Is there a relationship between periodontal disease and oral cancer? A systematic review of currently available evidence

The Highly Pure Neem Leaf Extract, SCNE, Inhibits Tumorigenesis in Oral Squamous Cell Carcinoma via Disruption of Pro-tumor Inflammatory Cytokines and Cell Signaling

Oral squamous cell carcinoma (OSCC) is a deadly disease that comprises 60% of all head and neck squamous cell cancers. The leaves of the Neem tree (Azadirachta indica) have been used in traditional Ayurvedic medicine for centuries to treat numerous oral maladies and are known to have significant anti-inflammatory properties. We hypothesize that a highly pure super critical CO2 Neem leaf extract (SCNE) prevents initiation and progression of OSCC via downregulation of intra-tumor pro-inflammatory pathways, which promote tumorigenesis. Hence, we investigated the anticancer effects of SCNE using in vitro and in vivo platforms. OSCC cell lines (SCC4, Cal27, and HSC3) were treated with SCNE while inflammation, proliferation, and migration were analyzed over time. SCNE treatment significantly inhibited OSCC cell proliferation and migration and reduced MMP activity in vitro, suggesting its potential to inhibit tumor growth and metastasis. The preventive effects of SCNE in ectopic xenograft and 4NQO-1 (4-Nitroquinoline-1-oxide) carcinogen-induced mouse models of OSCC were also evaluated. Indeed, xenografted nude mice showed significant reduction of OSCC tumor volumes. Likewise, SCNE significantly reduced the incidence of tongue dysplasia in the 4NQO-1 OSCC initiation model. In both OSCC animal models, SCNE significantly depressed circulating pro-cancer inflammatory cytokines (host and tumor-secreted) including NFkB, COX2, IL-1, IL-6, TNFα, and IFNγ. In addition, we demonstrate that SCNE downregulates STAT3 and AKT expression and activity in vitro. We also demonstrate that the primary active component, nimbolide (NIM), has significant anticancer activity in established OSCC xenografts. Lastly, we show that SCNE induces an M1 phenotype in tumor associated macrophages (TAMS) in vivo. Taken together, these data strongly support SCNE as means of preventing OSCC via downregulation of pro-cancer inflammatory cascades and NIM as a potential new therapy for existing OSCC.

Awareness of the Relationship between Systemic and Periodontal Diseases among Physicians and Dentists in Saudi Arabia and Kuwait: Cross-sectional Study

Background:

Previous studies have shown possible association between periodontal diseases and Diabetes Mellitus (DM), Cardiovascular Disease (CVD) and Adverse Pregnancy Outcomes (APO). Increasing the knowledge of physicians and dentists regarding the association between periodontal disease and systemic diseases should improve their ability to provide a high standard of treatment for the disease and prevent its consequences. In our study, we sought to identify knowledge gaps in the awareness of the relationship between systemic and periodontal diseases among dentists and physicians from the Kingdom of Saudi Arabia and the State of Kuwait.

Methods:

A cross-sectional study was performed with a convenient sample of selected physicians and dentists in Saudi Arabia and Kuwait using a self-developed structured questionnaire. Physicians’ and dentists’ awareness were assessed regarding current evidence of the relationship between systemic diseases and conditions (DM, CVD, APO) and periodontal diseases.

Results:

A total of 134 (21.5%) of the identified physicians and 485 (78%) of the identified dentists participated in this study. More than half of the participants (52.1% physicians and 67.5% dentists) agreed that there is a relationship between periodontal diseases and DM, CVD and APO. Dentists had a statistically higher level of awareness compared with the physicians. The findings related to the awareness of the dentist sub groups highlighted that periodontists were significantly more likely to have a good level of knowledge.

Conclusion:

Within the limitations of this study, we concluded that the awareness of physicians and dentists regarding the relationship between periodontal diseases and systemic diseases (DM, CVD, APO) is generally low, Therefore, improved collaboration between medical and dental health providers is recommended.

