Salmonella may join fight against cancer

By altering a salmonella bacterium and rigging it to produce a protein found predominantly in cancer cells, scientists have devised an experimental cancer vaccine.

Researchers created the vaccine by making a nonvirulent form of Salmonella typhimurium and adding a gene for the tumor-cell protein NY-ESO-1. When mingled with human white blood cells in a lab dish, the vaccine elicited the formation of an army of immune T cells that recognize and target cells producing NY-ESO-1.

When fed to mice that had cancer, the vaccine caused regression of the cancer, the researchers report in the July Journal of Clinical Investigation.

NY-ESO-1 is present in several malignancies, including cancers of the lung, ovaries, blood, breast, and skin. In contrast, the protein isn’t produced much at all in normal tissues, says study coauthor Sacha Gnjatic, an immunologist at the Ludwig Institute for Cancer Research in New York City.

Cancer vaccines aren’t like traditional vaccines; they’re treatments designed to alert the body to the presence of established cancer and to prompt the immune system to attack malignant cells. Most such vaccines have shown only modest success to date. This new one might be tested in people within a year, Gnjatic says.