Prognostic value of argyrophilic nucleolar organizer regions (AgNOR) count in adenoid cystic carcinoma of salivary glands.

A retrospective study was performed on 34 patients with adenoid cystic carcinoma (ACC) to see if quantification of argyrophilic nucleolar organizer regions (AgNOR) was correlated with their prognosis. Mean follow-up period was 113 months. According to detailed clinical data that included tumor recurrences, metastases and patient survival conditions, two groups were classified. Group 1 consisted of 20 live patients without metastases, of whom 16 were free of disease, while group 2 comprised 14 patients with metastases among whom 12 died of tumor. The silver staining technique was applied to paraffin embedded specimens. In each case, 300 nuclei were randomly examined and the mean AgNOR per nucleus was calculated. All patients from group 2 had mean AgNOR counts greater than 4, whereas 65% of patients from group 1 had mean AgNOR counts less than 4. In addition, statistical analysis showed that the pooled mean AgNOR count in group 2 was significantly higher than in group 1 (P < 0.01). The present results suggest that silver staining technique promises to be a useful supplementary method for prognostic evaluation of salivary ACC, and may be performed before planning the treatment.