Microbiomic differences in tumor and paired-normal tissue in head and neck squamous cell carcinomasOriginal 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?
Researchers compared the tissue microbiome of tumor versus adjacent normal tissue in head and neck squamous cell carcinoma (HNSCC). The cohort included 121 patients with paired samples from the oral cavity, oropharynx, hypopharynx, and larynx, making it the largest tissue-based HNSCC microbiome study to date.
How was it studied?
DNA was extracted from 242 surgically excised, histologically verified tumor and paired normal tissue samples from 169 enrolled patients. Bacterial content was profiled by 16S rDNA amplicon sequencing (V1 to V4 regions) and analyzed with QIIME, comparing relative abundances using Wilcoxon signed-rank and rank-sum tests.
What did they find?
Overall alpha diversity did not differ between tumor and normal tissue, and tumor/normal grouping explained only a small fraction of total community variation. However, matched-pairs analysis showed Actinomyces, and its parent taxa up to the phylum Actinobacteria, were significantly depleted in tumor tissue (q < 0.01), while Parvimonas was significantly increased in tumor tissue (q = 0.01). Both shifts were more pronounced in patients with higher T-stage disease.
Why it matters
The findings suggest Actinomyces depletion may precede tumor invasion rather than result from it, since the T-stage effect was stronger in adjacent normal tissue than in tumor itself. The authors note node positivity was not linked to Actinomyces abundance, suggesting no role in metastatic potential, and call for validation with next-generation sequencing.