Quantitative evaluation of AgNORs in bone tumours

Aims: Primary tumours of bone present a significant diagnostic and therapeutic challenge at times. Silver stained nucleolar organiser regions (AgNORs) have been widely used in a variety of tissues but with a limited study on bone tumours. Our study was aimed at the evaluation of AgNOR count in various neoplastic lesions of bone. Methods: One hundred biopsies of bone lesions were included in this study. Five samples of foetal lumbar vertebrae obtained from foetal autopsies were taken as control. The study included 58 males and 42 females with age ranging from 5 to 70 years. Fifty-two cases were malignant while 48 were benign in nature. Silver staining for nuclear organiser regions was performed according to one-step silver staining technique in these cases. NORs seen as black dots were counted in the nuclei of 100 cells. Results: Our study revealed that the mean count was highest in malignant lesions (4.00+/-0.69) compared with benign lesions (2.16+/-0.43) and normal bone (1.32+/-0.14). Statistically, the AgNOR count showed a significant difference (P<0.001) in all these lesions. Conclusions: The results of the current study revealed that malignant lesions had a greater mean AgNOR count than benign tumours and the normal bone. Thus, quantification of AgNORs strongly correlates with the type as well as aggressiveness of the bone tumour and is diagnostically useful in tumour differentiation.