Scientists hope clinical trials with a new therapeutic anticancer antibody could start within the next couple of years, after studies in mice showed that the treatment dramatically shrinks—and in some cases completely eliminates—a wide range of human solid tumor types. A Stanford University Medical Center-led team has expanded on work suggesting that expression of CD47 on the surface of tumor cells acts as a "don’t eat me" signal protecting them from engulfment by phagocytic cells. Their latest studies showed that using a tumor-targeting monoclonal antibody to block CD47 on the surface of cancer cells effectively removes this immunity to phagocytosis, both in vitro and in mice carrying different types of human tumors.

In vivo studies showed that when antibody therapy was started early after engraftment of tumor cells in mice, the treated animals were protected against tumor development, and remained tumor-free even after antibody therapy was withdrawn. When the antibody was administered to animals with already evident tumors, further growth of the cancer was halted, and metastasis prevented.

Importantly, the investigators also found that human patients whose tumors expressed higher levels of CD47 had poorer survival. Irving L. Weissman, M.D., and colleagues report their findings in PNAS, in a paper titled “The CD47-signal regulatory protein alpha (SIRPα) interaction is a therapeutic target for human solid tumors.”