Cited research: Cell 141, 583–594 (2010)

In many cancers, tumour growth has been attributed to a small, fixed subset of cells known as cancer stem cells. But melanomas are thought to follow a different path. Researchers now report that a dynamic group of melanoma cells is responsible for continuous tumour growth, with individual cells in this group transiently acquiring and losing this ability to drive tumour growth.

Meenhard Herlyn at the Wistar Institute in Philadelphia, Pennsylvania, and his colleagues found that the enzyme JARID1B, which is involved in cancer and in normal stem-cell biology, is a marker for this subpopulation of melanoma cells. Silencing the JARID1B gene in human melanoma cells in vitro resulted in an initial increase in cell proliferation, which then levelled off. When transplanted into mice, the JARID1B-knockdown cancer cells eventually stopped dividing. They also resulted in the formation of fewer secondary lung tumours.

Cells positive or negative for the enzyme each gave rise to a mixed population of these two cell types. C.L.