Sequential demonstration of antigens and AgNORs in frozen and paraffin sections

A technique has been designed which enables the sequential demonstration of nucleolar organizer regions (NORs) and various antigens, in both frozen and paraffin wax‐embedded sections. The NORs were demonstrated by the standard argyrophil (AgNOR) method and the antigens were shown by either immunoperoxidase (PAP) or immunoalkaline phosphatase (alkaline phosphatase–anti‐alkaline phosphatase or avidin–biotin–alkaline phosphatase) methodology. Clear, reproducible results were obtained and AgNOR sites were enumerated with ease. It is suggested that the sequential method may be of great use in the evaluation of AgNOR numbers in neoplasms, where cell populations are heterogeneous. Cell populations may be demarcated with accuracy prior to the counting the AgNORs.