Rich Cartun can enlighten us here, but in my experience ER/PR is
expressed at many differenct levels in the patient samples, you cannot
just ask is it positive or negative.  As Steve mentioned fixation can
affect the results.  Your control tissue should be fixed and processed as
close to the same as the patient tissue as possible.  Using control
tissue with different levels of ER/PR expression is a really good idea,
sometimes tissue arrays or composits may be necessary.  If your + control
has a very high level of expression and you consider patient material
which  does not stain at that level negative or inadequate you are asking
for trouble.
Patsy

Steve Machin UK wrote:

> Im my experience ER positivity varies greatly with fixation time to
> such an extent that core biopsies ,fixed for a couple of hours, can
> not be used to control breast lumps.
> So make sure the tissue blocks are the same size and fixed for the
> same length of time.
> Also, use three grades of positivity in the control tissue, weak
> moderate and high.  This ensures that the pathologist can esimate how
> well the particular immuno run has worked.
> As for the relationship between ER and PR positivity I am not
> qualified to comment upon it.
>
> Best Wishes
> Steve Machin UK
>
>  --- NAVEEDA FAHEEM KHAN  wrote: > HI
> Histonetters
> > any one in the histaland can solve my problem. we use DAKO ER/PR
> > system for estrogen progestrone receptors in the patients mostly
> > breast specimens. our specimens are fixed in 10% bufferred
> > formalin. the problem is that our control show good positive
> > results but test results are variable. our pathologist says that in
> > most of the cases if Er is negative then PR should also negative
> > this is rare phenomena that pr is positive and er negative if any
> > one can guide me that will be great that how i can convince my
> > pathologist please give me some literature articles also if you
> > have
> > thanks in advance
> > naveeda
> >
> >
> > --
> > Naveeda Arshad
> > Pathology Department
> > Aga Khan university Hospital
> > Karachi
> > Pakistan
> > --
> >
>
> __________________________________________________
> Do You Yahoo!?
> Everything you'll ever need on one web page
> from News and Sport to Email and Music Charts
> http://uk.my.yahoo.com