The baseline oral microbiota predicts the response of locally advanced oral squamous cell carcinoma patients to induction chemotherapy: A prospective longitudinal study

Salivary microbiome changes distinguish response to chemoradiotherapy in patients with oral cancer

BACKGROUND

Oral squamous cell carcinoma (SCC) is associated with oral microbial dysbiosis. In this unique study, we compared pre- to post-treatment salivary microbiome in patients with SCC by 16S rRNA gene sequencing and examined how microbiome changes correlated with the expression of an anti-microbial protein.

RESULTS

Treatment of SCC was associated with a reduction in overall bacterial richness and diversity. There were significant changes in the microbial community structure, including a decrease in the abundance of Porphyromonaceae and Prevotellaceae and an increase in Lactobacillaceae. There were also significant changes in the microbial community structure before and after treatment with chemoradiotherapy, but not with surgery alone. In patients treated with chemoradiotherapy alone, several bacterial populations were differentially abundant between responders and non-responders before and after therapy. Microbiome changes were associated with a change in the expression of DMBT1, an anti-microbial protein in human saliva. Additionally, we found that salivary DMBT1, which increases after treatment, could serve as a post-treatment salivary biomarker that links to microbial changes. Specifically, post-treatment increases in human salivary DMBT1 correlated with increased abundance of Gemella spp., Pasteurellaceae spp., Lactobacillus spp., and Oribacterium spp. This is the first longitudinal study to investigate treatment-associated changes (chemoradiotherapy and surgery) in the oral microbiome in patients with SCC along with changes in expression of an anti-microbial protein in saliva.

CONCLUSIONS

The composition of the oral microbiota may predict treatment responses; salivary DMBT1 may have a role in modulating the oral microbiome in patients with SCC. After completion of treatment, 6 months after diagnosis, patients had a less diverse and less rich oral microbiome. Leptotrichia was a highly prevalent bacteria genus associated with disease. Expression of DMBT1 was higher after treatment and associated with microbiome changes, the most prominent genus being Gemella Video Abstract.

Influence of pathogens on host genome and epigenome in development of head and neck cancer

BACKGROUND

Head and neck cancer (HNSCC) is a heterogeneous group of cancers, affecting multiple regions such as oral cavity, pharynx, larynx, and nasal region, each showing a distinct molecular profile. HNSCC accounts for more than 6 million cases worldwide, soaring mainly in the developing countries.

RECENT FINDINGS

The aetiology of HNSCC is complex and multifactorial, involving both genetic and environmental factors. The critical role of microbiome, which includes bacteria, viruses, and fungi, is under spotlight due to the recent reports on their contribution in the development and progression of HNSCC. This review focuses on the effect of opportunistic pathogens on the host genome and epigenome, which contributes to the disease progression. Drawing parallels from the host-pathogen interactions observed in other tumour types arising from the epithelial tissue such as colorectal cancer, the review also calls attention to the potential explorations of the role of pathogens in HNSCC biology and discusses the clinical implications of microbiome research in detection and treatment of HNSCC.

CONCLUSION

Our understanding of the genomic effects of the microbes on the disease progression and the mechanistic insights of the host-pathogen interaction will pave way to novel treatment and preventive approaches in HNSCC.

Oral microbiome as a new research-target for supportive care and precision oncology

PURPOSE OF REVIEW

A growing number of studies demonstrate the oral bacterial shift in cancer patients and the enrichment of oral bacteria in distant tumours. During the oncological treatment, opportunistic oral bacteria correlate with oral toxicities. This review focused on the most recent studies to identify which genera are the most mentioned and deserved further investigation.

RECENT FINDINGS

This review evaluated bacterial changes in patients with head and neck, colorectal, lung and breast cancer. Greater composition of disease-related genera (e.g., Fusobacterium , Porphyromonas , Lactobacillus , Streptococcus , and Parvimonas ) are present in the oral cavity of these groups of patients. The tumour specimen characterisation of head and neck, pancreatic and colorectal cancer also describes the presence of oral taxa. No evidence indicates that commensal oral bacteria have protective roles in distant tumours. Regardless, oral care is critical to prevent the growth of oral pathogens and reduce infection foci.

SUMMARY

Recent evidence suggests that oral microbiota is a potential biomarker for oncological clinical outcomes and oral toxicities. Currently, the literature presents a remarkable methodological variety - from the sample collection site to the preference of the data analysis tools. For the oral microbiome to achieve the stage of being used as a clinical tool in the oncological context, more studies are necessary.

