[Importance of AgNOR analysis in malignant tumors]

For the assessment of proliferative activity of malignant tumors several methods can be used. The method having been used at first has been the determination of mitotic index, playing an important role as a part of various grading systems until now. Besides of DNA cytometry, flow cytometry, determination of bromodeoxyuridine labeling index (BrdUr-LI) and immunohistochemical analysis of proliferation-associated antigens (e.g. Ki-67, PCNA), for several years AgNOR analysis has been used as a new technique, giving reproducible, exact results of proliferative activity of malignant tumors. Valuable information about proliferative activity of cells can be gained already by counting the AgNOR number per nucleus. Moreover the use of digital image analysis provides information about size and distribution of AgNORs. Evidently these data are more important than AgNOR number. In the hands of experienced pathologists and under standardized conditions AgNOR staining and AgNOR quantification are a valuable completion of established methods.