Can Apache proxy interfere incoming request manipulate it forward and then do the same on response using mod_perl?

I have Apache that used as proxy server that forward incoming requests
to application server, based on Some rules , all working fine .
Now this incoming request , needs to be changed before they reaching
to the application server And when they returning back from the
application server the massage needs to be changed again and send the
response.
The manipulation in the proxy server done with perl script , so
mod_perl needs to be installed .
But my concern is how can it be done if it can be done .
Thanks