[Aetiopathology and prevention of oropharyngeal cancer]

Oropharyngeal cancer is in the sixth position of cancer incidence in the world (after colorectal, breast, prostate, bladder, and cervix uteri cancer). More than 90% of them are squamous cell carcinoma. This type of cancer can originate on the lip, oral cavity, pharynx, and larynx. The risk factors associated with oropharyngeal cancer are tobacco, alcohol, and poor oral hygiene. However, other conditions, such as infection with human papilloma virus (HPV) and oral dysbiosis, are gaining prominence. Pre-malignant and malignant lesions are related to diverse factors that can be monitored by the health professional. These professionals are also in an ideal position to influence and advise patients on healthy life habits that contribute to prevent or treat metabolic-endocrine syndromes associated with the development of pre-cancerous disease and cancer located in different organs.

Effect of tobacco on periodontal disease and oral cancer

INTRODUCTION

Periodontal disease and oral cancer are common health hazards. Epidemiological investigations show that smoking, periodontal disease and oral cancer are closely related. Tobacco is one of the major risk factors for periodontitis and oral cancer.

METHODS

A systematic literature review was performed. To identify relevant studies, the following online databases were searched using specific keywords: PubMed, Web of Science and CNKI.

RESULTS

Tobacco not only possesses an addictive effect, but it aggravates periodontal disease by promoting the invasion of pathogenic bacteria, inhibiting autoimmune defense, aggravating the inflammatory reaction, and aggravating the loss of alveolar bone. According to current evidence, tobacco significantly aggravates the development and progression of periodontal disease and oral cancer, and periodontal disease may be related to the prevalence of oral cancer.

CONCLUSIONS

Clinicians should strongly recommend that smokers undertake a strategy to stop smoking to avoid the exacerbation of nicotine-related periodontal disease and to reduce the incidence of oral cancer.

Dysregulated Phosphate Metabolism, Periodontal Disease, and Cancer: Possible Global Health Implications

An association between periodontal disease and cancer has been established in recent studies, but no common etiology has been identified in the hopes of reducing the global burden of these non-communicable diseases. This perspective article hypothesizes that the determinant mediating the association of periodontal disease with cancer is dysregulated phosphate metabolism. Phosphate, an essential dietary micronutrient, is dysregulated in chronic kidney disease, and both cancer and periodontal disease are associated with chronic kidney disease. Reviewed evidence includes the association between phosphate toxicity and cancer development, and the association between periodontal disease and chronic kidney disease-mineral and bone disorder includes conditions such as ectopic calcification and bone resorption, which may be indirectly related to periodontal disease. Dental calculus in periodontal disease contains calcium phosphate crystals that are deposited from excess calcium and phosphate in saliva. Alveolar bone resorption may be linked systemically to release of parathyroid hormone in response to hypocalcemia induced by hyperphosphatemia. More research is needed to examine the role of dysregulated phosphate metabolism in periodontal disease.

Guidelines for the Surgical Management of Oral Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to provide guidance on the implementation of a surgical treatment of oral cancer. MEDLINE databases were searched for articles on subjects related to “surgical management of oral cancer” published in English. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. The quality of evidence was rated with use RoBANS (Risk of Bias Assessment Tool for Nonrandomized Studies) and AMSTAR (A Measurement Tool to Assess the Methodological Quality of Systematic Reviews). Evidence-based recommendations for practice were ranked according to the American College of Physicians grading system. Additional directives are provided as expert opinions and Delphi questionnaire when insufficient evidence existed. The Committee developed 68 evidence-based recommendations in 34 categories intended to assist clinicians and patients and counselors, and health policy-makers. Proper surgical treatment selection for oral cancer, which is directed by patient- and subsite-specific factors, remains the greatest predictor of successful treatment outcomes. These guidelines are intended for use in conjunction with the individual patient’s treatment goals.

Calculus and survivorship in medieval London: The association between dental disease and a demographic measure of general health

OBJECTIVES

Dental plaque is associated with a variety of systemic diseases and mortality risks in living populations. However, bioarchaeologists have not fully investigated the mortality risks associated with plaque (or its mineralized form, calculus) in the past. This study examines the relationship between survivorship and calculus in a medieval skeletal sample.

MATERIALS AND METHODS

Our sample (n = 1,098) from four medieval London cemeteries, c. 1000-1540 CE, includes people who died under attritional (normal) and catastrophic (famine and plague) conditions. The associations between age and the presence of dental calculus on the permanent left first mandibular molar are assessed using binary logistic regression and Kaplan-Meier survival analysis.