Fusobacterium nucleatum: a novel immune modulator in breast cancer?

Breast cancer was the most commonly diagnosed cancer worldwide in 2020. Greater understanding of the factors which promote tumour progression, metastatic development and therapeutic resistance is needed. In recent years, a distinct microbiome has been detected in the breast, a site previously thought to be sterile. Here, we review the clinical and molecular relevance of the oral anaerobic bacterium Fusobacterium nucleatum in breast cancer. F. nucleatum is enriched in breast tumour tissue compared with matched healthy tissue and has been shown to promote mammary tumour growth and metastatic progression in mouse models. Current literature suggests that F. nucleatum modulates immune escape and inflammation within the tissue microenvironment, two well-defined hallmarks of cancer. Furthermore, the microbiome, and F. nucleatum specifically, has been shown to affect patient response to therapy including immune checkpoint inhibitors. These findings highlight areas of future research needed to better understand the influence of F. nucleatum in the development and treatment of breast cancer.

The microbiota and radiotherapy for head and neck cancer: What should clinical oncologists know?

Radiotherapy is a linchpin in head and neck squamous cell carcinoma (HN-SCC) treatment. Modulating tumour and/or normal tissue biology offers opportunities to further develop HN-SCC radiotherapy. The microbiota, which can exhibit homeostatic properties and be a modulator of immunity, has recently received considerable interest from the Oncology community. Microbiota research in head and neck oncology has also flourished. However, available data are difficult to interpret for clinical and radiation oncologists. In this review, we focus on how microbiota research can contribute to the improvement of radiotherapy for HN-SCC, focusing on how current and future research can be translated back to the clinic. We include in-depth discussions about the microbiota, its multiple habitats and relevance to human physiology, mechanistic interactions with HN-SCC, available evidence on microbiota and HNC oncogenesis, efficacy and toxicity of treatment. We discuss clinically-relevant areas such as the role of the microbiota as a predictive and prognostic biomarker, as well as the potential of leveraging the microbiota and its interactions with immunity to improve treatment results. Importantly, we draw parallels with other cancers where research is more mature. We map out future directions of research and explain clinical implications in detail.

Cross-comparison of microbiota in the oropharynx, hypopharyngeal squamous cell carcinoma and their adjacent tissues through quantitative microbiome profiling

Aims

To clarify the absolute abundance of microbial communities on hypopharyngeal squamous cell carcinoma and their correlation to those in the oropharynx.

Methods

Clinical data, swabs, and tissue samples from 27 HPSCC patients were collected in this study and divided into three sampling groups: 19 oropharyngeal mucosa (OPM), 27 hypopharyngeal carcinomas tissues (HC), and 26 corresponding adjacent tissues (AT). Relative microbiome profiling (RMP), and quantitative microbiome profiling (QMP) of 16S rRNA amplicon sequencing were used for analysis.

Results

Beta-diversity showed that abundance and phylogenetic tree in OPM group were less when compared to either HC and AT. Although HC and AT were found to have similar microbiota, Bray-Curtis based beta-diversity still highlighted differences. Fusobacterium, Porphyromonas, Haemophilus, and Peptostreptococcus at the genus level in OPM were positively correlated with HC. After categorizing HC through TNM staging, the abundance of genera Fusobacterium, Parvimonas, and Dialister were found to be enhanced in higher T classifications (T3-4) and advanced stages (Ⅳ).

Conclusions

QMP yielded more comprehensive results than RMP. Dysbiosis was found in OPM groups and could be used to narrow down differential microbiome for the HC group. Genera of Parvimonas, Fusobacterium, and Dialister were deemed asrisk factors of advanced HPSCC.

More Than Just a Periodontal Pathogen –the Research Progress on Fusobacterium nucleatum

Fusobacterium nucleatum is a common oral opportunistic bacterium that can cause different infections. In recent years, studies have shown that F. nucleatum is enriched in lesions in periodontal diseases, halitosis, dental pulp infection, oral cancer, and systemic diseases. Hence, it can promote the development and/or progression of these conditions. The current study aimed to assess research progress in the epidemiological evidence, possible pathogenic mechanisms, and treatment methods of F. nucleatum in oral and systemic diseases. Novel viewpoints obtained in recent studies can provide knowledge about the role of F. nucleatum in hosts and a basis for identifying new methods for the diagnosis and treatment of F. nucleatum-related diseases.