Although there are many common themes in cancer, such as loss of responsiveness to growth signals with a resultant ability to grow unchecked. Other common capabilities of cancer cells include evasion of programmed cell death (apoptosis), inducing the surrounding tissue to provide a blood supply (angiogenesis), evading the immune system, and invading the blood or lymphatic systems to travel elsewhere in the body and take up shop in other organs, such as liver, lung, or bone. Although there are, again, common molecular themes by which cancers do this, individual cancers acquire these necessary (to the cancer) abilities by many different ways.
Even cancers arising from the same cell type can be quite different. For instance, the breast cancer that killed my mother-in-law was a rare spindle cell variant, which is quite different from the much more common invasive ductal carcinoma that is estrogen and progesterone receptor positive. Indeed, even within individual cancers, different populations of cells can be quite different.