Page 3
``Every day we find different ways that cancer cells evade the immune system and here is another,'' said Sznol. Lee and his colleagues speculate that the T cells may recognize the cancer cells, but that some compound secreted by invaders shuts down the attack response of the immune system. In theory, the tumors may kill or damage the so-called antigen-presenting cells, middleman cells that alert T-cells to the presence of unwanted peptides, suggested Sznol.
Current therapies that seek to activate the immune system against cancer, such as the drug interleuken, only help about eight percent of patients who take them, said Sznol. Further tetramer analysis of the changes in the immune system caused by tumor cells may allow a fine-tuning of such drugs for better performance. Cancer kills more than 500,000 people nationwide annually, according to the American Cancer Society in Atlanta, and Sznol said tumors may stop the immune system in subtly different ways in each patient. ``Ultimately, we want to activate the immune system to wipe out each cancer,'' he said.
A paradox exists in cancer immunology, noted Dr. Francesco Marincola, also a researcher at the National Cancer Institute. When scientists vaccinate cancer patients with large numbers of peptides to stimulate their immune system to attack cancer, T cell counts go way up, but no decrease in tumor cells results.
``Studies like this one provide insight into how the immune system breaks down, something that may lead to cancer vaccines,'' said Marincola.
Researchers from the University of California at San Francisco, University of Southern California in Los Angeles, and University of Washington in Seattle participated in the study.
----
Nature Medicine (1999;5: 676-685) The Medical Tribune Web site is at http://www.medtrib.com
| Here's the follow-up discussion on this article: | View all related messages |
For a complete listing of article comments, questions, and other discussions related to Bobbi Jones's Breast Cancer topic, please visit the Discussions page.