© 2004 AACR

Bacterially induced gut cancers may solidify the role of oxidative stress in tumorigenesis. Medical oncologist Fong-Fong Chu and colleagues at City of Hope's Beckman Research Institute, Duarte, Calif., found that mice missing the glutathione peroxi-dase genes Gpx1 and Gpx2 are more likely to get intestinal cancer if exposed to bacteria, including Helicobacter hepaticus.¹

Both genes protect organisms from oxidative stress, strengthening the belief, says Chu, that such stress can lead to cancer by hastening tumorigenesis. Cancer did not develop in double-knockout mice kept in a sterile environment or in mice with at least one wild-type allele. Chu likens this to inflammatory bowel disease (IBD) models, in which mice, if kept germ-free, do not exhibit disease symptoms.

H. hepaticus is known to cause ileocolitis and colon cancer in mice with severe immune deficiencies. Chu's mice were not immunocompromised. However, the absence of GPXs to counter bacteria-induced...