The immune system works remarkably well for most threats, but not against cancer. Many types of tumors can evade detection, and other fighting. Now Swiss researchers may have discovered a particularly insidious against attack used by some tumor cells: They can force immune cells to commit suicide. The discovery may explain why one of the most common forms of brain cancer is also the most deadly.
aggressive tumors occur in 40% of cases of brain cancer. The new findings, published in the current issue of Journal of Clinical Investigation , suggest that the main attackers, called cell astrocytoma, thrive by exploiting own maintenance process of the immune system. During an infection, immune cells called T cells proliferate to fight against a specific invader, but once the battle is won, excess T cells must be removed to avoid damage to other cells. When a T cell encounters a protein called Fas ligand (FasL) - worn by other T cells -. He destroys
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 it would produce the same signal self- destruction. To test this idea, the team used a genetically engineered cell line that expresses the FasL receptor found on T cells and mixed in with FasL astrocytoma cells bearing mice, rats and humans. The cell astrocytoma kill target cells. And tumor cells taken from patients were found to be just as fatal.
To answer the conclusion, the team must now show that tumor FasL kills T cells in humans. "The real importance in the more complex situation of the growth of human cancer should be studied intensively," says Walker.
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