Cells are constantly reproducing in the body. I forgot the exact number (maybe 2-3 years) but each and every cell in the human body gets replaced within a two year window. Take a look at your body now, and two years later, each and every cell will be a new cell. Now the cells don't all change at the same time. Cancer is when cells mutiny inside the body and decide to go off on some tangent.
Will there ever be a cure? I doubt it. Especially if people continue to smoke, drink, eat garbage, and get obese.
How many cancers can be prevented just by people not smoking, drinking, and getting obese? Yet people continue to do these things.
And then there is the coming diabetes epidemic. A person I know who is studying medicine right now says it will be a humungous problem within a generation if there is no cure found soon.