November 1, 2005

Researchers at Mount Sinai School of Medicine in New York City are conducting clinical trials on a unique approach to enhance the immune system in patients with breast or colorectal cancer. The study uses a potent immune-enhancing gene delivered directly into the cancer cells to make them look foreign to the body's immune system, which will then attack and destroy the cancer.

In experiments with laboratory animals, Mount Sinai researchers have demonstrated that their approach, known as tumor immunization, extended life in all the animals tested and wiped out cancer entirely in 20 to 30 percent of animals whose breast or colorectal cancer had spread. With currently available treatments, the prognosis for patients with breast or colorectal cancer that has spread to other organs, including the liver, is poor.

The method of tumor immunization that researchers developed involves transferring a gene that codes for Interleukin-12 (IL12) into cancer cells directly in the patient's tumor. IL12 is a potent immune-enhancing protein that is not normally produced by cancer cells. When the cancer cells produce this protein as a result of gene transfer, it acts as a signal to a special class of white blood cells of the immune system, prompting them to attack the cancer cells.