In my experience Cyclin D1 has been one of the more difficult (or should I
say "frustrating") proteins to demonstrate in formalin-fixed, paraffin-
embedded tissue.

I agree with Keith Miller's previous comments.  We also use DAKO's high pH
target retrieval solution (10' in a steamer followed by a 10' cool-down in
a pan of running cold tap water, then 2 - 5' washes in PBS) along with
their mAb (clone DCS-6) at a dilution of 1:200 for 30' with LSAB+ detection.

We recently stained sections of a  mantle cell lymphoma from another
hospital and obtained spectacular immunoreactivity.  It's interesting to
note that the immunoreactivity (for a variety of antigens) on tissues from
this hospital is usually weaker that what we can obtain on our own tissue.
In addition, I haven't good luck with tissue fixed in B5.

R. Cartun