CAS can evaluate your network's vulnerability and put all of the factors of protection in place.  Anti-virus software is no longer the main component of a secure network.  Data must be inspected and filtered as soon as it enters the network regardless of the sources (web, e-mail, USB device, CD/DVD, documents, etc).  It is no longer sufficient to have a security solution in place that doesn't provide constant monitoring to ensure proper actions are taken to protect the company.