A biomedical research team at Stanford University School of Medicine reported yesterday the results of mouse experiments using an antibody molecule to treat various types of tumorous cancer cells — with results showing significant tumor shrinkage and slowed tumor growth in all cancer cell types tested. In some cases, the tumorous cells were completely destroyed by host immune cells with no recurrences four months after the treatment was stopped.
This breakthrough results from the application of an earlier discovery by Irving Weissman some ten years ago showing that a certain cell marker protein — known as CD47 — normally found on the surfaces of blood cells, serves as a biological “flag” to immune cells, telling them “don’t eat me”. As it turns out, cancer cells have found away to exploit this innate host protection by secreting the same molecular flag as normal blood cells.
Macrophages — large “killer cells” of the immune system — “see” the correct flag, and generally leave the cancer cells alone to replicate, and even metastasize (i.e., spread throughout the body).
In just the past few years, the research team, led by Dr. Weissman, developed an antibody that blocks production of the CD47 cell marker, and then more recently began trying out the antibody on blood cancers such as leukemia.
“What we’ve shown is that CD47 isn’t just important on leukemias and lymphomas. It’s on every single human primary tumor that we tested.”, said Weissman [source: Science Now].