Macrophages are the most likely kind of immune cell to detect and destroy a tiny cluster of cancer cells before things get out of hand. T and NK cells tend to circulate in the blood, rather than patrolling the tissues where cancers start. Macrophages are giant cells that travel around the body, engulfing and digesting anything that looks suspicious - bacteria, debris and body cells that don't feel right.
Scientists in the University of Stanford have now discovered one of the ways in which cancer cells protect themselves. They have "don't eat" me flags on them. These flags are messages directed at macrophages. What is more, they have successfully tested an antibody that can block this flag, allowing macrophages to identify and devour cancer cells.The cancer cells in question were not just a single type but a highly diverse selection, originally human in origin, which were implanted in mice. The team must have been delighted to discover that the antibody disabled the flags on a very wide range of cancer cells leaving themselves vulnerable to murder by macrophage.
This opens up the exciting possibility of a new antibody-based treatment that could potentially treat a wide range of cancers. It could be the holy grail of cancer research, as the few existing new-wave treatments like Herceptin, are extremely specific and bring benefit only a small group of patients. Developing drugs like this, one at a time, is very slow and extremely expensive. This translates into a very high price tag for the drug when it is released. If this discovery could be turned into a new broad-spectrum cancer treatment for humans it could provide a much cheaper solution available to both rich and poor.