C.O.
first thing you need to do is pick one. Then find a foundation that you can volunteer at and then prove yourself to get picked up as an employee.
There are so many types of cancer - so you really need to find the "one" that calls to you.
If you can't have children of your own - fostering and adoption may work for you as well - contact your local child protection services
http://local.yahoo.com/details?id=13600181&stx=child+...
and find out how to get started, what is required, what you need to do, etc. and then make a decision.
Your husband needs to be on board with this as well. So you need to get all your ducks in a row and have the information to make a decision.
Once you find out "how things work" - you might be able to start your own foundation in the future. However, you need facts and information. Don't just "google" them - go directly to the source and have a list of questions - who, what, where, when, why, how much, how long, requirements, etc.
here is a list of charitable organizations. this might help you as well.
http://www.guidestar.org/?gclid=CL6Dm4_e0rQCFU-d4Aodd1QApA
good luck