Yang Y, et al. - In this nested case–control study within the Southern Community Cohort Study, researchers investigated the role of oral microbiome in subsequent development of colorectal cancer (CRC). Study participants included 231 patients with incident CRC and 462 control participants who were individually matched to patients based on age, ethnic group, smoking, season-of-study enrollment, and recruitment method (75% of the study population were African Americans). An increased CRC risk was observed in relation to the presence of oral pathogens Treponema denticola and Prevotella intermedia. Patients with CRC had more Bifidobacteriaceae in the phylum Actinobacteria vs control participants. In the phylum Bacteroidetes, an increased CRC risk was observed in relation to Prevotella denticola and Prevotella sp. oral taxon 300, while a decreased risk was noted in relation to Prevotella melaninogenica. Both African Americans and European Americans exhibited most of these associations, which were not found to be significant after Bonferroni correction for multiple testing. Overall, the researchers showed that there may be a possible significant role of the oral microbiome in CRC etiology.