Longitudinal study links salivary microbiome changes to chemoradiotherapy response in oral cancer patients (microbiomejournal.biomedcentral.com)

• Salivary microbiome richness and diversity decrease after oral cancer treatment, especially with chemoradiotherapy.
• Prevotella abundance pre-treatment is associated with non-response to chemoradiotherapy.
• DMBT1, an anti-microbial protein, is suppressed by SCC and increases post-treatment, correlating with specific bacterial changes.

"This longitudinal study analyzed the salivary microbiome of oral squamous cell carcinoma (SCC) patients before and after treatment using 16S rRNA gene sequencing. Treatment, particularly chemoradiotherapy, reduced bacterial richness and diversity. Specific bacterial families decreased (Porphyromonaceae, Prevotellaceae) while Lactobacillaceae increased. Pre-treatment, Prevotella was associated with non-responders, while post-treatment, Veillonella, Streptococcus, Rothia, Gemella, and others correlated with response. The anti-microbial protein DMBT1 was suppressed in SCC saliva but increased after treatment, and its expression correlated with specific bacterial changes, notably Gemella. This is the first study to longitudinally link oral microbiome changes with an anti-microbial protein and treatment outcome."