Medical College of Wisconsin Researchers Study Role of H pylori in Stomach Cancer

Publication
Article
OncologyONCOLOGY Vol 10 No 10
Volume 10
Issue 10

Medical College of Wisconsin researchers recently reported on a study linking Helicobacter pylori to precancerous lesions of the stomach. By infecting specially bred mice with H pylori and showing the resulting precancerous changes in their stomachs, the researchers have uncovered an important clue to the origins of stomach cancer. Their results are the closest evidence to date showing that H pylori causes stomach cancer in any animal model.

Medical College of Wisconsin researchers recently reported ona study linking Helicobacter pylori to precancerous lesionsof the stomach. By infecting specially bred mice with H pyloriand showing the resulting precancerous changes in their stomachs,the researchers have uncovered an important clue to the originsof stomach cancer. Their results are the closest evidence to dateshowing that H pylori causes stomach cancer in any animalmodel.

Until about 10 years ago doctors thought the stomach was a sterileenvironment, explained Bruce Dunn, md, associate professor ofpathology at the Medical College. Gastric juices are so potentthat they assumed no bacteria could live in them. Then came thediscovery that H pylori could, indeed, survive in the stomach;it causes gastritis and peptic ulcers. A percentage of peoplewith gastritis go on to develop stomach cancer.

The natural follow-up question was, does H pylori playa role in stomach cancer? Based on epidemiologic studies, theanswer seemed to be "yes." A correlation has been establishedbetween some strains of H pylori infection and developmentof stomach cancer, but this correlation needs to be demonstratedin a laboratory.

That's what Dr. Dunn and his colleague, Suhas H. Phadnis, phd,assistant professor of pathology, set out to do at the VA MedicalCenter.

Beyond the Tumor-Suppressor Gene

Scientists know that for most cancers to develop, there must bea mutation in the tumor-suppressor gene, p53. They have bred astrain of laboratory mice without this gene, who then go on todevelop lymphatic cancer. But the mice don't develop stomach cancer,which suggests that, in addition to the absence of the tumor-suppressorgene, something else must be present in order for this cancerto develop.

Drs. Dunn and Phadnis infected p53-deficient mice with H pylorito see if they would develop stomach cancer. The answer, so far:"The mice don't develop cancer, but they do develop dysplasiawhich is a significant precancer stage," said Dr. Dunn. Drs.Dunn and Phadnis think the reason the p53-deficient mice don'tget full-blown cancer is because of their short life span. Stomachcancer in humans seems to take years, or even decades, to develop.The researchers are now studying the combined effects of Hpylori and low levels of known carcinogens to see whetherthere is a synergistic effect that can be observed during thelife span of the mice.

A second area of their research is an attempt to discover howthe H pylori bacteria manage to stay alive in the hostilestomach environment. The theory is that they "wrap"themselves in a shield of ammonia made by breaking down urea presentin the gastrointestinal tract. The Wisconsin investigators hopeto prevent the enzyme urease (which breaks down the urea) fromdoing its job. That could lead to a vaccine to prevent the consequencesof infection with H pylori, such as peptic ulcer and gastriccancer.

Dr. Dunn presented the research at the 14th annual Media Seminaron Cancer on April 15, 1996, at the Medical College of Wisconsin.

Recent Videos
“Everyone—patients, doctors—we all want the same thing. We want [patients] to live longer,” said Kiran Turaga, MD, MPH, on patients with peritoneal surface malignancies.
Data from the phase 3 DeLLphi-304 trial at ASCO 2025 revealed a survival advantage with tarlatamab vs chemotherapy in second-line ES-SCLC.
The new peritoneal surface malignancy care guidelines had clinicians gather from every disease state to show increased representation.
The FDA approval of tarlatamab in SCLC has received much press attention, according to Daniel R. Carrizosa, MD, MS.
These new guidelines aim to alleviate some of the problems caused by patients with peritoneal metastases being diagnosed with the disease in late stages.
A combined cohort composed of patients from the TROPION-Lung01 and TROPION-Lung-05 trials showed a survival advantage with dato-DXd vs docetaxel.
The National ICE-T Conference may inspire future collaboration between community and academic oncologists in the management of different cancers.
4 experts in this video
Related Content