Strep bacteria may treat pancreatic cancer

By David Douglas

NEW YORK (Reuters Health) - In mice implanted with human pancreatic cancer tumors, injecting live Streptococcus bacteria, similar to those that cause strep throat, directly into the tumors caused the tumors to shrink and die, German scientists report.

"The utilization of live bacteria," as a danger signal, Dr. Claudia Maletzki told Reuters Health, "obviously has great potential for activating the immune system."

Given the poor prognosis of patients with advanced pancreatic cancer, "novel" interventions are "imperative," Maletzki and colleagues at the University of Rostock note.

In culture experiments, the researchers established that streptococcal bacterium known as S. pyogenes could mediate severe injury to pancreatic cancer cells.

The team went on to examine the efficacy of S. pyogenes in a mouse model of aggressive pancreatic cancer known to have an intrinsic insensitivity to existing anti-cancer agents.

They found that a single application of the live bacteria resulted in complete regression or death of the pancreatic tumors.

In addition to direct destructive activity, they observed a helpful tumor-specific immune response, with generation of tumor-specific cells.

"We think that patients suffering from tumors with very bad prognosis could substantially benefit from such alternative treatments stimulating the immune system," Maletzki said.

SOURCE: Gut, April 2008.