Dear Mike,
This is not an easy question to answer becuase there are many
points for each process. The PE-block procedure disadvantages
1. it is time consuming
2. the histograms are in general poor and 30 to 40% can not have %S
evaluated
The PE-block advangtages
1. One can make a better correlation with tumor content ( H&E
staining) and DNA
histogram result. (ie correct for sampling artifact). One could
also do tumor
enrichment if you can find a good pathologist who will work with you.
2. Easy to relate flow data to other factors such as steroid receptors
that is being done
by immunohistochemistry.
Advantages of frozen tissue
1. It is faster and cheaper
2. In general, one obtains better histograms and more tissues can have %S
analysis done.
Disadvantages of frozen tissue:
1. one might have sampling artifacts which are not easy to document.
2. Most outside hospitals do not save the frozen tissue and would
rather send
the PE block.
Final Comment: In all of our studies, there does not seem to be a
difference in the ploidy and cell cycle distributions by either method.
One might be able to use PE block material to due two color analysis as
described in a recent article in Cytometry ( 24,p260,1996). In my
opinion, it is hard to get good data from two color analysis on fresh
tissue. Try both procedures and see what you like the best.
Hope that this helps.
Dr. Tim Kute email: tkute@bgsm.edu
Associate Professor in Pathology Tel#: 910-716-2950
Wake Forest Univ-Bowman Gray School of Medicine Fax#:910-716-7595
Medical Center Blvd
Winston-Salem, NC 27157-1072