Viruses and bacteria evolve much faster than cancer, because they: * Use horizontal genetic exchange, so different evolutionary branches can share features. Th

Viruses and bacteria evolve much faster than cancer, because they: * Use horizontal genetic exchange, so different evolutionary branches can share features. This increases evolutionary speed exponentially. * Evolve over a much larger eco-system, whereas cancer has to evolve "from scratch" in each individual over a relatively short time-span. Thus, I think cancer should be a much easier problem, from the evolutionary perspective, than bacteria and viruses.