When I first learn cancer biology, my teacher told me that cancer is usually caused by the loss of tumor suppressor , which is like you loss your brake.
After it losses the suppressor, it tends to have more mutation, so it has chance to mutate other suppressor and oncogene in a direction that can benefit cancer cells.
(However, on the other hand, once you have more mutation, it means you have more chance to present those mutated peptides to the surface of the cells, which would cause strong immune response.)
I know many cancers have low mutation load. How do they achieve this low mutation load with the loss of tumor suppressor?