Denture induced mechanotransduction can contribute to oral carcinogenesis

Unveiling denture-induced oral lesions: A comprehensive study on classification and pain assessment

BACKGROUND

Denture-induced oral Lesions (DIOLs) often manifests shortly after the placement or adjustment of new or realigned dentures, frequently resulting in severe pain and discomfort.

OBJECTIVES

This study aimed to classify DIOLs placing a particular emphasis on assessing the associated pain.

METHODS

A prospective case study was conducted involving 126 patients who were fitted with a total of 193 dentures of various types at the Hadassah School of Dental Medicine. All patients underwent comprehensive intra-oral examinations within 1-8 weeks following denture delivery, completed symptom questionnaires and had their medical records reviewed. Key variables documented included age, gender, overall health status, denture type, and a detailed description of the DIOLs. The description encompassed factors such as lesion location, shape, colour, size, border characteristics, ulcerative appearance, membrane coverage, 3D morphology (elevated, immersed and flat) and patient-reported Verbal Pain Score (VPS) when touching the DIOLs, when wearing the denture, and when not wearing the denture.

RESULTS

Notably, 25.4% of denture wearers required no adjustments, while 14.4% necessitated more than three revisions. A majority (71.8%) of DIOLs cases were associated with mandibular complete dentures, primarily situated on the alveolar ridge. The mean VPS indicated a pain intensity of 7 ± 2.1, with temporary dentures in both jaws causing the most discomfort. Implant-supported overdentures were particularly painful when placed in the mandible. Additionally, VPS scores were higher among older individuals and those with prior prosthetic experiences. A significant correlation was observed between pain intensity and presence of chronic health condition (0.036).

CONCLUSIONS

This study revealed distinct characteristics of DIOLs and highlighted the multifactorial nature of pain experienced following the development of DIOLs. Insights into the influence of patient and denture characteristics on DIOLs and pain intensity can guide healthcare professionals in optimising patient comfort and satisfaction.

Matrix stiffness induces an invasive-dormant subpopulation via cGAS-STING axis in oral cancer

OBJECTIVES

Dormancy is a crucial machinery for cancer cells to survive hostile microenvironment. It is considered as the major cause of post-treatment relapse and metastases. However, its regulatory mechanism in oral squamous cell carcinoma (OSCC) remains unclear. Here we sought to decipher the impacts of matrix stiffness on OSCC-cell dormancy.

MATERIALS AND METHODS

Clinicopathological relevance of matrix stiffness in OSCC was analyzed in a 127 patients' cohort. Impacts of stiffness-related mechanical stress (MS) on OSCC-cell behaviors were investigated in vitro and in vivo. Transcriptomic profiling of MS induced dormant cells were performed, following by mechanistic investigations on MS-induced dormancy. The functional relevance of cGAS in OSCC were analyzed through a bioinformatic approach.

RESULTS

Stiffened matrix correlated with poor survival and post-surgical recurrence in OSCC. Stiffness-related MS induces a dormant subpopulation in OSCC cells, which showed increased drug resistance, enhanced tumor repopulating ability, and an unexpected upregulation of epithelial-mesenchymal transition (EMT) and invasiveness. Mechanistically, MS caused DNA damage, resulted in activation of cGAS-STING signaling. Either blocking of cGAS or STING dramatically impeded the MS-induced production of this invasive-dormant subpopulation. Moreover, cGAS was found being central to the cell-cycle regulation and correlated with poor prognosis in OSCC.

DISCUSSION

We revealed a previously unsuspected role of cGAS-STING axis in mediating the induction of an invasive-dormant subpopulation in response to mechanical cues. Our findings indicated an adaptive machinery whereby tumor cells survive and escape from harsh microenvironment. Targeting this machinery may be a potential strategy for preventing post-therapeutic recurrence and lymphatic metastasis in OSCC.

Modifiable risk factors for oral cavity cancer in non-smokers: A systematic review and meta-analysis

BACKGROUND

Oral cavity cancer (OCC) is traditionally associated with smoking, but there is an increasing prevalence of the disease among non-smokers. This review investigates possible modifiable risk factors in the development of OCC in non-smokers (OCCNS).

METHODS

PubMed, EMBASE, Web of Science, and Scopus were searched for publications prior to June 2021. Comparative studies investigating modifiable OCCNS risk factors were identified following PRISMA guidelines. Publication date, population size, and results were indexed. Study quality was assessed using MINORS (Methodological Index for Non-Randomized Studies). Factors examined by multiple studies were analyzed using random-effect meta-analysis framework.

RESULTS

Literature search resulted in 1,625 unique publications. 52 records met inclusion criterion, investigating alcohol (n = 22), chewing products (n = 18), diet (n = 7), dental health (n = 11), and medical comorbidities (n = 6).

CONCLUSION

This review demonstrates the paucity of large studies investigating OCCNS risk factors. Further investigation is warranted to help clinicians risk-stratify patients without traditional risk factors.

Evolution of the Incidence of Oral Cavity Cancers in the Elderly from 1990 to 2018

OBJECTIVES

To describe the evolution of the incidence of oral cavity cancers (OCC) among elderly patients in France between 1990 and 2018 and to compare it to the incidence of other cancers sharing the same main risk factors.

MATERIAL AND METHODS

The incidence of cancers in mainland France from 1990 to 2018 was estimated from incidence data observed in every cancer registry of the Francim network. Incidence was modeled by a 2-dimensional penalized spline of age and year of diagnosis, associated with a random effect corresponding to the registry. The elderly population was divided into two groups: 70-79 years old and ≥80 years old.

RESULTS

There was a 72% increase in the number of OCC cases in women over 70 years of age between the periods 1990-1999 and 2010-2018. As for men, there was a stabilization in the number of cases (+2%). Over the same period, for laryngeal and hypopharyngeal cancers, there was a decrease in incidence in elderly men and an increase in elderly women, although less marked than for OCC.

CONCLUSIONS

Since the 1990s, the incidence of OCC has been increasing in elderly subjects in France, particularly in women. Population aging and growth or alcohol and tobacco consumption alone do not seem to explain this increase, which is not observed in the same proportions for other upper aerodigestive tract cancer subsites sharing the same main risk factors.

The Hippo pathway: a renewed insight in the craniofacial diseases and hard tissue remodeling

The Hippo pathway plays an important role in many pathophysiological processes, including cell proliferation and differentiation, cell death, cell migration and invasion. Because of its extensive functions, Hippo pathway is closely related to not only growth and development, but also many diseases, including inflammation and cancer. In this study, the role of Hippo pathway in craniofacial diseases and hard tissue remodeling was reviewed, in attempting to find new research directions.

Hemorrhagic areas as a histological prognosticator in oral cancer: A novel proposition

Determination of prognosis in oncology practice is a major challenge and many histological prognosticators have been applied because of the ease and simplicity of using them in day-to-day practice. Our histopathologic observation on 96 oral squamous cell carcinoma (OSCC) specimens revealed 34 cases associated with frank hemorrhagic areas, which were close to tumor cells. Hence, we propose that there could be a cross-talk between tumor cells and RBCs which can modulate the biological behavior of the tumor and prognosis of the patient. In the present paper, a scientific foundation is provided for this proposition. Furthermore, an experimental approach is recommended which will facilitate the identification of extracellular metabolites within the tumor microenvironment near RBCs. Such studies may pave the way for a better understanding of the clinical heterogeneity of oral cancer due to differential heme content of red blood cells (RBCs) in the tumor microenvironment (TME).