Prognostic value of AgNOR counting

The prognostic significance of the argyrophilic nucleolar organizer regions (AgNORs) in tumour pathology is still a matter of debate. A prospective study was performed in a series of renal cell carcinomas to clarify the prognostic value of AgNOR counting. Sections from 21 renal cell carcinomas were stained in 1990 with the method of Ploton. Black dots within the nucleus from 200 tumour cells were counted: the mean AgNOR count for the whole series was 6.13, the median 5.94 and the SD 1.78. Patients were then followed up for at least 6 years or to death: at the time of the survival analysis (June 1996), 13 patients were alive without evidence of recurrence or metastasis, 6 had died of the disease and 2 of myocardial infarction. All the patients with 5.94 AgNORs per cell or fewer were alive at 6-year follow-up, while only 60% of patients with more than 5.94 AgNORs per cell survived (p=0.01). In the multivariate analysis, only AgNOR count (p=0.015) retained an independent prognostic significance. With the limitation due to the small number of cases, this prospective study clearly indicates that AgNOR count has a significant prognostic role, at least in renal cell carcinoma.