Demonstration of nucleolar organizer regions in lung carcinoma by silver staining

Relationship between the argyrophilic proteins of the nucleolar organizer region and stage of squamous-cell carcinoma of the lung

Argyrophilic proteins associated with chromosome nucleolar organizer regions (Ag-NOR proteins) were studied in lung squamous-cell carcinoma cells. After routine staining with silver nitrate, the area index and coefficient of variations of Ag-NOR protein were estimated by computer-aided image analysis. The Ag-NOR protein area indexes of tumor cells differed in clinical morphological variants of squamous-cell cancer (differing by T and N parameters, size of the primary node <3 cm or larger, by disease stage, and differentiation degree). Ag-NOR protein variation coefficient can be used for discriminating the tumors by size (<3 cm and larger), presence/absence of metastases, and evaluation of squamous-cell cancer differentiation degree. Ag-NOR protein area index and variation coefficient can be used as additional objective differential diagnostic criteria of clinical and morphological forms of squamous-cell carcinoma of the lung.

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.

Prognostic significance of argyrophilic nucleolar organizer region (AgNOR) in resected non-small cell lung cancer (NSCLC)

The expression of the nucleolar organizer regions (NORs) was quantified in paraffin sections of tumors and lymph node metastasis, by means of digital image analysis, in 75 patients with resected non-small cell lung cancer (NSCLC). Patients were divided in two groups: early stage (stages I and II) and advanced stage (stages IIIa, IIIb and IV). The prognostic significance of AgNOR expression was tested by Cox regression analysis in models controlled for age, sex, vital status, stage and histological type. Tumors at early stages had a lower expression of AgNOR than those at more advanced diseases. The mean values obtained for NORs in advanced disease were almost the same as those in the primary tumors when compared with the corresponding lymph node metastasis (r = 0.90; p < 0.01; linear regression). The prognostic role of AgNOR was significant only for tumors at stages I and II and not for advanced neoplasms (stages IIIa, IIIb and IV). These results encourage the inclusion of AgNOR quantitation in routine material, especially in early lung cancer.

Evaluation of argyrophilic nucleolar organizer regions (AgNORs) in oral carcinomas in relation to human papillomavirus infection and cytokinetics

The numbers of argyrophilic nucleolar organizer regions (AgNORs) were quantified in oral carcinomas (n = 39) with or without human papillomavirus (HPV) infection. The AgNOR counts of the HPV-positive samples (7.15 +/- 2.13) were not significantly (P = 0.09) higher than those of the HPV-negative ones (6.16 +/- 1.89). Furthermore, the lesions infected with multiple HPV types had greater counts than those with HPV type 16/18 infection alone. Significant differences were observed between the mean counts of the poorly (10.50 +/- 0.54), moderately (7.31 +/- 1.07) and well- (5.12 +/- 0.85) differentiated carcinomas. The mean AgNOR numbers in the oral carcinomas at TNM stages III/IV were found to be significantly (P < 0.01) higher than the numbers in corresponding stage II lesions. Cytokinetics of the lesions assessed by the bromodeoxyuridine (Brdu) labelling index (LI%) showed a linear correlation (r = 0.91; P < 0.0001) with their respective mean AgNOR counts.