New Mesothelioma Treatment? Stanford Scientists Hopeful about Many Cancers
March 29, 2012
If mice in the laboratory are any indication — and that’s always a really big if — immunologists at Stanford University School of Medicine may be getting close to a treatment that will allow a body’s own immune system to fight off most cancers.
Scientists at Stanford tested an antibody treatment that was successful in shrinking human liver, prostate, colon, bladder and breast cancer tumors that were transplanted into mice.
The treatment was not tested against mesothelioma tumors, but early indications are that it could work against virtually all cancers.
Cancerous tumors in humans often behave differently than in mice, but the results have been so promising that the Stanford group has been awarded a $20 million grant from the California Institute for Regenerative Medicine to begin launching human safety tests.
“We have enough data already that I can say I’m confident that this will move to phase I human trials,” Irving Weissman, M.D., told Science Now.
The treatment involves blocking a protein called CD47, which normally stops a body’s immune system from attacking the cancerous tumor. By negating the effectiveness of CD47, which is on the surface of the cells, the body’s own immune system will seek out and destroy the cancerous cells.
Weissman has worked with CD47 for a decade, discovering that an antibody was effective against leukemia and other blood cancers. For the first time, though, scientists are discovering its effectiveness against other cancers.
Human bladder cancer tumors, transplanted into mice, were stopped from spreading 90 percent of the time after an anti-CD47 treatment. Colon cancer tumors transplanted into mice shrank to less than one-third their size, on average. Breast cancer tumors in five mice disappeared after the treatment, and the mice remained cancer free four months later.
“If the tumor was highly aggressive, the antibody also blocked metastasis. It’s becoming very clear that, in order for a cancer to survive in the body, it has to find a way to evade the cells of the human immune system,” Weissman said in a statement.
To first determine whether blocking CD47 would work, scientists at Stanford exposed tumor cells to a type of immune cell, in petri dishes. Without the antibody, the immune cells ignored the cancer cells. Once the antibody was used, the immune cells destroyed the cancer cells.
Mesothelioma is a rare cancer that is caused by the inhalation of microscopic asbestos fibers , which often lodge in the thin lining surrounding the lungs and other organs. There is no known cure and prognosis is typically poor because the diagnosis normally comes after the disease has spread.
Advances in any cancer treatment often are watched closely by those studying mesothelioma.