AgNOR quantity in needle biopsy specimens of prostatic adenocarcinomas: correlation with proliferation state, Gleason score, clinical stage, and DNA content

Aims-To define the relation between the quantity of silver stained nucleolar organiser regions (AgNORs) and histological grade, clinical stage, DNA content, and MIB-1 immunostaining in needle biopsy specimens of prostatic adenocarcinomas.Methods-Histological grade was determined according to the Gleason system. AgNOR quantity, DNA content and MIB-1 immunostaining were evaluated by image cytometry on routine histological sections stained with silver, Feulgen reaction and MIB-1 antibody, respectively.Results-The mean AgNOR area increased with increasing Gleason score. A significant difference was found in the AgNOR values between low, intermediate and high grade tumours. Patients with clinically localised tumour (stages A and B) had lower AgNOR values than patients with advanced disease (stages C and D), but the difference in the mean AgNOR values between the two groups was not statistically significant. Non-diploid tumours had a significantly higher mean (SD) AgNOR area than diploid tumours (3.68 (1.04) mum(2)v 2.73 (0.60) mum(2), respectively), while no significant difference was observed in the mean AgNOR values between aneuploid and tetraploid tumours (3.68 (1.04) mum(2)v 3.70 (1.05) mum(2)). When AgNOR and MIB-1-PI values were compared using linear regression analysis, a highly significant correlation was found.Conclusions-These data demonstrate that AgNOR quantity reflects the proliferative potential of prostatic adenocarcinomas, and is significantly related to histological grade and DNA content. The ease of application on routine sections, maintaining the morphological integrity of the tissue, the ability to evaluate selected histological areas of limited size and objective quantification by image cytometry make the AgNOR method particularly suitable for cell kinetic analysis in prostatic needle biopsy specimens.

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.

Evaluation of three different AgNOR counting methods in advanced carcinoma of the prostate

We applied the silver staining of nucleolar organizer regions (AgNOR) technique to the pretreatment biopsies of 50 cases of advanced prostate cancer. Three different counting methods were utilized in the enumeration of AgNORs. All methods yielded statistically significant differences of mean AgNOR counts of groups defined by high and low WHO, and by Gleason grades. However, there was overlap among groups, and further analysis of counts by grouping of patients according to their stage, response to treatment, and prognosis was not conclusive. Replicate counts were performed in 10 cases. While intraobserver reproducibility was high by all methods, only the second counting method yielded nonsignificant interobserver variability. There was a significant intratumoral heterogeneity of AgNOR scores. Lack of technical standardization, low reproducibility, and lack of correlation with prognosis limit the use of AgNOR counts in advanced carcinoma of the prostate.

Progressive activity in latent prostate carcinoma defined by argyrophilic staining of the nucleolar organizer regions (AgNOR)

Argyrophilic staining of the nucleolar organizer regions (AgNOR) was studied in 30 cases of benign prostatic hyperplasias (BPH), 17 cases of latent prostate carcinomas, 50 cases of clinical carcinomas and seven cases of metastatic lesions from prostate carcinomas. The criteria for these comparisons were the number of positive-staining dots per nucleus, the area of the dots, and a relative score determined by multiplying the number of positive-staining dots in the nuclei by the areas of the dots. Overall, there were no significant differences in these three parameters between BPH and latent carcinomas. Among latent carcinomas, however, significantly higher AgNOR scores were observed for infiltrative lesions than for non-infiltrative lesions. AgNOR dot number, area and score increased as tumors became less differentiated, with no significant differences detected in metastatic versus non-metastatic carcinomas. These results suggest that some latent tumors are similar in biological behavior, such as cell proliferation, to clinical carcinoma.