Understanding Cancer from an Evolutionary Perspective
All living things are constantly evolving, and the various cells of living things are evolving too; the essence of evolution is change in a life form's adaptability to the environment. Cancer cells are no exception. Although evolutionary reversal does occur, just as humans cannot revert to our ancestor Australopithecus, cancer cells cannot revert to normal cells—because both genomes have changed greatly.Thus theories advocating persuading cancer cells to surrender and convert them into normal cells are, at present, fantasy; those advocating this view can be said to know nothing of basic biology. Anyone with a little biological common sense knows such views are nonsense. Unfortunately, many lacking that common sense still believe this error.Once cancer cells arise in a multicellular organism, they, like other cells, strive to evolve stronger ability to adapt to the environment (both the internal body environment and the natural environment) and grow. This is essentially no different from our human ancestors evolving upright walking and tool use—only thus can we survive in the environment.By evolutionary theory, evolution in nature is mostly achieved through natural selection. But once humans grasped the general laws of biological evolution, some evolution came through artificial selection. For example, we humans domesticated many crops and animals; their evolution occurred through artificial selection. Farmers pick the best soybean seeds to grow high-yield, good-tasting, nutritious soybeans—this domestication is a form of artificial selection.In treating cancer, we are in fact inadvertently performing artificial selection on cancer cells. Through various anti-cancer means we kill cancer cells, driving them to evolve stronger survival ability—to escape the devastating blows of our medical means, survive, and keep dividing, producing ever-stronger offspring, until our current methods can no longer control them and treatment fails. This is the fate of many cancer patients.Thus for patients with highly aggressive cancer, whether treatment is beneficial or harmful is hard to say. In many patients, treatment promoted cancer-cell evolution, selecting stronger-surviving offspring, so their cancer progressed faster than before treatment.COVID-19 is a good example here. Continuously mutating SARS-CoV-2 grows more transmissible, and our efforts to block it accelerated viral mutation. But for the virus alone, not all this mutation is bad, because virulence is weakening.Cancer cells differ. Once they evolve stronger offspring inside us, their destruction of the organism grows. For tumors are space-occupying lesions, unlike viral and bacterial diseases; the larger and faster-growing the tumor, the greater its destruction.Given the ubiquity of evolution, humanity's struggle against disease seems endless. Antibiotics once made us think we could eliminate infectious disease. In 1969, the U.S. Secretary of Health, Education, and Welfare confidently said it was time to "close the book on infectious disease," because in developed countries most bacterial diseases were suppressed. Half a century later, that statement sounds absurdly arrogant.In that era, gonorrhea and syphilis were also curbed by antibiotics, directly fueling the Western sexual revolution. But as we know, today the bacteria causing tuberculosis and syphilis are staging a comeback, having evolved resistance to penicillin, erythromycin, vancomycin, and other antibiotics that once defeated them; humanity faces a new crisis. Lethal or carcinogenic pathogens like Staphylococcus aureus and Helicobacter pylori have also evolved superb drug resistance, and HIV shows growing resistance to anti-AIDS drugs.Cancer cells evolving within us face the same situation. Some biopharmaceutical companies claim they are close to vaccines or drugs that prevent and cure cancer, but we need only look at immune evasion by SARS-CoV-2 variants to imagine cancer cells doing the same. Thus the dream of one day permanently and completely eliminating cancer is wishful thinking.If we understand cancer from an evolutionary perspective, our attitude may become more rational. When cancer reaches an obviously incurable stage, avoiding driving cancer cells to evolve stronger offspring may help the patient more. Late-stage cancer patients who abandon aggressive regimens for gentle symptomatic care often survive longer and with better quality of life.If we can help patients specifically improve the internal environment favorable to cancer—helping them quit smoking, drinking, craving pickled foods, and staying up late, and reducing toxic stress and environmental pollution—we can further slow progression.After all, malignant transformation is the body's adaptive response to the environment; long-term adverse stimulation causes intracellular mutations. These proliferating mutated cells may initially aim only to heal wounds; if we weaken environmental stimulation, cancer-cell proliferation slows, even stops.By holism, abandoning fantasies of curing late-stage cancer and globally adjusting the patient's conditions, reducing complications, can in theory improve quality of life, drive cancer cells into (or close to) dormancy, slow progression, and prolong life. This approach may be more valuable than endless new technologies and miracle cures.