RESULTS

The regression results indicate a significant negative relationship between age and calculus presence for individuals of all ages who died under normal mortality conditions and for adults who died under both normal and catastrophic conditions. Survival analysis reveals decreased survivorship for people of all ages with calculus under normal mortality conditions. Similarly, during conditions of catastrophic mortality, adult males with calculus suffered reduced survivorship compared to males without it, though there was no difference in survivorship between adult females with and without calculus.

CONCLUSIONS

These results suggest that, as in modern populations, calculus accumulation in the inhabitants of medieval London reflects a greater risk of premature death. The evaluation of calculus, a potential measure of underlying frailty, in the context of a demographic measure of general health suggests that it might provide insights into health in past populations.

Evidence for chronic mechanical irritation as a causative factor in oral cancer: application of Bradford Hill criteria

Chronic mechanical irritation (CMI) of the oral mucosa has been proposed as a risk factor for oral cancer (OC), but the available evidence is limited and controversial. One of the main limitations is the lack of proper criteria to define and classify CMI. The objective of this narrative review is to apply the Bradford Hill causality criteria to assess such an association based on the published literature. The level of evidence is not conclusive, mainly due to methodological shortcomings. Hence, to systematize future CMI research, we recommend the following items should be included: a clear definition for CMI, ascertaining any temporal association, recording all types of CMI: dental, prosthetic, and functional. Finally, it is important to emphasize that studies dealing with risk factors for OC should not only be restricted to established factors such as tobacco, alcohol, and areca nut consumption but should also consider other factors including the patient’s dental condition. In this regard, CMI, tooth loss, periodontal disease, and many others could be included. The causality criteria set out by Bradford Hill could be used for studying different controversial risk factors for OC.

Oral Health of Korean Patients With Head and Neck Cancer

Background

Association between periodontitis and of head and neck carcinoma was suggested. In the present study, we evaluated the oral health status of patients with head and neck carcinoma and analyzed the relationship between cancer characteristics and oral health.

Methods

Oral health of 40 patients with head and neck carcinoma was examined. Decayed teeth, missing teeth, plaque index, gingival index, and probing depth were measured. Cancer type and site were recorded based on the patients' medical records.

Results

The average age of participants was 60.10 ± 8.99 years, and 35 of participants were male. The decay or missing teeth index was 5.43 ± 5.57, and the plaque index, gingival index, and probing depth were 1.37 ± 1.03, 1.57 ± 0.84, and 4.13 ± 1.45, respectively. These indexes showed no significant difference according to the type or site of cancer (P > 0.05).

Conclusions

This study showed that there was no correlation between oral health parameters and characteristics of head and neck carcinoma.

Is periodontitis a risk indicator for cancer? A meta-analysis

Background

The aim of the present systematic review was to evaluate the hypothesis of an association between periodontitis and the development of cancer.

Methods

Two reviewers independently screened electronic and manual sources for pertinent articles. Primary outcome measures were the occurrence of neoplasm diagnosis in exposed and non-exposed groups, reported to evaluate association between cancer and periodontitis.

Results

Of the 490 initially retrieved papers 10 were included in the qualitative synthesis and eight in the quantitative synthesis; the eight papers covered six studies. Considering hazard ratios, a statistically significant association was found for all cancers studied (1.14; CI 95%: 1.04, 1.24), digestive tract cancer (1.34; CI 95%: 1.05, 1.72), pancreatic cancer (1.74; CI 95%: 1.21, 2.52), prostate cancer (1.25; CI 95%: 1.04, 1.51), breast cancer (1.11; CI 95%: 1.00, 1.23), corpus uteri cancer (2.20; CI 95%: 1.16, 4.18), lung cancer (1.24; CI 95%: 1.06, 1.45), hematological cancer (1.30; CI 95%: 1.11, 1.53), esophagus / oropharyngeal cancer pooled together (2.25; CI 95%: 1.30, 3.90) and Non-Hodgkin lymphoma (1.30; CI 95%: 1.11, 1.52).

Conclusions

Despite the sparse scientific evidence and considering the low statistical power of the results, this systematic review revealed a substantial lack of studies with standardized and comparable methods to speculate about the association between periodontitis and cancer; more studies are need in order to explore further the scientific evidence of such correlation.

