How your genes influence the microbes and cavities in our mouth

Amazing stuff!

"Highlights

• A new study suggests that our genetics plays a role in determining the microbial community living in our mouths.
• Scientists discovered 11 regions of the human genome that influence the abundances of dozens of bacterial species in the mouth.
• The authors found a relationship between a human gene and oral bacteria that plays a role in dental health.

...

found a surprisingly large effect of human genetics on the abundance of microbes in the mouth. The researchers discovered genome-to-genome interactions between human DNA and the DNA of the oral microbiome. For example, they found that a human gene, AMY1, was strongly linked to the composition of the oral microbial community, and even to dentures use, suggesting that the relationship between this gene and the bacteria in the mouth plays a role in oral health. ..."

From the abstract:

"Human genetic variation influences all aspects of our biology, including the oral cavity, through which nutrients and microbes enter the body. Yet it is largely unknown which human genetic variants shape a person’s oral microbiome and potentially promote its dysbiosis.

We characterized the oral microbiomes of 12,519 people by re-analysing whole-genome sequencing reads from previously sequenced saliva-derived DNA. Human genetic variation at 11 loci (10 new) associated with variation in oral microbiome composition.

Several of these related to carbohydrate availability; the strongest association (P = 3.0 × 10−188) involved the common FUT2 W154X loss-of-function variant, which associated with the abundances of 58 bacterial species.

Human host genetics also seemed to powerfully shape genetic variation in oral bacterial species: these 11 host genetic variants also associated with variation of gene dosages in 68 regions of bacterial genomes. Common, multi-allelic copy number variation of AMY1, which encodes salivary amylase, associated with oral microbiome composition (P = 1.5 × 10−53) and with dentures use in UK Biobank (P = 5.9 × 10−35, n = 418,039) but not with body mass index (P = 0.85), suggesting that salivary amylase abundance impacts health by influencing the oral microbiome.

Two other microbiome composition-associated loci, FUT2 and PITX1, also significantly associated with dentures risk, collectively nominating numerous host–microbial interactions that contribute to tooth decay."

How genes influence the microbes in our mouths | Broad Institute "Analysis of the now largest collection of oral microbiome profiles reveals interactions between human and bacterial DNA. "

Human and bacterial genetic variation shape oral microbiomes and health (open access)

Fig. 1: Oral microbiomes in 12,519 individuals measured by WGS [whole-genome sequencing] of saliva samples.

27 oral microbes linked to a greater risk of developing pancreatic cancer by 3.5 times

Amazing stuff! Cancer is history (soon)!

Does a daily mouthwash with antiseptics help? We need another study! 😊

"For the first time, scientists have identified 27 bacteria and fungi living in our mouths that are implicated in the development of pancreatic cancer. Collectively, housing all of the bad microbes increases one’s risk of the deadly disease by 250% – or 3.5 times higher – compared to the general population.

Researchers ... sampled the saliva of 122,000 healthy US men and women, who took part in the American Cancer Society Cancer Prevention Study II and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Samples were collected at baseline, and participants were followed for an average of nine years, with any records of tumors added to the data. ..."

"Among the hundreds of species of bacteria and fungi that live in people’s mouths, 27 have been collectively tied to a 3.5 times greater risk of developing pancreatic cancer ...

Experts have long observed that those with poor oral health are more vulnerable to pancreatic cancer than those with healthier mouths. More recently, scientists have uncovered a mechanism that could help explain this connection, finding that bacteria can travel through swallowed saliva into the pancreas, an organ that helps with digestion. ...

Last year, the same team of scientists uncovered a link between certain oral bacteria and a heightened risk of developing head and neck squamous cell carcinoma, a group of cancers that arise in the mouth and throat.

The researchers had also conducted a small study in 2016 that tied microbes living in the mouth to pancreatic cancer, but could not identify precise bacterial species. ..."

From the key points and abstract:

"Key Points

Question

Is the prediagnostic oral bacterial and fungal microbiome associated with the subsequent development of pancreatic cancer?

Findings

In this cohort study including 122 000 individuals, 3 oral bacterial periodontal pathogens, an additional 20 bacteria, and 4 fungi were identified, which together conferred a more than 3-fold increase in the risk for pancreatic cancer.

Meaning

The oral fungal and bacterial microbiotas may serve as readily accessible, noninvasive biomarkers for subsequent pancreatic cancer risk to identify individuals at high risk of pancreatic cancer.

Abstract

Importance

The oral microbiota may be involved in the development of pancreatic cancer, yet current evidence is largely limited to bacterial 16S amplicon sequencing and small retrospective case-control studies.

Objective

To test whether the oral bacterial and fungal microbiome is associated with the subsequent development of pancreatic cancer.

Design, Setting, and Participants

This cohort study used data from 2 epidemiological cohorts: the American Cancer Society Cancer Prevention Study-II Nutrition Cohort and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Among cohort participants who provided oral samples, those who prospectively developed pancreatic cancer were identified during follow-up.

Control participants who remained free of cancer were selected by 1:1 frequency matching on cohort, 5-year age band, sex, race and ethnicity, and time since oral sample collection.

Data were collected from August 2023 to September 2024, and data were analyzed from August 2023 to January 2025.

Exposures

The oral bacterial and fungal microbiome were characterized via whole-genome shotgun sequencing and internal transcribed spacer (ITS) sequencing, respectively.

The association of periodontal pathogens of the red complex (Treponema denticola, Porphyromonas gingivalis, and Tannerella forsythia) and orange complex (Fusobacterium nucleatum, F periodonticum, Prevotella intermedia, P nigrescens, Parvimonas micra, Eubacterium nodatum, Campylobacter shower, and C gracilis) with pancreatic cancer was tested via logistic regression.

The association of the microbiome-wide bacterial and fungal taxa with pancreatic cancer was assessed by Analysis of Compositions of Microbiomes With Bias Correction 2 (ANCOM-BC2).

Microbial risk scores (MRS) for pancreatic cancer were calculated from the risk-associated bacterial and fungal species.

Main Outcomes and Measures

Pancreatic cancer incidence.

Results

Of 122 000 cohort participants who provided samples, 445 developed pancreatic cancer over a median (IQR) follow-up of 8.8 (4.9-13.4) years and were matched with 445 controls.

Of these 890 participants, 474 (53.3%) were male, and the mean (SD) age was 67.2 (7.5) years.

Three oral bacterial periodontal pathogens—P gingivalis, E nodatum, and P micra—were associated with increased risk of pancreatic cancer.

A bacteriome-wide scan revealed 8 oral bacteria associated with decreased and 13 oral bacteria associated with increased risk of pancreatic cancer (false discovery rate–adjusted Q statistic less than .05).

Of the fungi, genus Candida was associated with increased risk of pancreatic cancer.

The MRS, based on 27 oral species, was associated with an increase in pancreatic cancer risk (multivariate odds ratio per 1-SD increase in MRS, 3.44; 95% CI, 2.63-4.51).

Conclusions and Relevance

In this cohort study, oral bacteria and fungi were significant risk factors for pancreatic cancer development. Oral microbiota hold promise as biomarkers to identify individuals at high risk of pancreatic cancer, potentially contributing to personalized prevention."

Oral bacteria linked to higher pancreatic cancer risk "27 oral microbes drive 250% rise in pancreatic cancer risk"

Oral Microbes Linked to Increased Risk of Pancreatic Cancer

Oral Bacterial and Fungal Microbiome and Subsequent Risk for Pancreatic Cancer (no public access)