I'm an absolute layman, so I'm more curious here whether I am wrong: So far I've always understood that, however different a cancer may develop, all kinds of cancers have roughly the same cause: Some event corrupts a cell's DNA such that:

a) The corruption cannot be repaired;

b) The cell still survives;

c) The mechanisms that normally regulate cell division are impaired, causing the cell to continually divide.

d) The daughter cells also have DNA corruptions with the same properties.

Of course, depending on the nature of the DNA corruption and on what cells were corrupted, the resulting illnesses may be vastly different, as well as the strategies to combat them. But couldn't you at least look for ways to prevent cancer universally if you somehow address this common cause?