Previous research has shown that a common theory is that tumours are a hierarchical society, in which all cancer cells descend from special self-renewing cancer stem cells. This view predicts that killing the cancer stem cells might suffice to wipe out a cancer.
But new findings by scientists at the Broad Institute of MIT and Harvard and Whitehead Institute, point to a much more decentralized society, with cancer cells able to interconvert between different types.
These results have potential implications for the treatment of tumours, in particular, that attacking cancer stem cells alone may not be enough to fight cancer.
The common view is that tumours have cancer stem cells that behave like stem cells in normal development - at the top of a hierarchy of cell types, giving rise to both more cancer stem cells and daughter cells of other types.
"The notion is that the only way stem cells occur is by self-renewal. Our work says that analogy may be wrong," said Broad director and senior author Eric Lander.
The new work suggests an alternative possibility: that cancer cells are not fixed at all, but that, at any given point in time, they exist in one of several phenotypic "states" and those states can interconvert.
In comparison to the traditional one-way hierarchy of cancer stem cells, in this new alternate model, more differentiated non-stem cells can revert to being stem-like cells.
"That's not a hierarchical society at all. Cells aren't born into a medieval guild; they can change jobs," added Lander who led the study with author Piyush Gupta, a Whitehead Institute member and assistant professor of biology at MIT.
The findings appeared in the August 19 issue of Cell.