Antidote: On cancer and CD47
Marc Siegel, MD
Here's one story the news media may have gotten right. Stanford researchers, led by pathologist Dr. Irving Weissman, have been conducting studies in mice—introducing antibodies to a protein known as CD47. CD47 is produced by normal cells to alert passing white blood cells not to attack them. The purpose of our immune system is protect us against foreign invading organisms, and CD47 alerts our immune system not to attack normal cells.
The problem is that cancer cells produce this protective protein in large amounts. It helps cancer to avoid being destroyed by our immune system. But now Weissman and his group have created a treatment which blocks CD 47 in cancer cells, thereby allowing our white blood cells to attack. This drug has had amazing affects against cancers of many kinds including breast, ovary, colon, liver, brain, prostate and bladder.
Next stop, humans. After a convincing study just published in the Proceedings of the National Academy of Science, Weissman's group has received FDA approval to proceed with human trials. The media covered this news, and emphasized the potential of the drug, which could be enormous.
It may be too soon to call it a cure, but nevertheless, the anti-CD47 drug leads the way in the new targeted treatments against cancer. By convincing the body that cancer is abnormal, either by protein, hormone, or genetic analysis and manipulation, scientists are creating treatments and vaccines (using the body's own immune cells) to directly target the tumor.
If the human studies deliver on this promise, new drugs will be in the pipeline for human use, and we can likely look forward to powerful new treatments within five years.Scientists have been working on the characteristics of the CD47 membrane protein and the gene that produces it for two decades. They are now finally getting traction on treatments to block it, thereby thwarting cancer. Without CD47 to protect it, cancer can be targeted for destruction by our immune cells at an early stage. Now that's a story worth reporting.