Cancer is found across the animal kingdom from invertebrates to vertebrates. Animals evolved tumor-suppressing strategies, both molecular and behavioral, to overcome the negative effects of cancer, and it may be possible to exploit the solutions conferred by natural selection.

“The organ-specific variation in cancer incidence has previously been attributed to external factors, such as smoking and ultraviolet light exposure, or to internal factors, such as how often cells must divide in an organ. We propose that looking only at external or internal factors does not explain all the observed organ-specific differences. We suggest that additional factors, such as the importance of organs to the host survival and reproduction, could contribute to cancer resistance or susceptibility,” said Dr Ujvari.

It may be beneficial to consider organs as distinct but connected ecosystems, with different susceptibility to malignant transformation. Dr Ujvari added that this viewpoint, although so far overlooked, is important to consider: “we would like to initiate scientific debates and to encourage the development of novel theoretical and empirical approaches that use evolutionary ecology theories and toolsets.”

Co-author Frederic Thomas, an evolutionary biologist at the Center for Ecological and Evolutionary Cancer Research in Montpellier, France, said that the organs essential for survival reproduction, such as the heart, brain, or uterus, may be naturally protected against cancer.

Drs Thomas and Ujvari are running a long-term experiment with mice to measure the accumulation of cancerous and precancerous mutations inside different organs.

Carl Freter, MD, professor of internal medicine and director of the division of hematology and oncology at Saint Louis University in Missouri, said this is a fascinating approach with significant merit. “We know that there are marked organ specific differences in susceptibility to cancers and certain types of cancers. This could open up a whole new area of oncology,” Dr Freter told Cancer Therapy Advisor.

According to Dr Freter, the notion that there are evolutionarily conferred differences between organ cancer susceptibility in terms of microenvironment and genetic expression could indeed lead to new therapeutic approaches.

But whatever the direct consequences, it is unquestionably important to attempt to integrate evolutionary logic into the genetic, cellular, and causal aspects of cancer.

Reference

  1. Thomas F, Nesse R, Gatenby R, et al. Evolutionary ecology of organs: a missing link in cancer development? Trends Cancer Res. 2016 Aug 9. doi: 10.1016/j.trecan.2016.06.009 [Epub ahead of print]