Boosting Killer Cells Might Improve Breast Cancer Drug

Preliminary research suggests that the substance interleukin (IL)-21 might improve the effectiveness of the drug trastuzumab (Herceptin) in treating HER2-positive breast cancer. Laboratory and animal study findings suggest that this happens because the IL-21 boosts the cancer-killing activity of immune cells called natural killer (NK) cells, which attack the tumor.

The findings by researchers at the Ohio State University Comprehensive Cancer Center—Arthur G. James Cancer Hospital and Richard J. Solove Research Institute were published in the July 1 issue of

The Journal of Immunology

. The researchers hope to begin a clinical trial to test the strategy in humans soon.

Increased Immune Response

"Only 25% to 35% of patients with this form of breast cancer respond to Herceptin," said principal investigator Dr. William E. Carson III, associate professor of surgery and associate director for clinical research at the OSU Comprehensive Cancer Center. "Our results suggest that giving IL-21 along with the Herceptin might increase the patient's immune response to the tumor and perhaps boost the drug's effectiveness."

Many researchers believe that trastuzumab works because it stops tumor cells from growing and causes them to self-destruct through the natural process of programmed cell death, explained first author Julie M. Roda, a graduate research associate in Carson's laboratory. But, she adds, "our findings provide new evidence that Herceptin works at least in part by stimulating NK cells activity, and that IL-21 enhances that action."