Scientists have found the Achilles’ heel of cells that jump start tumor growth. According to a new study, these “cancer stem cells” reside in blood vessels. Cancer biologists once believed that all cells in a tumor were pretty much the same. But in the early 1990s, a team found some interesting characters hanging out with leukemia cells: Instead of rapidly dividing like their million-fold-more-plentiful companions, these outliers grew slowly. And when transplanted to a petri dish, they gave rise to the more common type of leukemia cell.
So neurobiologist Richard Gilbertson at St. Jude Children’s Research Hospital in Memphis, Tennessee, and colleagues began looking for a weakness. They started by comparing cancer stem cells to noncancerous neural stem cells. These neural tissue precursors are concentrated in regions rich in blood vessels. The vessels are lined with endothelial cells, which secrete chemical signals that help stem cell survive. Gilbertson’s team wondered whether cancer stem cells might require a similar niche.
Sure enough, after examining over 70 human brain tumors, the researchers found that cancer stem cells were frequently located close to tiny vessels called capillaries.