STANDARDIZED AGNOR STAINING METHOD FOR FO RMALIN-FIXED AND PARAFFIN-EMBEDDED MATERIAL

Visualization of proteins associated with nucleolar organizer regions proteins (AgNORs) on formalin-fixed and paraffin-embedded archival tis sues is substantially improved after application of wet autoclave pret reatment. Silver staining results are comparable to those obtained on tissues processed in alcoholbased fixatives, illustrating AgNORs as su bstructures of the nucleoli without any staining artefacts. A highly r eproducible staining quality was achieved irrespective of tissue origi n or duration of formalin fixation. As a result of this novel and simp le method, the grounds have been prepared for standardized AgNOR quant ification on archival material.