‘How cancer evolves within our bodies’

Book cover

James DeGregori is a Professor in the Department of Biochemistry and Molecular Genetics at the University of Colorado School of Medicine and the Deputy Director of the University of Colorado Cancer Center.  His lab studies the evolution of cancer, in the context of their Adaptive Oncogenesis model, with a focus on how aging and other insults influence cancer initiation. His lab has developed this cancer model based on classic evolutionary principles and substantiated this model by theoretical, experimental, and computational studies. This model is described in his recent book, Adaptive Oncogenesis: A New Understanding of How Cancer Evolves inside Us (Harvard University Press). The following is the introduction to that book. Matt Young will serve as moderator of this thread.

Why do we get diseases like cancer, and why do we get them mostly when we are old? Why do children get cancer? Why do we age? These may seem like existential questions, but there are answers, even if we do not know all of them. If you go to your doctor, you will get proximate explanations, which consider the causes of processes and diseases like aging and cancer within us. You may be told that aging is the result of a lifelong accumulation of damage to your tissues, both from errors that occur as your body maintains itself and from the damaging exposures that we experience during life. Analogously, you will be told that cancer is the result of a lifetime’s accumulation of genetic alterations (mutations) and that the accumulation by chance of a certain set of cancer-promoting mutations explains the increased risk of cancer late in life. Similarly, exposures to carcinogens, such as through smoking, are said to cause cancer by inducing mutations that change normal cells into cancer cells. But the more informative and more useful answers lie in an evolutionary understanding of life history and disease. As the great evolutionary biologist Ernst Mayr said, “No biological problem is solved until both the proximate and the evolutionary causation has been elucidated.”

Cancer is the second leading cause of death in industrialized countries: about 40 percent of people in those countries will develop cancer, and close to half of these individuals will die from their disease. Cancer is largely a disease of old age, with over 90 percent of cancers occurring in individuals over fifty. Other causes of cancer include cigarette smoking, alcohol consumption, sun exposure, pollution exposure, infections, and obesity. The medical and research communities have primarily ascribed associations between aging or exposures and cancer to enhanced mutation accumulation, despite strong evidence challenging such simple relationships.

Mareca americana

Mareca americana – American wigeon making an interesting splash while diving for whatever American wigeons dive for. Walden Ponds, Boulder, Colorado, February, 2018.

Buteo lineatus


Photograph by Tom Gillespie.

Photography contest, Honorable Mention.

 Red-shouldered hawk
Buteo lineatus – red-shouldered hawk (immature), April, 2015, Duluth, Georgia. Mr. Gillespie notes, "For some reason, this little guy decided to try and eat from the sunflower feeder I have on my deck rail."

Can you learn to do science by watching?


Can you learn to do science by watching scientists? I do not know, but Natural History magazine this month ran a short article Of moonwalks and tablecloths, which describes experiments in which people watched videos of other people performing complex activities. The purpose of the experiment was to assess whether people who watched the videos might overestimate their own abilities to perform the complex activities. In particular, the researchers, Michael Kardas and Ed O’Brien of the University of Chicago business school, allowed participants to view a person snatching a tablecloth from under a set of dishes. Those who watched the video 20 times were more confident that they could perform the trick than were those who watched it once.

In other experiments, according to Natural History, people were actually tested on how well they could perform certain (presumably less dangerous) activities, such as throwing darts and tracing an image viewed through a mirror. Those who watched a video several times did not perform better than those who watched it once.

I do not want to belabor this, but I think we may gain insight into the behavior of some of our trolls: They think that if they can watch enough science or read enough science, then suddenly they can understand science or write about science. What they write on this blog gives the lie to that contention.

Avida-ED Active LENS Workshop Applications Being Accepted


There are still spaces for more teams of two each at the 4th annual Avida-ED Active LENS Workshop at the North Carolina A&T University in Greensboro, North Carolina, June 14-16, 2018, so the application deadline is being extended. Travel and expenses will be covered by the workshop sponsors for educators wishing to learn how to use the Avida-ED artificial life program in teaching evolution.

From the flyer:

Avida is a digital evolution software platform used to study evolutionary processes, and harness evolution to solve engineering problems. Avida-ED is a free, user-friendly, browser-based version of Avida developed specifically for educational purposes, with a graphical user interface and visualizations that allow the user to observe evolution in action. (See http://avida-ed.msu.edu/ for more information.) Organisms within this software are self-replicating computer programs, competing for computational resources supplied by the environment. Their replication is imperfect, resulting in mutations in some of their offspring, which may alter the ability of those organisms to make use of their environmental resources. Populations studied over the course of generations therefore display all of the elements necessary for evolution by natural selection: variation, inheritance, selection, and time.

A link to the application is in the flyer.

Disclosure: I was formerly part of the Avida-ED project (2008-2009), and my spouse, Dr. Diane Blackwood, is the current software architect for Avida-ED.