What are the possible causes of cytoplasmic staining when doing
immunoperoxidase Estrogen Receptor staining? The controls show nice
crisp nuclear staining and no background staining. The specimen was a
needle biopsy sent from the X-ray Department. Is it possible to get
antigen diffusion from the nucleus to the cytoplasm due to a delay in
fixation or high antigen level?

Thanks,
Dan
Windsor Regional Hospital,
Windsor, Ontario, Canada.