Periodontal Disease, Tooth Loss, and Cancer Risk

Periodontal disease, which includes gingivitis and periodontitis, is highly prevalent in adults and disease severity increases with age. The relationship between periodontal disease and oral cancer has been examined for several decades, but there is increasing interest in the link between periodontal disease and overall cancer risk, with systemic inflammation serving as the main focus for biological plausibility. Numerous case-control studies have addressed the role of oral health in head and neck cancer, and several cohort studies have examined associations with other types of cancers over the past decade. For this review, we included studies that were identified from either 11 published reviews on this topic or an updated literature search on PubMed (between 2011 and July 2016). A total of 50 studies from 46 publications were included in this review. Meta-analyses were conducted on cohort and case-control studies separately when at least 4 studies could be included to determine summary estimates of the risk of cancer in relation to 1) periodontal disease or 2) tooth number (a surrogate marker of periodontal disease) with adjustment for smoking. Existing data provide support for a positive association between periodontal disease and risk of oral, lung, and pancreatic cancers; however, additional prospective studies are needed to better inform on the strength of these associations and to determine whether other cancers are associated with periodontal disease. Future studies should include sufficiently large sample sizes, improved measurements for periodontal disease, and thorough adjustment for smoking and other risk factors.

Hepatitis C Infection and Periodontal Disease: Is there a Common Immunological Link?

Hepatitis C virus (HCV) infections could have an important impact on the oral health status of patients, favoring conditions such as periodontal disease and oral cancer. The review of the existing scientific literature written in English was performed, searching for oral and periodontal manifestations of HCV infection and its impact on the oral fluids. HCV infection can determine direct extrahepatic manifestations at the oral and periodontal level including oral lichen planus, Sjögren-like sialadenitis, and oral cancer. The changes caused by the infection in the subjects' immune system, diet, and lifestyle can facilitate the development of oral conditions such as periodontal disease. Important changes also occur in the composition of the infected patients' saliva and gingival fluid. HCV-infected patients need to be carefully monitored in terms of oral health since the infection with the virus can result in oral complications. The cellular and molecular particularities of the gingival fluid of HCV-infected patients can answer some questions regarding its impact upon periodontium impairment and whether this refers to a possible bidirectional relationship, with hepatic biomarker adjustments being induced by the periodontal patients' inflammatory status.

Spontaneous alveolar bone loss after 4NQO exposure in Wistar rats

OBJECTIVE

This study evaluated the effect of an experimental carcinogenic, 4-Nitroquinoline 1-oxide (4NQO), in the spontaneous alveolar bone loss (ABL) in an animal model.

DESIGN

Twenty-two male Wistar rats were included in this study. They were randomly divided into two groups: the control group (n = 10) received food and water ad libitum, and the test group (n = 12) receive the same food; however, 25 ppm of 4NQO was diluted in the drinking water. All animals were euthanized after 20 weeks, and the tongues were removed and analyzed macroscopically to determine the presence of oral mucosal lesions. All specimens were paraffin-embedded and histological sections were obtained. The microscopic analysis was based on routine procedure (haematoxylin and eosin stain). The analysis of spontaneous ABL was performed by a calibrated examiner using standardized photographs and imaging software. Differences in spontaneous ABL were assessed among the three resulting groups: control, 4NQO with oral squamous cell carcinoma (OSCC), and 4NQO without OSCC.

RESULTS

In the 4NQO-treated group, nine animals developed OSCC. The animals in the 4NQO with OSCC group presented significantly more spontaneous ABL (0.65 ± 0.21 mm) than the control group (0.34 ± 0.05) (p < 0.001). The animals in the 4NQO without OSCC group showed a mean spontaneous ABL of 0.47 ± 0.13 mm, which was not statistically significant different when compared to the control group (p = 0.096).

CONCLUSIONS

It was concluded that the presence of OSCC enhanced spontaneous ABL in Wistar rats when compared to control animals. Additionally, it was shown that, solely, administration of 4NQO may not be considered responsible for alveolar bone destruction.

