Hi Gayle and All,
           I have been doing GFP here in mouse liver and lung and I have seen expression in adenovially transfected liver, tumor and lung that was fixed in 10 % formalin and routinely paraffin processed. The expression in the live was so nice our pathologist sent it in to a toxicology journal the name escapes me but it got the cover of this journal. I guess I should write this up but I though it was routinely done? The question people ask me is "what did I do different ?"and I say nothing. I fixed for 24 and 72 hours in formalin and processed in a VIP. The sections are deparaffinize to water and coverslip with vectashield with DAPI.  That's all I know, give it a try .

Hope it helps

Jamie Erickson
Genetics Institute
Andover, MA