Phenome-Wide Scan Finds Potential Orofacial Risk Markers for Cancer

Exploring etiologic contributions to the occurrence of external apical root resorption

INTRODUCTION

External apical root resorption (EARR) is often an undesirable sequela of orthodontic treatment. Prior studies have suggested a substantial link between EARR and certain genetic components. Single nucleotide polymorphisms (SNPs) may play a role as predisposing factors. This study aimed to investigate the potential association between EARR and various SNPs.

METHODS

The study included 218 orthodontic participants of all malocclusions who had available pretreatment and posttreatment panoramic radiographs. The most severely affected maxillary incisor on the radiograph was assessed for EARR using a 0-4 categorical scale. DNA was taken from the saliva samples of the participants, and the SNPs were analyzed using polymerase chain reaction and TaqMan chemistry. Statistical testing was performed to verify any associations with EARR (P <0.05).

RESULTS

From all genes tested, the rs678397 SNP of ACT3N (P = 0.003) and the rs1051771 SNP of TSC2 (P = 0.03) were significantly associated with EARR. No association could be established between other polymorphisms and EARR. In addition, patients with Class III malocclusion and extended treatment times were at increased risk of developing EARR.

CONCLUSIONS

Our results support the concept of gene polymorphisms as risk factors in EARR. In particular, a significant association was found between ACT3N and TSC2 and EARR. Clinically, predisposing risk factors for EARR should be assessed for each patient.

The salivary microbiota of patients with acute lower respiratory tract infection-A multicenter cohort study

The human microbiome contributes to health and disease, but the oral microbiota is understudied relative to the gut microbiota. The salivary microbiota is easily accessible, underexplored, and may provide insight into response to infections. We sought to determine the composition, association with clinical features, and heterogeneity of the salivary microbiota in patients with acute lower respiratory tract infection (LRTI). We conducted a multicenter prospective cohort study of 147 adults with acute LRTI presenting to the emergency department of seven hospitals in three states (Pennsylvania, Michigan, and Ohio) between May 2017 and November 2018. Salivary samples were collected in the emergency department, at days 2-5 if hospitalized, and at day 30, as well as fecal samples if patients were willing. We compared salivary microbiota profiles from patients to those of healthy adult volunteers by sequencing and analyzing bacterial 16-rRNA. Compared to healthy volunteers, the salivary microbiota of patients with LRTI was highly distinct and strongly enriched with intestinal anaerobes such as Bacteroidaceae, Ruminococcaceae, and Lachnospiraceae (e.g., mean 10% relative abundance of Bacteroides vs < 1% in healthy volunteers). Within the LRTI population, COPD exacerbation was associated with altered salivary microbiota composition compared to other LRTI conditions. The largest determinant of microbiota variation within the LRTI population was geography (city in which the hospital was located).

An updated review on the link between oral infections and atherosclerotic cardiovascular disease with focus on phenomics

Atherosclerotic cardiovascular diseases (ACVD) and oral infections such as periodontal disease, dental caries, and apical periodontitis are diseases that affect a great portion of the worldwide population. Both are complex in nature and several studies show that they share etiological factors but a causal relationship between them has not been yet established due to the lack of well-designed clinical trials. Many studies in the recent years show convincing evidence of different mechanisms that might be involved in this association including chronic inflammation and immune response. However, some of these mechanisms are controversial because of confounding factors. It has been suggested that maladaptive inflammatory reactivity, determined in part by single nucleotide polymorphisms (SNPs) in pathway genes, could influence the association between oral infections, and cardiovascular diseases as pleiotropic genes. That is, these conditions could be outcomes of similar inflammatory pathways. Phenomics, the study of the changes in phenotypes or traits considering environmental variables and genetics is efficient in assessing and determining pleiotropic genes. Future research should focus on analyzing a combination of oral inflammatory conditions instead of focusing on one inflammatory phenotype alone and consider pleiotropy as a mechanistic contributor for these associations. Further, prospective observational studies seeking to follow the development of oral disease and subclinical ACVD will foster the understanding of the impact of oral health on general systemic health. Lastly, to demonstrate that oral infections would increase risk for subclinical ACVD development, clinical trials proposing to treat those infections considering genetic background and all other confounders are needed.

