Unfortunately, your positive tissue control is not a control for your test
material! So you should disregard the results.
Tissue controls should be fixed and processed in the same manner as the test
In our experience calretinin is one of the markers that does not respond
well to alcohol fixation.
Other markers used for the differentiation of mesothelioma vs
adenocarcinoma, e.g. CEA, EMA and the epithelial antigen (BER-EP4) also do
not like alcohol fixation. Too late now since the specimen was received in
cytolyte, but we always fixed our cytology cell blocks in NBF, so our
standard controls were appropriate. You could try to obtain some fresh
positive tissues and fix them in cytolyte, then re-optimize your IHC
protocols to the new fixation conditions. You will then have some
appropriate IHC controls for your cell blocks.
Ex Technical Specialist in IHC now just an old retired guy.
----- Original Message -----
From: "Cindy DuBois"
Sent: Monday, May 12, 2003 6:06 PM
> From: Cindy/Rick DuBois
> Date: Wed, 7 May 2003 09:58:50 -0700 (PDT)
> To: firstname.lastname@example.org
> Subject: Calretinin
> Our docs have noticed that our Calretinin does not stain on cell blocks.
> These specimens are initially received in cytolyte (alcohol based
> a cell block is prepared and processed in the tissue processor with the
> of the tissue.
> The control we are using stains positively and is a mesothelioma from the
> lung (formalin fixed tissue).
> Any suggestions on how to get the cell blocks to stain? Any help would be
> greatly appreciated.
> Cindy DuBois HT, ASCP
> Delta Pathology Assoc.
> Stockton, CA
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