Association of gut microbiome and oral cavity cancer: A two sample mendelian randomization and case-control study

Effect of the oral microbiota, blood metabolome, and inflammatory proteins on oral cavity cancer: A bidirectional two-sample Mendelian randomization study and mediation analysis

OBJECTIVE

Oral Cavity Cancer (OCC) pathogenesis is complex, extending beyond traditional risk factors. While observational studies link oral microbiome dysbiosis, metabolic disturbances, and inflammation to OCC, inherent confounding limits causal inference regarding the putative 'microbiome-metabolite-inflammation' axis in OCC. Establishing causality is crucial.

METHODS

We employed a two-sample Mendelian randomization (MR) framework using large-scale GWAS data to address this gap. We systematically evaluated causal effects of 43 oral microbial taxa, 1400 diverse circulating metabolites, and 91 inflammatory proteins on OCC risk. We performed univariable MR (UVMR) for direct effects, multivariable MR (MVMR) adjusting for interactions, and mediation MR dissecting causal pathways.

RESULTS

UVMR identified protective effects for Clostridiales (OR = 0.89) and Rothia sp. ASV0016 (OR = 0.91), and increased risk for Bacteroidales (OR = 1.09). Furthermore, 60 metabolites (e.g., glycohyocholate increasing risk; 16α-hydroxy DHEAS-3-sulfate decreasing risk) and two proteins (Cystatin D increasing risk, OR = 1.26; MCP-1 decreasing risk, OR = 0.69) showed causal links to OCC. Crucially, mediation analyses indicated protective microbial effects were partially mediated via specific metabolites, including 5α-androstan-3α,17β-diol disulfate (Clostridiales) and carboxyethyl-GABA (Rothia sp.).

CONCLUSIONS

This study provides robust genetic evidence supporting causal roles for specific oral microbes and metabolites in OCC etiology. It offers mechanistic insights into the 'oral microbiome-host metabolism' axis, providing a basis for novel microbiome/metabolite-based biomarkers for early detection and risk assessment, and identifying potential preventative or therapeutic targets.

Plasma proteins mediate the effects of the gut microbiota on the development of head and neck cancer: a two-sample and mediated Mendelian randomized study

BACKGROUND

Although previous observational studies have highlighted a possible association between the gut microbiota (GM) and head and neck cancer (HNC), the causal relationships remain unclear, particularly regarding the role of plasma proteins as potential mediators. Clarifying these connections is essential for uncovering the underlying mechanisms of HNC progression and may lead to new therapeutic strategies.

MATERIALS AND METHODS

First, we examined the causal link between the GM and HNC via a two-sample Mendelian randomization (MR) approach. We then investigated the causative relationships between plasma proteins and HNC via the same two-sample MR technique. The coefficient product approach was then used to clarify the role of plasma proteins in the causative pathway between the GM and HNC. Finally, sensitivity investigations were performed to assess the robustness and coherence of the results.

RESULTS

MR analyses revealed the protective effects of one family and six genera on HNC (Lachnospiraceae, Parabacteroides, Phascolarctobacterium, Alistipes, Sutterella, Roseburia and Alloprevotella). In contrast, three genera (Ruminococcus, Prevotella and Bacteroides) were significantly positively associated with HNC risk. Through further examination, researchers discovered 18 plasma proteins that have a causal relationship with HNC. Notably, the mediation MR illustrated that the causal protective effect of OTU97_86 (Phascolarctobacterium) on HNC (total effect IVW: OR = 0.879, 95% = 0.810-0.954, p = 0.002) was mediated by Proteasome subunit alpha type-1 (PSMA1) (- 0.020, 95% CI = - 0.039 ~ - 0.001, p = 0.036), accounting for 15.25% of the total effect. Similarly, the causal effect of OTU99_35 (Ruminococcus) on HNC risk (total effect IVW: OR = 1.109, 95% CI = 1.027-1.198, p = 0.008) was mediated by the protein FAM107B (0.015, 95% CI = 0.001-0.029, p = 0.031), accounting for 14.69% of the total effect.

