During the development of many types of cancer, cells divide until they form a large mass, containing billions of cells. Understanding how the cancer grows is obviously an important scientific and medical goal.
One way to examine this question is to run computer simulations of cancer growth and see how changing different parameters affect the outcome. The image represents a 3-dimensional structure of a growing cancer in one such simulation. The colors correspond to different genetic mutations within cells.
Such a large mass of cells would normally contain many mutations that accumulate as cells divide. But here the results show that cells in the cancer contain just a core set of key mutations that allow the cells to divide faster. Any mutation that gives a cell even a small growth advantage will be inherited by all the descendant cells, resulting in clumps of cells that are genetically similar.
The image has been generated by a computer program which first simulated the tumor, then colored cells within the tumor using their genetic relatedness (similar colors corresponding to genetically similar cells), and rendered a 3D image using a simple ray-tracing algorithm.
Bartek Waclaw, PhD, School of Physics and Astronomy, University of Edinburgh, Scotland and Martin Nowak, PhD, Program for Evolutionary Dynamics, Harvard University, Cambridge, MA