Big bang vs clonal sweep
Jack Edwards is a SPARK student that, while doing a degree in Physics at USF, has spent the summer working on an interesting problem in mathematical oncology: Investigating the role of space in driving cancer evolutionary dynamics.
Typically cancer evolutionary dynamics are thought to proceed along the clonal expansion model shown below. The big bang model (also below, to the right) is one where the dominant clones in the later stages of tumor progression where present at the start. This model encapsulates the idea that it is better to be early than to be good.
The proponents of big bang, Andrea Sottoriva, Christina Curtis and others, have found plenty of evidence of this process going on in many types of cancer including on colorectal ones. Jack has taken a more theoretical approach here and used an agent-based model to study how space can influence whether a tumor can be better characterized as big bang, clonal sweep or something in between. Here is an example of a simulation. The interesting bit is not shown here though: the space expands to accomodate an expanding tumor. But the rate and facility by which it expands can change from simulation to simulation.
The goal is to see how the ease of expanding the available space increases the chances of a tumor being either big bang or clonal sweep. The results? they are preliminary so I won’t spend much time discussing them here but so far it looks like the harder it becomes to find and create space the more likely than the tumor follows a clonal sweep paradigm. Jack and I are working on the manuscript so expect something on the bioRxiv soon.