CONCLUSION

MR and mediation analysis revealed that specific GMs influence HNC risk through plasma proteins: Phascolarctobacterium protects against HNC via PSMA1, whereas Ruminococcus increases HNC risk through FAM107B. These pathways suggest that Phascolarctobacterium is a potential preventative factor and that Ruminococcus is a risk factor. This highlights the possibility of using specific GM and plasma proteins as biomarkers or therapeutic targets for HNC prevention, diagnosis, and treatment.

Unravelling the prognostic and operative role of intratumoural microbiota in non-small cell lung cancer: Insights from 16S rRNA and RNA sequencing

BACKGROUND

Complex interrelationships between the microbiota and cancer have been identified by several studies. However, despite delineating microbial composition in non-small cell lung cancer (NSCLC), key pathogenic microbiota and their underlying mechanisms remain unclear.

METHODS

We performed 16S rRNA V3-V4 amplicon and transcriptome sequencing on cancerous and adjacent normal tissue samples from 30 patients with NSCLC, from which clinical characteristics and prognosis outcomes were collected. We used 16S rRNA sequencing to dissect microbial composition and perform prognosis correlations, and in conjunction with transcriptome sequencing, we determined potential mechanisms underpinning significant microbiota actions.

RESULTS

In comparing different sample types, we identified more pronounced beta diversity disparity between NSCLC, lung squamous cell carcinoma (LUSC) and corresponding paired normal tissues. Concurrently, LUSC and lung adenocarcinoma exhibited distinct microbial composition traits at genus levels. Subsequently, four phyla, five classes, nine orders, 17 families and 36 genera were filtered out and were related to prognosis outcomes. Intriguingly, a protective microbial cluster was identified encompassing nine genera associated with delayed disease recurrence, with functional analyses suggested that these microbiota predominantly exerted metabolism-related functions. Additionally, a harmful microbial cluster (HMC) was identified, including three genera. In this HMC and subsequent prognosis model analyses, harmful intratumoural microbiota were potentially implicated in infection, inflammation and immune regulation. Crucially, we identified a microbial genus, Peptococcus, which was as an independent, detrimental NSCLC prognostic factor and potentially impacted prognosis outcomes via tumour necrosis factor (TNF) signalling.

CONCLUSIONS

We identified a substantial connection between intratumoural microbiota and NSCLC prognosis outcomes. Protective microbiota primarily exerted metabolic functions, whereas harmful microbiota were mainly implicated in infection, inflammation and immune modulation. Furthermore, Peptococcus may be significant in adverse NSCLC prognoses and serve as a potential biomarker for patient management and cancer screening.

KEY POINTS

Four phyla, five classes, nine orders, 17 families and 36 genera have been found associated with NSCLC prognosis. We identified a protective microbial cluster associated with delayed recurrence and a harmful microbial cluster related to shorter survival and earlier recurrence. We identified Peptococcus as an independent, detrimental prognostic factor for NSCLC, potentially impacting prognosis via TNF signalling.

A two-step, two-sample Mendelian randomization analysis investigating the interplay between gut microbiota, immune cells, and melanoma skin cancer

This study aims to rigorously explore the potential causal relationships among gut microbiota (GM), immune cells, and melanoma skin cancer among participants from Europe, where this disease exhibits significant prevalence and profound societal impact. Using the genome-wide association analysis database, a double-sample Mendelian randomization (MR) analysis was drawn upon to investigate GM, immune cells, and melanoma skin cancer. The inverse variance weighted approach was applied to estimate the causal connections among these variables. A two-step MR analysis was employed to quantitatively gauge the impact of immune cells mediated GM on melanoma skin cancer. To address potential sources of bias, such as pleiotropy and heterogeneity, multiple analytical techniques were integrated. The MR analysis pinpointed 6 GM taxa related to either an augmented or declined risk of late-stage melanoma skin cancer. In the same vein, 32 immune cell phenotypes were noticed as correlates with modified risk of melanoma skin cancer. Our study also implies that the probable association between GM and melanoma could be facilitated by 5 immune cell phenotypes. The findings of our study underline certain GM taxa and immune cells as potential influencers on the onset and development of melanoma skin cancer. Importantly, our results spotlight 5 immune cell phenotypes as potential agents mediating this association.