Elder neglect-Oral diseases and injuries

Elder neglect (EN) is the failure of a designated caregiver to meet the needs of a dependent older person. World EN prevalence, meta-analyzed in this study, is 1.0% or 1.8% according to different statistical methods. Referring alleged EN cases to Adult Protective Services (APSs) by healthcare workers (HCWs) is mandatory in many countries. However, only few claims are substantiated, as EN could be confused with Self-Neglect, and neglect could be unintentional or due to caregiver unawareness. Screening tools are inaccurate, and their use is discouraged by public health organizations, because they lead to too many false positives, which engulf the already overwhelmed APSs. HCWs need effective tools with objective judgments, which do not hamper the HCW-caregiver-patient rapport and prevent lawsuits when allegations are unfounded. Orofacial EN manifestations (poor oral/denture hygiene, lack of needed/improper dentures, dry mouth, skin/mucosal rashes) are essential Forensic Markers of EN. I classified EN-associated oral diseases according to the unmet needs into four groups: (1) traumatic injuries due to lack of caregiver vigilance (e.g., maxillofacial fractures); (2) diseases due to oral hygiene deficiency (e.g., root caries); (3) diseases typical of the elderly with late/no diagnosis (e.g., oral cancer); and (4) diseases typical of the elderly exacerbated by psychological distress (e.g., oral lichen planus).

Ex corpore linguae: A cohort analysis after a unique surgical technique in oral cancer resection

OBJECTIVE

Resection of posteriorly located oral squamous cell carcinomas (OSCCs) remains challenging for head and neck surgeons. However, several surgical techniques, such as lip and mandibular splitting, as well as submental "visor drop-down" of intraoral soft tissues, have been proposed for this purpose. Merrick et al. suggested that a pedicled genial drop-down surgical approach should be used to resect dorsally located OSCCs. Our study investigated patient outcomes following this surgical procedure, as no previous study has analyzed long-term follow-up data.

MATERIAL AND METHODS

All patients who underwent surgery using the pedicled genial "visor drop-down" approach at the Maxillofacial Department of the University Hospital Giessen in Germany between 1995 and 2010 were included in this study. In addition, our study required that patients diagnosed with OSCC had no history of other intraoral malignancy or any other form of malignancy. A preliminary questionnaire was completed for each patient based on retrospective analysis of available data from medical reports.

RESULTS

A total of 51 patients fulfilled all inclusion and exclusion criteria and were evaluated retrospectively. In total, 32 patients were excluded from the study due to OSCC recurrence or acquisition of a different type of malignancy. The male to female distribution of patients in our study was 30 to 21 (58.8%-41.2%), and the mean ages of female and male patients were 57.7 (SD 14.3) and 55.7 (SD 14.4) years, respectively. Approximately 76.5% of tumors were located along the dorsal aspect of the tongue, 17.6% were along the floor of the mouth, 3.9% were in the dorsal mandibular region, and 1.9% were in the dorsal palatal region. The mean overall operation time was 6.25 h, and 28 patients received microvascular flaps for reconstruction. Results of final histopathological examination suggested primary in-sano resection of the tumor in 84.3% of patients. Overall, the 5-year postoperative survival rate was 52.9%; 31.3% of the patient cohort was not followed up for the full 5-year period. In addition, 15.7% of the patients included in our study died during the study period. Unimpaired functional outcomes in terms of swallowing and speech were observed in 86.3% of patients.

CONCLUSION

The pedicled genial "visor drop-down" approach, also known as the ex corpore linguae, is a suitable method for the radical resection of dorsally located OSCCs, with a promising 5-year survival rate and satisfactory postoperative oral function.

Increased cancer risk in patients with periodontitis

BACKGROUND

Previous studies have noted a possible association between periodontal diseases and the risk of various cancers. We assessed cancer risk in a cohort of patients with moderate to severe periodontitis.

METHODS

Patients diagnosed with moderate to severe periodontitis by a periodontist between 2001 and 2010 were identified from the hospital registry. Patients younger than 35 years of age or with a prior cancer diagnosis were excluded. The age- and gender-standardized incidence rates (SIR) were calculated by dividing the number of observed cases by the number of expected cases from Turkish National Cancer Registry 2013 data.

RESULTS

A total of 280 patients were included (median age 49.6, 54% female). Median follow-up was 12 years. Twenty-five new cancer cases were observed. Patients with periodontitis had 77% increased risk of cancer (SIR 1.77, 95% CI 1.17-2.58, p = .004). Women with periodontitis had significantly higher risk of breast cancer (SIR 2.40, 95% CI 0.88-5.33) and men with periodontitis had significantly higher risk of prostate cancer (SIR 3.75, 95% CI 0.95-10.21) and hematological cancers (SIR 6.97, 95% CI 1.77-18.98).

