Immunotherapy is the new revolution in cancer treatment. As scientists discover new ways to adapt, or amplify, the body's natural defenses it opens the door to the development of better weapons to destroy tumors and kill cancers. With the potential to improve the effectiveness of such treatments, a new study has revealed insights into a possible "master switch" protein that directs immune cells to germs or cancers.

T-cells are white blood cells produced by the body that are fundamental to our immune system. Cancer immunotherapy concentrates on a specific form of these cells called CD8+ T-cells, which are the T-cells that specifically destroy tumors or other virus-infected cells.

One way scientists are manipulating the body's natural defenses is called adoptive cell transfer, which involves extracting a patient's own T-cells, genetically modifying them to target the specific proteins that mark cancer cells, and then injecting them back into the patient.

This kind of therapy is proving promising against some specific cancers, such as blood and bone marrow, but not as effective in targeting cancers with solid tumors. One of the key mysteries in this regard that scientists haven't been able to uncover is exactly what mechanism directs the T-cells from home base to specific compromised tissues.

A new study from The Scripps Research Institute and the University of California, San Diego, has found a possible protein target that could be a T-cell's head programmer, directing these immune weapons to their desired locations.

The research ended up homing in on a protein called Runx3. After animal model testing it was discovered that Runx3 seems to direct the T-cells to attack solid tumors, and when Runx3 was overexpressed the animals experienced delayed tumor growth and extended survival.

"Runx3 works on chromosomes inside killer T cells to program genes in way that enables the T cells to accumulate in a solid tumor," explains Matthew Pipkin, from Scripps. "If we enhance Runx3 activity in the cells, the tumors are significantly smaller and there is greater survival compared to the control group."

Pipkin suggests that this discovery could enhance the effectiveness of general adoptive cell transfer treatments, helping direct those engineered T-cells to find and kill the desired cancer cells.

The study was published in the journal Nature.