In my experience, freezing the tissue prior to histological processing can reduce or even eliminate immunoreactivity for ER and PR.  We did a small study years ago where we compared the immunoreactivity for ER and PR on the tissue used for the frozen section diagnosis and tissue that was not frozen.  We saw several "false negatives".  We always recommend using a "non-frozen" block of tissue for IHC, but, as you already know, this is not always possible.  Please note that freezing can also affect S-100 immunoreactivity; this can result in a "false negative" when examining sentinel lymph nodes for metastatic malignant melanoma.

R. Cartun


>>> anita dudley  01/23/02 11:42PM >>>
does anyone have any experience staining tissue for er-pr that has been 
previously frozen?  we had a small bx that was frozen in the or then 
processed for permanent sections. the paths thought it should be positive 
but they were both negative.  does anyone have any data on this?  thanks so 
much, everyone have a nice day.

anita dudley  providence hosp.  mobile alabama

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