Why astrobiology gives hope for cancer therapy

Cancer might look like a moving target, but it's not, says ANU astrobiologist and cosmologist Charles Lineweaver, and this fact ought to give hope to cancer researchers looking to find ways to combat cancer.

As reported yesterday, Lineweaver along with Paul Davies, found that cancer cells resemble early forms of multicellular life, and emerge when our more recently evolved regulatory genes are damaged or mutate, allowing more ancient genes to take over.

This novel theory sheds light on many mysteries of cancer, such as how cancer cells are so capable of defending themselves against chemotherapy treatments.

In fact, says Lineweaver, the research suggests that while cancer appears complex, its complexity is limited, and once we understand the genes responsible for its development, then it won't offer too many more surprises.

"Oncologists need some help," Lineweaver told ALS. "They are seeing so much complexity in the genes responsible for cancer that they're throwing up their hands saying 'where in the hell did that come from?' Cancer is complex and it seems to be able to avoid everything I can throw at it.

"Our message is that cancer does have a complexity, but that complexity is limited. There is a ceiling that we're just about to hit.

"The number of genes that can cause cancer are limited. They have evolved very early, and they're very sophisticated. They're very good at surviving. It's no mystery that cancer knows when it's attacked by a chemical, and that it knows how to get rid of it.

"How does it know how to do that? Because we knew how to do that a billion years ago. And the cells have essentially reverted to an earlier stage of only partially differentiated life forms."

This means that cancer isn't necessarily evolving new defence mechanisms from scratch, but calling on ancient defence mechanisms which, once understood, can be countered.

"The reason why a lot of oncologists think it might be a moving target is because when they do genetic sequencing of the progression of cancer in some particular part of the body, they find so many different kinds of oncogenes, and it's just a complicated mess.

"But our model is that although it looks like a complicated mess, it will eventually be resolved into the genes that are involved in each step of cancer, and that all the abilities that cancers have, and that we see as it progresses, are things that are already written in stone, and they will stay written in stone.

"This is precisely because cancer does not evolve in the normal way we understand it. It's only relying on a pre-programmed, pre-existing toolkit that has been suppressed, and when the suppressors are gone, we're seeing the control revert back to that toolkit."

Lineweaver hopes that this big picture understanding of the origins and cause of cancer will help cancer researchers develop new approaches to combating cancer, either by targeting the oncogenes, or by reinstating the natural suppression mechanisms that keep our more ancient genes in check.

The full paper is available online at the Physical Biology site.