Challenging the standard model of cancer

New atavistic model shows role of ancient genes in the spread of cancer

May 20, 2021

In spite of decades of research, cancer remains an enigma. Conventional wisdom holds that cancer is driven by random mutations that create aberrant cells that run amok in the body.  

In a new paper published this week in the journal BioEssays, researchers in Arizona and Australia challenge this model by proposing that cancer is a type of genetic throwback that progresses via a series of reversions to ancestral forms of life. In contrast with the conventional model, the distinctive capabilities of cancer cells are not primarily generated by mutations, the researchers claim, but are preexistent and latent in normal cells.  man sitting at desk Paul Davies pictured in his office. Download Full Image

Regents Professor Paul Davies, director of Arizona State University’s Beyond Center for Fundamental Concepts in Science, and Kimberly Bussey, cancer geneticist and bioinformatician from the Precision Medicine Program at Midwestern University in Glendale, Arizona, teamed up with Charles Lineweaver and Anneke Blackburn at the Australian National University (ANU) in Canberra, Australia, to refine what they call the serial atavism model (SAM) of cancer. This model suggests that cancer occurs through multiple steps that resurrect ancient cellular functions. 

Such functions are retained by evolution for specific purposes such as embryo development and wound healing and are usually turned off in the adult form of complex organisms. But they can be turned back on if something compromises the organism’s regulatory controls. It is the resulting resurrection steps, or atavistic reversions, that are mostly responsible for the ability of cancer cells to survive, proliferate, resist therapy and metastasize, the researchers said. 

Davies and Bussey are also members of ASU’s Arizona Cancer Evolution Center, which seeks to understand cancer not just in humans, but across all complex species, in the light of evolutionary processes. 

“Cancer research has been transformed in recent years by comparing genetic sequences across thousands of species to determine gene ages,” Davies said.

Just as geologists can date rock strata, so geneticists can date genes, a technique known as phylostratigraphy. 

”The atavistic model predicts that the genes needed for cancer’s abilities are mostly ancient — in some cases little changed over billions of years,” Davies said. 

Lineweaver explained, “In biology, nothing makes sense except in the light of evolution, and in the case of cancer nothing makes sense except in the light of the deep evolutionary changes that occurred as we became multicellular organisms.” 

“The atavistic model of cancer has gained increasing traction around the world,” Bussey said. “In part, this is because it makes many predictions that can be tested by phylostratigraphy, unlike the conventional somatic mutation theory.” 

Blackburn, a cancer biologist in ANU’s John Curtin School of Medical Research, agreed. 

“Appreciation of the importance of gene ages is growing among oncologists and cancer biologists,” she said. “Now we need to use this insight to develop novel therapeutic strategies. A better understanding of cancer can lead to better therapeutic outcomes.”

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Sun Devil Baseball Set for Penultimate Season Series at USC

May 20, 2021


The #25 Sun Devil Baseball program hits the road for the final time of the regular season this weekend, heading west for a three-game Pac-12 series against USC in Los Angeles. The series will get underway on Friday at 6 p.m. AZT, followed by a 3 p.m. start time on Saturday and wrapping up with a Noon first pitch on Sunday. All three games will be broadcast by the Pac-12 Network. Download Full Image