Andrea,

Funny you should ask about Caspase-3. I have trying to get it to work on 
formalin fixed tissue. It seems to be working ok using our antigen retrieval 
method and at a dilution of 1:500. There seems to be quite a bit of cross 
reactivity with this ab but the scientists that I work with feel that there 
is some darker staining in some cells with may indeed reflect positive 
Caspase 3 activity. I would be happy to discuss this further with you and 
would love to hear how it's going for you. Good Luck!

David Clark
Neuropathology
Oregon Health Sciences University