by chronic active hepatitis, cirrhosis, hepatocellular carcinoma and adenoma. Four of the cases of cirrhosis showed liver cell dysplasia. The mean numbers of NOR sites in normal, cirrhotic, and carcinomatous livers were significantly different: adenoma had similar mean counts to those in chronic active hepatitis (CAH). There was no overlap between the ranges of NOR counts in normal, cirrhotic, and malignant liver specimens. Where cirrhosis and hepatocellular carcinoma were present in the same specimen, the AgNOR counts were higher in the carcinomatous than cirrhotic areas. To investigate the prospective value of the method a further seven biopsy specimens were studied; in these it had not been possible to decide on a diagnosis between normality and cirrhosis or cirrhosis and hepatocellular carcinoma. In all seven specimens a repeat biopsy or necropsy gave results as predicted by AgNOR staining. It is therefore proposed that quantitation of staining for NOR-associated proteins is a diagnostically useful method in liver disease.