Both theories—the viral and the physiological aging model—also suggest drug discovery efforts that emphasize simultaneously targeting tumor microenvironments and tumor cell phenotypes.
Improving both cancer prevention and cancer treatment will require consideration of both cells harboring oncogenic mutations and the tissue microenvironment, Dr DeGregori said. That requires lifestyle choices like exercise, healthy diets, and eschewing tobacco use, of course.
But to develop more effective cancer treatments, “we need to move beyond therapies that are highly damaging to normal tissues, like radiation and chemotherapies,” Dr DeGregori added. “We should not be surprised when a more aggressive cancer emerges sometime after therapy: bad cells can thrive in bad environments. Healthy infrastructures favor normal cells, so we should strive to promote healthy tissues for both prevention and during therapies.”
“Most efforts are on the discovery of drugs that target the cancer cells, but we would suggest that greater efforts should be expended in manipulating the tissue microenvironment,” Dr DeGregori said. “Our theory argues that the fitness impact of an oncogenic mutation is entirely dependent on its tissue microenvironment. Thus, we should be able to disfavor cancerous cells by normalizing tissue microenvironments, both for prevention and for treatment. Targeting cancer cells is like trying to solve the drug problem by eliminating drug dealers, without dealing with the underlying social and economic factors.”
For example, chronic inflammation increases with age and promotes many types of cancer, noted Dr Rozhok.
Targeting tumor cell fitness and inhibiting cancer cell proliferation “requires a double approach,” Dr Rozhok reiterated. “Target phenotype and environment in parallel, as both are key to altered cell fitness, based on evolutionary theory.”
The viral theory similarly emphasizes tumor microenvironments. The 2 evolutionary models overlap and are far from mutually-exclusive.
“I believe that the ‘Ewald theory’ on viral origins for many cancers and our theory of Adaptive Oncogenesis are quite compatible, in that viruses can provide the oncogenic hits that can be adaptive on aging or otherwise altered tissue landscapes,” Dr DeGregori told Cancer Therapy Advisor.
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