A study on the causal relationship between the gut microbiome and herpes zoster using Mendelian randomization

Introduction

The relationship between herpes zoster recurrence and the gut microbiome was not studied. We analyzed data on the gut microbiome and herpes zoster from the Large-Scale Genome-Wide Association Study (GWAS) database using bidirectional Mendelian randomization. For the first time, we identified a potentially bidirectional causal relationship between the gut microbiome and herpes zoster (HZ). These findings are groundbreaking and hold promise for new directions in the treatment of HZ, a global disease.

Background and aims

HZ had a high global incidence, characterized by shingled blisters, blood blisters, and neuropathic pain, and could develop in various parts of the body, including the ear and throat. It was believed its onset was closely related to old age and infirmity. Some studies reported that the incidence of herpes zoster in patients with inflammatory intestinal diseases (such as Crohn's disease and ulcerative colitis) was higher than in the general population. Existing studies attributed this to the reactivation of varicella-zoster virus (VZV) due to autoinflammatory attacks and immunosuppressive drugs. This provided a basis for exploring the new pathogenesis of HZ and investigating whether there was a relationship between intestinal auto-flora and the development of HZ. This study aimed to examine this potential relationship using bidirectional Mendelian analyses.

Methods

GWAS data on HZ and gut microbiota were obtained from FinnGen, the Mibiogen consortium, and HZ meta-analysis data from the IEU Open GWAS Project. These data were subjected to two-sample Mendelian randomization (MR) analysis to determine if there is a causal relationship between gut microbiota and HZ. Additionally, bidirectional Mendelian analyses were conducted to identify the direction of causality and to clarify any potential interactions.

Results

In our Mendelian Randomization (MR) analysis, we identified, for the first time, two gut microbes that might be associated with HZ reactivation. In the reverse MR analysis, four gut microbiota showed a potential association between the genetic susceptibility of gut microbiota and HZ reactivation. We found that genus Tyzzerella3 (OR: 1.42, 95% CI: 1.17-1.72, FDR < 0.1) may be strongly correlated with an increased probability of HZ (ICD-10: B02.901) reactivation. Additionally, phylum Cyanobacteria was identified as a potential risk factor for the onset of HZ rekindling (OR: 1.42, 95% CI: 1.09-1.87). Analyzing the results of the reverse MR, we also identified a potential inhibitory effect (OR: 0.91, 95% CI: 0.84-0.99) of HZ onset on the genus Eubacteriumhallii group in the gut, suggesting that HZ might reduce its abundance. However, genus Escherichia/Shigella (OR: 1.11, 95% CI: 1.01-1.22), genus Veillonella (OR: 1.16, 95% CI: 1.04-1.30), and phylum Proteobacteria (OR: 1.09, 95% CI: 1.01-1.18) appeared to act as potential protective factors, indicating that the relative abundance and viability of these three bacteria increased in the HZ state.

Conclusion

We identified the influence of gut flora as a new causative factor for HZ reactivation. Additionally, we found that individuals suffering from HZ might potentially impact their gut flora. Specific bacterial taxa that could influence the onset and progression of HZ were identified, potentially providing new directions for HZ treatment.

Gut microbiota and oral cavity cancer: a two-sample bidirectional Mendelian randomization study

This study employs a two-sample bidirectional Mendelian randomization (MR) approach to systematically evaluate the causal relationship between gut microbiota and oral cavity cancer (OCC).

