Bug behind the stomach cancer also linked to colon cancer

FRIDAY, Oct. 12, 2018 (HealthDay News) – New study finds same type of bacteria that causes stomach cancer may increase risk of colon cancer, especially among black Americans

The researchers analyzed data from more than 4,000 cases of colon or rectal cancer in the United States. They found a significant association between the rates of these cancers and infection with a virulent strain of H. pylori bacterium that is particularly common among black Americans.

The results do not prove that H. pylori causes cancer of the colon or rectum, however. Further investigation is needed, noted the authors of the study.

"The link between infection and cancer is intriguing, especially if we can eradicate it with a simple series of antibiotics," said the study's author, Meira Epplein, cancer epidemiologist at the Duke Cancer Institute.

"Our study clearly demonstrates that we need to continue this research to establish a definitive cause-and-effect relationship," Epplein added in a press release published by Duke University.

The researchers found that antibodies indicating H. pylori infections were also common in patients with colorectal cancer and those without cancer – four out of 10 patients were positive.

However, there were important racial differences.

White patients were below average H pylori infection rates, Americans of Asian origin had average rates, while blacks and Hispanics had high rates. Among Blacks, the rates were 71% for patients with colorectal cancer and 65% for non-cancer patients. Among Hispanics, the rates were 74% in cancer patients and 77% in those without cancer.

Watch antibodies against four H. pylori The researchers found that one protein in particular, VacA, was most closely related to an increased risk of colorectal cancer in black Americans. High levels of antibodies against this protein were associated with colorectal cancer rates in blacks and Americans of Asian origin.

"It was surprising that anti-VacA antibodies increased the risk of colorectal cancer in African-Americans and Americans of Asian descent, not in whites and Latinos," Epplein said. "It's a big question: do people harbor different bacteria based on genetic origin or heritage?" That's part of what we need to understand. "

Other studies could reveal whether anti-VacA antibodies could serve as a marker for the risk of colorectal cancer, even if it does not directly cause cancer, Epplein said.

The results were published online on October 5 in the journal Gastroenterology.

More information

The American Cancer Society has more on colorectal cancer.