Expression marking of nucleolar organising regions (NORs) is a modern quantitative diagnostic method applied more widely in evaluation of proliferating activity of tumour cells. A particular interest has been observed since 1986, i.e., since a report by Ploton on a simple colloid method of one-stage protein silverstaining. This allowed a quantitative evaluation of the regions on light microscopy. The present study describes application of marking of argyrophil granules (Ag-NORs) in different tumours and precancerous stages mainly to differentiate borderline lesions. Particular emphasis is paid to the use of the granulation marking in diagnosing small and non-small cell lung carcinoma. The study presents a number of controversies on dependence of Ag-NOR expression on the histological type, clinical stage and tumour mass doubling time as well as views on little usefulness of Ag-NORs in differentiating particular types of carcinomas. Alternating study methods of granules in the cell nucleus from tissue and cytological material, the application of computer analysis and Ag-NOR method assisted by immunohistochemical techniques are also discussed.

Keywords: nucleolar organiser regions, lung cancer