An article in the Proceedings of the National Academy of Science explains that a new treatment — based on an antibody that blocks a “do not eat” signal normally displayed on tumour cells — helps persuade the immune system to destroy the cancer cells. To date, it’s been shown to shrink or cure human breast, ovary, colon, bladder, brain, liver and prostate tumours that have been transplanted into mice.
The treatment targets and blocks a protein called CD47, a marker that tells the immune system to not kill healthy blood cells. But cancers use the same protein to avoid being destroyed by the body, too — so by strategically blocking the protein, it’s possible to use one antibody to kill all types of cancer tumours.
Over the past few years the technique has been applied to treating lymphomas and leukaemia, but this latest research suggests it could be used on all types of cancers. Irving Weissman, one of the researchers, explains to Science:
“What we’ve shown is that CD47 isn’t just important on leukemias and lymphomas. It’s on every single human primary tumour that we tested… We showed that even after the tumour has taken hold, the antibody can either cure the tumour or slow its growth and prevent metastasis.”
Even though some normal, healthy cells are attacked as a result of blocking CD47, the researchers found this was short-lived and negligible compared to the effects on the tumour.
Sadly, it will be some time before such a drug makes it to clinical practice. But with the researchers having just received a $US20 million grant to move the findings from mouse studies to human safety tests, you can expect progress to be as quick as possible. [PNAS via Science]