Nucleolar organizer regions in lymphomas

TLDR

Silver staining of paraffin sections enabled easy enumeration of Ag‑NORs in 90 non‑Hodgkin lymphoma samples, five tonsils, and five reactive nodes. Ag‑NOR counts were significantly higher in high‑grade lymphomas (4.4–6.8 per nucleus) than in low‑grade ones (1–1.5 per nucleus), and Ag‑NORs were often present even where nucleoli were not visible, suggesting the method could be widely applied in tumor histopathology.

Abstract

Abstract Using a silver staining technique, nucleolar organizer region‐associated proteins (Ag‐NORs) have been studied in paraffin sections of 90 non‐Hodgkin's lymphomas, five palatine tonsils and five ‘reactive’ lymph nodes. The method was readily applicable to these preparations and the Ag‐NORs were enumerated with ease. A significant difference was found between the numbers of Ag‐NORs in the nuclei of low‐grade lymphomas (from a mean of 1 to 1·5 per nucleus) and those of high‐grade lymphomas (a mean of 4·4 to 6·8 per nucleus). The Ag‐NOR regions were often observed in nuclei in areas where nucleoli themselves were not visible. It is suggested that this method, previously largely the province of the cytogeneticist, should find widespread applications in the field of tumour histopathology.