- News Home
17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
- About Us
How Tumors Fight Back
21 March 1997 8:00 pm
The immune system works remarkably well for most threats, but not against cancer. Many kinds of tumors can evade detection, and others fight back. Now Swiss researchers may have uncovered a particularly devious counterattack used by certain tumor cells: They can force cells of the immune system to commit suicide. The finding may explain why one of the most common forms of brain cancer is also the deadliest.
Aggressive tumors occur in 40% of brain cancer cases. The new findings, reported in the current issue of the Journal of Clinical Investigation, suggest that the main attackers, called astrocytoma cells, flourish by exploiting the immune system's own housekeeping process. During an infection, immune cells called T lymphocytes proliferate to fight a specific invader, but once the battle is won, the excess T lymphocytes must be eliminated to prevent damage to other cells. When a T lymphocyte encounters a protein called Fas ligand (FasL)--carried by other T cells--it self-destructs.
Phillipe Saas, Paul Walker, and colleagues at the University Hospital of Geneva found that astrocytoma cells also carry FasL on their cell surfaces, and they reasoned that this would produce the same self-destruct signal. To test that notion, the team used a genetically modified cell line that expressed the receptor for FasL found on T lymphocytes and mixed in FasL-bearing astrocytoma cells from mice, rats, and humans. The astrocytoma cells killed the target cells. And tumor cells taken from patients proved just as deadly.
To clinch the finding, the team must now show that FasL from tumors kills T lymphocytes in humans. "The real importance in the more complex situation of human cancer growth has to be intensively investigated," says Walker.