Genetic contribution to cancer risk in patients with tooth loss: a genetic association study

Early-stage cancer diagnosis is critical for higher survival rates. Because early cancers can be difficult to detect, our focus is on the identification of cancer risk markers such as pleiotropic genes involved in the etiology of both craniofacial conditions and cancers. In this study we aimed to test if our previously detected association between ERN1 rs196929 marker and oral health outcomes would be detected in individuals diagnosed with cancer as well as in a subpopulation of individuals who also had one or more teeth missing due to dental caries, periodontal disease, or periapical lesions. We genotyped a total of 1,671 subjects and selected a subset of 1,421 subjects for stratified analysis of cancer types; three hundred and twelve self-reported a diagnosis of various cancer types and 1,109 reported never receiving a diagnosis of cancer. Our results showed a statistically significant association between the rs196929 in ERN1, and cancer overall in both the additive and dominant models (OR = 1.37, 95% C.I. 1.06-1.79, p = 0.014). When we stratified the analysis for each cancer type, our results show that the rs196929 ERN1 variant is associated with skin cancer (OR = 2.07, 95% C.I. 1.27-3.37, p = 0.003) and breast cancer (OR = 1.83, 95% C.I. 1.13-2.99, p = 0.013) in the subset of patients that had tooth loss. An additional nominal association between the rs196929 in ERN1 and male's reproductive system cancers (OR = 1.96, 95% C.I. 1.07-3.59, p = 0.028) was identified. We hope that our study helps guide future genetic studies on these cancers and this specific genetic variant as well as drive attention to the potential for oral health outcomes to serve as indicators for cancer risk. The early identification of genetic markers and/or oral conditions that indicate increased cancer risk could positively impact cancer outcomes and survival rates with timely implementation of preventive and diagnostic measures. In conclusion, our results suggest that the genetic variant in ERN1 (rs196929) is associated with increased risk of skin and breast cancers.

Phenome-Wide Association Study With Focus on Oral Health Disparities and Individuals Who Did Not Have Cancer

The goal of this study was to test if oral health outcomes are associated with the same genetic markers in Black and White individuals who did not have cancer. From a total of 6,100 subjects from the Dental Registry and DNA Repository project, 1,042 individuals who self-identified as White and 266 as Black without a history of cancer were included in this analysis. Genotyping data from IRE1—rs196929, RHEB—rs2374261 and rs1109089, AXIN2—rs2240308 and rs11867417, and RPTOR—rs4396582, present in cell regulatory pathways, were analyzed. We ran separate analyses in self-reported Black and White groups to reduce possible confounding effects of population stratification. Internal diagnostic codes from our dental registry were converted into Phecodes in order to run the analysis using the PheWAS package, installed in R Studio software. Periodontitis was associated with RHEB in both Black and White patients, with the minor allele increasing the likelihood of developing periodontitis in the White group and yielding a protective effect in the Black individuals. The presence of ulcers and gingivitis were associated with RPTOR and AXIN2, respectively, in the White group, but an association was not detected for the Black group. On the other hand, phenotypes such as dental fracture, diseases of the tongue, attrition, erosion, abrasion, fordyce granules, and torus and exostosis were uniquely associated with the Black group. Periodontitis associated with RHEB in both Black and White patients, and associations found in Black individuals may be the result of social disparities that lead to higher levels of stress, and these observed differences require further study.

Biomarkers for Lifetime Caries-Free Status

The purpose of this study was to address the hypothesis that extreme outcomes of dental caries, such as edentulism or prematurely losing permanent teeth are associated with genetic variation in enamel-formation genes. After scanning 6206 individuals, samples of 330 were selected for this study. Tested phenotypes included patients who were edentulous by age 30, patients with missing first molars by age 30, patients with missing second molars by age 30, and caries-free patients. Fourteen single nucleotide polymorphisms were genotyped by TaqMan chemistry. The analyses of each phenotype were performed using the software PLINK with an alpha of 0.05. Nominal associations were found between rs12640848 in enamelin (p = 0.05), rs1784418 in matrix metallopeptidase 20 (p = 0.02), and rs5997096 in the tuftelin interacting protein 11 and being caries-free at the age of 60. When combining patients that were missing both first mandibular molars and missing both second mandibular molars, no associations were found. Matrix metallopeptidase 20, and tuftelin interacting protein 11 also showed trends for association with being caries-free. Genetic variation in TFIP11, MMP20, and ENAM may have a protective effect increasing the chances of individuals preserving their teeth caries-free over a lifetime.