The evaluation of argyrophilic nucleolar organizing region proteins in fine-needle aspiration samples of thyroid.

Argyrophilic nucleolar organizing region associated proteins (AgNORs) have been shown to be of interest in a variety of different diseases including thyroid disorders. Our aim was to distinguish benign thyroid lesions from papillary thyroid carcinoma (PTC) via AgNOR count and with a new approach, via AgNOR surface area/total nuclear surface area (NORa/TNa) proportions in the nuclei on fine-needle aspiration (FNA) materials. Thirty patients (eight men and 22 women) whose FNA was compatible with benign lesion and 26 patients (eight men and 18 women) whose FNA was compatible with PTC were included in the study. Fine-needle aspiration materials were stained for AgNOR detection according to a specific protocol. One hundred nuclei per individual have been evaluated, and AgNOR number and NORa/TNa proportions of individual cells were measured and calculated by using a computer program. Patients with PTC had significantly (p<0.001) higher AgNOR count (4.6 ± 1.2%) than in the patients with benign lesions (2.0 ± 0.5%). Additionally, patients with PTC had significantly (p<0.001) higher NORa/TNa (13.4 ± 2.4) than in the patients with benign lesion (5.7 ± 1.0). Modified method of AgNOR staining is an easy and reliable method for evaluating proliferation activity of cells in malignant and benign thyroid lesions and it may contribute to routine cytopathology in inconclusive situations.