title: Potential role of gastrointestinal microbiota composition in prostate cancer risk.
abstract: BACKGROUND
  Among men in the U.S., prostate cancer is the most common cancer and the second leading cause of cancer death. Despite its prevalence, there are few established risk factors for prostate cancer. Some studies have found that intake of certain foods/nutrients may be associated with prostate cancer risk, but few have accounted for how intake and metabolic factors may interact to influence bioavailable nutrient levels and subsequent disease risk.
  
  
  OBJECTIVE
  The composition of the gastrointestinal (GI) microbiome may influence metabolism of dietary compounds and nutrients (e.g., plant phenols, calcium, choline) that may be relevant to prostate cancer risk. We, therefore, propose the hypothesis that GI microbiota may have a markedly different composition among individuals with higher prostate cancer risk. These individuals could have microbial profiles that are conducive to intestinal inflammation and/or are less favorable for the metabolism and uptake of chemopreventive agents.
  
  
  METHODS
  Because very little preliminary data exist on this potential association, a case-control study may provide valuable information on this topic. Such a study could evaluate whether the GI microbial profile is markedly different between three groups of individuals: healthy men, those with latent prostate cancer, and those with invasive prostate cancer. Any findings could then be validated in a larger study, designed to collect a series of specimens over time.
  
  
  CONCLUSIONS
  Given the plethora of information emerging from the Human Microbiome Project, this is an opportune time to explore associations between the microbiome and complex human diseases. Identification of profiles that alter the host's risk for disease may clarify inconsistencies in the literature on dietary factors and cancer risk, and could provide valuable targets for novel cancer prevention strategies.
authors.forename: E Susan
authors.initials: ES
authors.lastname: Amirian
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Petrosino
authors.forename: Nadim J
authors.initials: NJ
authors.lastname: Ajami
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Liu
authors.forename: Martha P
authors.initials: MP
authors.lastname: Mims
authors.affiliation: Dan L Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza MS:BCM305, 77030 Houston, TX, USA. scheurer@bcm.edu.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Scheurer