Composition of the Gut Microbiome Differentiates Normal Individuals from Those with Precancerous Polyps or Invasive Colorectal Cancer

A recent paper described how analysis of the gut microbiome could be used to differentiate healthy individuals from those with precancerous adenomatous polyps and those with invasive colorectal cancer.

Investigators at the University of Michigan (Ann Arbor, USA) characterized the gut microbiome in 90 patients from three clinical groups representing the stages of colorectal cancer development: healthy, adenoma, and carcinoma (30 patients representing each group). To identify the bacteria present in each individual's gut microbiome, the investigators sequenced the V4 region of the 16S rRNA gene.

They reported that analysis of the gut microbiome from stool samples revealed both an enrichment and depletion of several bacterial populations associated with adenomas and carcinomas. Combined with known clinical risk factors of colorectal cancer such as BMI (body mass index), age, and race; data from the gut microbiome significantly improved the ability to differentiate between healthy, adenoma, and carcinoma clinical groups relative to risk factors alone.

"We found that the composition of the gut microbiome allowed us to identify who in our study had precancerous adenomatous polyps and who had invasive colorectal cancer," said senior author Dr. Patrick D. Schloss, associate professor of microbiology and immunology at the University of Michigan. "If our results are confirmed in larger groups of people, adding gut microbiome analysis to other fecal tests may provide an improved, noninvasive way to screen for colorectal cancer."

"Our data show that gut microbiome analysis has the potential to be a new tool to noninvasively screen for colorectal cancer," said Dr, Schloss. "We do not think that this would ever replace other colorectal cancer screening approaches, rather we see it as complementary."

The gut microbiome study was published in the August 7, 2014, online edition of the journal Cancer Prevention Research.

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