Colorectal Cancer Patients Have Four Specific Bacterial Species in Oral and Gut Microbiota in Common-A Metagenomic Comparison with Healthy SubjectsOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study evaluated the role of oral microbiota in colorectal cancer (CRC) progression by comparing bacterial communities in saliva and stool. Researchers used 16S rRNA analysis and next-generation sequencing to characterize both sample types. Linear discriminant analysis effect size (LEfSe) was applied to identify bacterial species that differed significantly between groups and across CRC stages.
Who was studied?
The study included 52 patients with colorectal cancer and 51 healthy controls, with saliva and stool samples collected from each participant. CRC patients were further divided into an early-stage group (Stage I or II, n = 26) and an advanced-stage group (Stage III or IV, n = 26). This design allowed comparison not only between CRC patients and healthy subjects but also between disease stages.
What were the most important findings?
Indigenous oral bacteria, including Peptostreptococcus, Streptococcus, and Solobacterium species, were present at significantly higher relative abundance in both saliva and stool of CRC patients compared with healthy controls. Among these, Peptostreptococcus stomatis, Streptococcus anginosus, Streptococcus koreensis, and Streptococcus moorei were identified as oral-cavity-derived species shared between the two body sites in CRC patients. Streptococcus moorei was further found at significantly higher relative abundance in advanced-stage (Stage III, IV) patients compared with early-stage (Stage I, II) patients, and this pattern held consistently in both saliva and stool samples.
What are the greatest implications of this study?
The consistent presence of the same four oral-derived bacterial species in both saliva and stool of CRC patients supports a link between oral microbiota and gut microbiota in CRC. The stage-dependent enrichment of Streptococcus moorei suggests these oral bacteria may track with, or contribute to, CRC progression rather than merely being present. These findings raise the possibility that saliva-based microbial signatures could serve as accessible, non-invasive markers related to CRC status or stage.