[Histonet] Breast processing
Rcartun <@t> harthosp.org
Mon Oct 8 15:07:35 CDT 2012
My personal experience is that formalin fixation for 72 hours (and longer) does not affect immunoreactivity for ER, PR, and HER2 protein overexpression as long as the tissue does not "dry-out" before being placed in formalin and "thin" (2-3 mm) sections are submitted for fixation and histologic processing. There have been several articles published recently that support this observation including one from 2002 (5 years before the ASCO/CAP guidelines were published!). In fact, I would like someone to show me where the scientific evidence is for supporting these "guidelines". Remember, these are "guidelines"; you are permitted to experiment, validate, and write-up your own fixation policy for your institution.
Arber D: Effect of prolonged formalin fixation on the immunohistochemical reactivity of breast markers. Appl Immunohistochem Mol Morphol 2002;10:183-186.
Ibarra JA, Rogers LW: Fixation time does not affect expression of HER2/neu. Am J Clin Pathol 2012;134:594-596.
Tong LC, Nelson N, Tsourigiannis J, et al.: The effect of prolonged fixation on the IHC evaluation of ER, PR, and HER2 expression in invasive breast cancer: a prospective study. Am J Surg Pathol 2011;35:545-552.
I apologize to the authors of the other studies, but I had immediate access to these references since I gave a lecture on this topic today.
Richard W. Cartun, MS, PhD
Director, Histology & Immunopathology
Director, Biospecimen Collection Programs
Assistant Director, Anatomic Pathology
80 Seymour Street
Hartford, CT 06102
(860) 545-2204 Fax
>>> "Gudrun Lang" <gu.lang <@t> gmx.at> 10/8/2012 3:31 PM >>>
Is there any evidence, that NBF-fixation for 72 hours alters Her2 staining, so that there's a diagnostic difference (pos./neg.)? publications with data?
I have the feeling, that there is a mythos of overfixation. Anybody else ...?
I saw turning up and down of Her2 results due to non-standardized staining-protocols.
But I think a protocol, that fits to a 48 hours-fixed tissue fits also to 72 hours.
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