It sounds too good to be true, but Standford University scientists have discovered a single drug that can shrink, or even completely cure human cancer tumors. The question is how a drug like that works, and when will it be available.
The drug blocks a protein called CD47, which is produced in large amounts by cancer cells. The protein keeps the body’s immune system from fighting tumors, and so by shutting down CD47 production the new drug effectively leaves cancer cells susceptible to the body’s own natural defenses.
In the lab, cancer cells were transplanted into mice, and the drug was found to successfully prompt the rodent’s immune systems to kill cancer cells of the bladder, liver, prostate, ovary, colon and breast.
“We showed that even after the tumor had taken hold, the antibody can either cure the tumor or slow its growth and prevent metastasis,” said researcher Irving Weissman of the Stanford University School of Medicine, in an interview with Science Magazine.
Over the past few years, this particular technique has been applied to treating lymphomas and leukemias, but this latest research suggests it could be used on all types of cancers. As Weissman recently explained to Science Magazine:
“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… We showed that even after the tumor has taken hold, the antibody can either cure the tumor or slow its growth and prevent metastasis.”
However, as cancer researcher Tyler Jacks of the Massachusetts Institute of Technology in Cambridge is quoted as saying in an editorial in Science Magazine, “the microenvironment of a real tumor is quite a bit more complicated than the microenvironment of a transplanted tumor, and it’s possible that a real tumor has additional immune suppressing effects”.
Another factor needing examination relates to the fact that healthy cells produce the CD47 protein. It is not known as yet what effect the antibody would have on healthy human tissues. As this animal research demonstrated, the antibody did seem to cause depletion in blood count in mice. This would be a significant adverse effect in humans with cancer, and the implications of such safety effects would have to be considered before this treatment could proceed to human testing.
Overall, much more research is needed before it will be known whether this treatment could truly offer the potential to shrink or halt the progression of human cancers. Still, results remain promising as researchers have just received a $20 million grant to move the findings from mouse studies to human safety tests.