Re: [Histonet] Old paraffin sections

From:"Jackie M O'Connor"

Many antigens will deteriorate on old cut paraffin sections - well 
documented instances are CD31, and Ki67.  I would guess PCNA would be the 

"Till, Renee"  
Sent by:
04/17/2007 07:31 AM


[Histonet] Old paraffin sections

What is your opinion of the effectiveness of IHC on paraffin sections that
have not been recently cut? 

I have been trying to do a PCNA on some liver paraffin sections. I was 
the paraffin blocks, but also some slides boxes of previously cut slides 
1 to 2 years old. Do you think this could greatly effect the staining of 
slides? I don't normally do too much liver staining, so I had begun 
my mammary gland PCNA protocol to the livers, when I was given a protocol
this group had previously used in several of their papers. When I try to
duplicate this protocol, I get faint staining to negative slides. I have
tried everything I can think of. Remaking solutions, using a newer 
in case the other had been frozen too long (though I've never had a 
with that before), leaving the DAB on longer, anything that still is 
the protocol. The only thing left I can think of is the age of the 
The only other thing I can think of is that my secondary is from a 
company than theirs, and I can't do anything about that short of ordering 
other and waiting for it. I generally order my secondaries from Jackson 
have never had any problems with them. 


Renee' Till, HT

Research Assistant

Arkansas Children's Nutrition Center

1212 Marshall St./N2021

Little Rock, AR 72202

Lab (501)364-8504

Office Fax (501)364-3161


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