Hmm, interesting approach.
There already are salves that increase your immune system's awareness in a localized area (in general though) that can be used to treat certain kinds of skin cancers.
This is the next logical step.
However, considering how every cancer expresses different proteins on its surface and how cancer is able to quickly adapt (i.e. mutate to not express specific proteins anymore), this sort of treatment would have to be not only individual but also constantly adjusted.
Agayek, not really, you can put pretty much anything in vaccines. If you combine it with something your body attacks, it'll "learn" to also attack the thing you want it to.
This is basically the same way that reactive autoimmune diseases are working:
Bacteria or whatever express certain proteins that are similar to our own cells' proteins. The immune system starts attacking these germs but also anything else with these proteins. And *BAM*, you got yourself a case of reactive arthritis.
Anyway, It's not really a vaccine, it just works on a similar basis.