Salivary microbiome profiles of oral cancer patients analyzed before and after treatmentOriginal 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 investigated whether the salivary microbiome of oral squamous cell carcinoma (OSCC) patients differs from healthy controls, and how cancer treatment changes it over time. Paraffin-stimulated whole saliva was sequenced using the V4 region of the 16S rRNA gene on Illumina MiSeq. Reads were denoised with UNOISE3, mapped to zero-radius OTUs, and classified with HOMD. LEfSe, PERMANOVA, and Global Test analyses compared groups and timepoints.
Who was studied?
The study included 99 pre-treatment OSCC patients and 101 age- and sex-matched healthy controls in Finland, all largely of Caucasian ethnicity. After a mean follow-up of about 48 months, 28 patients provided post-treatment saliva samples. Saliva was collected before surgical tumor resection and after adjuvant therapy. The cancer group contained more smokers than controls (p less than 0.001), which was adjusted for.
What were the most important findings?
OSCC patients' salivary profiles differed significantly from controls (PERMANOVA F = 5.9, p less than 0.001), with no difference in Shannon diversity. The difference persisted after excluding smokers, drinkers, and edentate subjects (F = 2.4, p less than 0.001). OSCC saliva was enriched in Streptococcus anginosus, Abiotrophia defectiva, and Fusobacterium nucleatum, bacteria linked to systemic infection. After treatment, profiles differed significantly from baseline (F = 2.3, p less than 0.001) with significantly lower alpha diversity (p = 0.008) and a shift toward aciduric taxa, still evident years later.
What are the greatest implications of this study?
The findings show OSCC is associated with a distinct, pathogen-enriched salivary microbiome, and that treatment drives an ecologically unfavorable shift with reduced diversity that endures for years. The authors suggest OSCC patients may benefit from prevention such as probiotics, saliva substitutes, or dietary counseling, and long-term dental follow-up. Limits include few post-treatment samples, missing periodontal records, and smoking that could not be fully corrected. Intervention studies are needed.