> I was curious as to whether or not anyone else is experiencing a marked
> difference in nonspecific IHC staining between breast core biopsies and
> large pieces of breast.  I am running into alot of nonspecific cytoplasmic
> staining on my breast core biopsies that does not occur on the larger
pieces
> of breast from the same case.  We have attempted different processing
times
> to prevent it but to no avail.   The biggest difference between the
handling
> of the breast Bigs and the breast Bx's is the processing times.  My logic
is
> that the core biopsy should not need the extended processing due to it's
> small size.  I'm at a loss.  Any like experiences or suggestions would be
> appreciated.
>
> Thanx in Advance,
>
> Glen Dawson  BS, HT &  IHC (ASCP)
> Lead IHC Technologist
> Milwaukee, WI

Glen,

Are you using a biotin based detection system? We had a similar problem with
nonspecific staining for several months.   It drove me crazy until we
established that the staining was mainly found in breast cores and was
probably due to biotin since it could be blocked with biotin blocking
reagents. I can't explain why its found in core biopsies and not in larger
pieces of breast. One theory is that because of the small size, core
biopsies are fixed quicker  and this preserves more biotin. Antigen
retrieval definitely aggrevates the problem.

Tom Wells  BSc, ART (CSMLS)
Supervisor
Immunohistochemistry Laboratory
Lions Gate Hospital, North Vancouver
Canada