But there are other ways. One way is to follow the thread of research opened up by William B. Coley who developed Coley's Toxins, a cocktail of bacterial toxins that sparked the body's own defense mechanisms and in many cases, caused cancer tumors to turn to jelly within days and start being reabsorbed by the body. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1888599/ has more about him.
Or the way of genome therapy where researchers are studying the active genomes in both healthy and sick (or cancerous) cells to understand what knobs and buttons exist in the human organism that we might be able to adjust by means of various therapies, sometimes even benign ones. There is evidence that one of the many hundred subtypes of cancer will respond to everyday blood pressure medication. This is a relatively benign drug that, in the right conditions, will kill cancer cells. Of course, the right conditions include that the patient has certain specific genes. But genomic techniques ca discover these genomic markers and help us sort out the mechanisms by which cells resist attacks from hostile bacteria. The ultimate outcome for cancer would be that your doctor takes a biopsy of the cancer cells, their active genomes are analyzed and this information is used to build a molecular machine that manufacture a custom drug that will cure your cancer.
Look at the molecular machinery of the Polymerase Chain Reaction which makes copies of DNA molecules https://en.wikipedia.org/wiki/Polymerase_chain_reaction
And there is Reverse Transcription which converts RNA molecules to DNA molecules https://en.wikipedia.org/wiki/Reverse_transcription_polymera...
Not to mention the Ribosome which is the molecular machine in your cells which manufactures protein molecules https://en.wikipedia.org/wiki/Ribosome