Objective

To address the challenge in establishing the causal relationship between gut microbiota and OCC, we applied a systematic MR analysis.

Methods

Utilizing GWAS data from the MiBioGen consortium (18,340 individuals) and UK Biobank (n = 264,137), we selected instrumental variables and employed MR-Egger, weighted median, IVW, and weighted mode analyses. Heterogeneity and pleiotropy were assessed using Cochran's Q test and MR-Egger intercept test.

Results

Our findings indicate, at the order level, Bacteroidales (OR = 0.9990, 95% CI = 0.9980-1.0000, P = 0.046), Burkholderiales (OR = 1.0009, 95% CI = 1.0001-1.0018, P = 0.033), and Victivallales (OR = 0.9979, 95% CI = 0.9962-0.9995, P = 0.037) exhibit causality on OCC in the Weighted median, IVW, and MR-Egger analyses, respectively. At the family level, Alcaligenaceae (OR = 1.0012, 95% CI = 1.0004-1.0019, P = 0.002) and Clostridiaceae1 (OR = 0.9970, 95% CI = 0.9948-0.9992, P = 0.027) show causality on OCC in IVW and MR-Egger analyses. At the genus level, Clostridiumsensustricto1 (IVW, OR = 0.9987, 95% CI = 0.9980-0.9995, P = 0.001; MR-Egger, OR = 0.9978, 95% CI = 0.9962-0.9995, P = 0.035), Desulfovibrio (IVW, OR = 1.0008, 95% CI = 1.0001-1.0015, P = 0.016), Eggerthella (IVW, OR = 0.9995, 95% CI = 0.9990-1.0000, P = 0.048), Eubacterium fissicatena group (IVW, OR = 1.0005, 95% CI = 1.0000-1.0009, P = 0.032), and Holdemanella (IVW, OR = 0.9994, 95% CI = 0.9989-0.9999, P = 0.018) are implicated in causing OCC in related analyses.

Conclusion

Our study identifies Burkholderiales order, Alcaligenaceae family, Desulfovibrio genus, and Eubacterium fissicatena group as causally increasing OCC risk. In contrast, Bacteroidales order, Victivallales order, Clostridiaceae1 family, Clostridiumsensustricto1 genus, Eggerthella genus, and Holdemanella genus are causally associated with a decreased OCC risk. However, further investigations are essential to delineate an optimal gut microbiota composition and unravel the underlying mechanisms of specific bacterial taxa in OCC pathophysiology.

The Causal Effect of Gut Microbiota and Plasma Metabolome on Lung Cancer and the Heterogeneity across Subtypes: A Mendelian Randomization Study

The causal effect and pathways of gut microbiota and plasma metabolome on lung cancer have been important topics for personalized medicine; however, the heterogeneity of lung cancer subtypes has not gained enough attention in previous studies. This study sought to employ a Mendelian randomization analysis to screen the specific gut microbiota and plasma metabolome, which may have a causal effect on lung cancer. We further extended our analysis to estimate the effects of these exposures on various pathological subtypes of lung cancer. Furthermore, a mediation analysis was performed to identify the potential pathway underlying the influence of microbiota and metabolites. Our study identified 13 taxa and 15 metabolites with a causal association with the overall risk of lung cancer. Furthermore, we found 8 taxa and 14 plasma metabolites with a causal effect on lung adenocarcinoma, 4 taxa and 10 metabolites with a causal effect on squamous cell lung carcinoma, and 7 taxa and 16 metabolites with a causal effect on SCLC. We also identified seven mediation pathways that could potentially elucidate the influence of these microbiota and metabolites on overall lung cancer or special subtypes. Our study highlighted the heterogeneity of the gut microbiome and plasma metabolome in a lung cancer subtype and elucidated the potential underlying mechanisms. This could pave the way for more personalized lung cancer prevention and treatment.