Hi there:
I used DAKO CSA system (K1500) on mouse FFPE tissue with ARK kit (K3954) 
since my primary antibody is from mouse. The antigen should localize in 
nucleus. But the nucleus that positively stained seems "expanded". What I 
mean is the nucleus is in the center and little more area around nucleus is 
also stained. I called DAKO guy and was told most likely my antigen leaked 
out of nucleus because of inappropriate fixation. The way I did is fixed the 
tissue (small) in 10% neutral buffered formalin for 16 hours before 
dehydration. Could anybody tell me what reasons can cause antigen leak out 
of nucleus and what fixation I should follow?
Any suggestion or comment is highly appreciated.

Thanks.
Carol Chang

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