Since Sidney Farber's landmark research in 1948 demonstrated that folic acid antagonists could temporarily suppress acute undifferentiated leukemia in children, chemotherapy has developed into an effective treatment method to stop uncontrollable cancer cell growth.

A new study revealed another milestone: we now know exactly how chemotherapy works. And, as a result, researchers may have a whole new path to developing innovative tactics to treat cancer.

Previously, the anticancer drugs used in chemotherapy were thought to function like antibiotics and directly kill off cancer cells. But now it seems as though they work by communicating with and activating the body's immune cells.

"Successful chemotherapeutics convert the tumor into a therapeutic vaccine, hence mobilizing the host's immune system against the cancer," said Guido Kroemer, lead author and senior scientist at the Institut Gustave Roussy in France.

The French study described chemotherapy step by step. The chemicals used in chemo first burst open cancer cells, destroying them and releasing an enzyme called ATP, or adenosine triphosphate. ATP, in healthy cells, transports chemical energy within the cells during metabolism. In chemotherapy, ATP travels the body region, gathering immune cells, and then drives them toward tumor infested regions and trains them to ingest and acquire the ability to recognize future cancer cells.

According to Kroemer, this could lead to future chemotherapies that could increase the presence of immune cells in regions where there's an overwhelming amount of cell growth.

"Anticancer therapies and immunotherapies might be combined in a way to optimize the local recruitment and function of immune cells-for instance, by increasing extracellular ATP levels-with the goal of boosting the chemotherapy-induced anticancer immune response," Kroemer said.

Overall, chemotherapy increases the survival rate of cancer patients, although it also attacks healthy cells and has side effects such as loss of hair, diarrhea, fatigue, changes in mouth and throat, pain, and fertility changes, among others.

The good often outweighs the bad; in breast cancer patients for example, chemotherapy increases the survival rate by 88 percent, compared with 76 percent for those not on chemotherapy.

The findings of this new study was published online on April 4 in the journal Immunity.