CONCLUSION

Although showing a causal association necessitates further investigation, our results support the idea that periodontitis might be associated with increased cancer risk, particularly with hematological, breast and prostate cancers.

[Research progress on the relationship between triggering receptor expressed on myeloid cells 1 and 2 and malignant tumors]

Increasing scientific evidence supports the positive relationship between inflammation and cancer development. The immune response initiated by pattern recognition receptors is critical to triggering of tumor-associated inflammation. Triggering receptor expressed on myeloid cells (TREM) is an immunoglobulin of the super transmembrane glycoprotein family, which is mainly expressed on select groups of myeloid cells. The most important members of TREM comprise TREM-1 and TREM-2. Activation of TREM-1 and TREM-2 signaling is initiated upon binding of their ligands. Subsequently, cross-linking reactions of downstream effectors occur, resulting in inflammation regulation. Recently, the connection between TREM and malignant tumors has been widely noticed and studied. This review summarizes studies of association between TREM-1, TREM-2, and malignant tumors in the medical field to provide new ideas for study on the correlation between periodontitis and oral cavity cancer.

Bacterial protease uses distinct thermodynamic signatures for substrate recognition

Porphyromonas gingivalis and Porphyromonas endodontalis are important bacteria related to periodontitis, the most common chronic inflammatory disease in humans worldwide. Its comorbidity with systemic diseases, such as type 2 diabetes, oral cancers and cardiovascular diseases, continues to generate considerable interest. Surprisingly, these two microorganisms do not ferment carbohydrates; rather they use proteinaceous substrates as carbon and energy sources. However, the underlying biochemical mechanisms of their energy metabolism remain unknown. Here, we show that dipeptidyl peptidase 11 (DPP11), a central metabolic enzyme in these bacteria, undergoes a conformational change upon peptide binding to distinguish substrates from end products. It binds substrates through an entropy-driven process and end products in an enthalpy-driven fashion. We show that increase in protein conformational entropy is the main-driving force for substrate binding via the unfolding of specific regions of the enzyme (“entropy reservoirs”). The relationship between our structural and thermodynamics data yields a distinct model for protein-protein interactions where protein conformational entropy modulates the binding free-energy. Further, our findings provide a framework for the structure-based design of specific DPP11 inhibitors.

Elevated Levels of Urinary PGE-M Are Found in Tobacco Users and Indicate a Poor Prognosis for Oral Squamous Cell Carcinoma Patients

Cyclooxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2) plays a role in the development and progression of epithelial malignancies. Measurements of urinary PGE-M, a stable metabolite of PGE2, reflect systemic PGE2 levels. Here, we investigated whether urinary PGE-M levels were elevated in healthy tobacco users and in patients with oral squamous cell carcinoma (OSCC). Median urinary PGE-M levels were increased in healthy tobacco quid chewers [21.3 ng/mg creatinine (Cr); n = 33; P = 0.03] and smokers (32.1 ng/mg Cr; n = 31; P < 0.001) compared with never tobacco quid chewers-never smokers (18.8 ng/mg Cr; n = 30). Urinary PGE-M levels were also compared in OSCC patients versus healthy tobacco users. An approximately 1-fold increase in median urinary PGE-M level was found in OSCC patients (48.7 ng/mg Cr, n = 78) versus healthy controls (24.5 ng/mg Cr, n = 64; P < 0.001). We further determined whether baseline urinary PGE-M levels were prognostic in OSCC patients who underwent treatment with curative intent. A nearly 1-fold increase in baseline urinary PGE-M levels (64.7 vs. 33.8 ng/mg Cr, P < 0.001) was found in the group of OSCC patients who progressed (n = 37) compared with the group that remained progression free (n = 41). Patients with high baseline levels of urinary PGE-M had both worse disease-specific survival [HR, 1.01 per unit increase; 95% confidence interval (CI), 1.01-1.02; P < 0.001] and overall survival (HR, 1.01 per unit increase; 95% CI, 1.00-1.02; P = 0.03). Taken together, our findings raise the possibility that NSAIDs, prototypic inhibitors of PGE2 synthesis, may be beneficial for reducing the risk of tobacco-related aerodigestive malignancies or treating OSCC patients with high urinary PGE-M levels. Cancer Prev Res; 9(6); 428-36. ©2016 AACR.