Interventions for treating oral leukoplakia to prevent oral cancer

In situ treatment with a TLR9 agonist virus-like particle to promote immune responses against oral epithelial dysplasia progression

Leukoplakia, a common type of oral dysplasia, is simply defined as a white patch in the mouth or other mucosal surface. Oral dysplasia is the most common premalignancy in the oral cavity and yet it is insufficiently researched and thus both diagnosing and treating oral dysplasia are still problematic issues. This study focuses on the immune signature of oral dysplasia and explores whether stimulating the immune system with an immune therapy, vidutolimod (± immune checkpoint blockade (ICB)), can prevent the progression of oral dysplasia or even cause regression. Vidutolimod, a virus-like particle encapsulating G10, is believed to activate plasmacytoid dendritic cells (pDCs) through the activation of the Toll-like receptor 9 (TLR9). To investigate this, an established murine model for inducing oral cancer was used to study oral dysplasia development and response to in situ injection of vidutolimod at the premalignant phase. The effect of treatment was analyzed histologically and immunologically. ELISA revealed significantly elevated levels of IFN-γ, IL-12, and TNF-α in the sera of mice after 24 h of one treatment with vidutolimod + ICB as well as increased levels of proliferating T cells and pDCs in draining lymph nodes 72 h after the third and final treatment, thus indicating the immune-boosting effect of this therapy. Vidutolimod + ICB caused a significant decrease in Ki-67 expression by epithelial cells in the lesion area compared to untreated mice, implicating that this treatment regime may prevent lesion progression.

Probiotics and prebiotics: new treatment strategies for oral potentially malignant disorders and gastrointestinal precancerous lesions

Oral potentially malignant disorders (OPMDs) and gastrointestinal precancerous lesions (GPLs) are major public health concerns because of their potential to progress to cancer. Probiotics, prebiotics, and engineered probiotics can positively influence the prevention and management of OPMDs and GPLs. This review aims to comprehensively review the application status of probiotics, prebiotics and engineered probiotics in OPMDs and GPLs, explore their potential mechanisms of action, and anticipate their future clinical use.

Surgical treatment compared with "wait and see" in patients affected by oral leukoplakia to prevent oral cancer: Preliminary data from a multicenter randomized controlled trial

OBJECTIVE

Oral leukoplakia (OL) is one of the most common and investigated oral potentially malignant disorders (OPMD). Preventing OSCC occurrence should be the primary outcome in the clinical management of OL. Surgical removal of OL is performed by most clinicians, although its effectiveness in reducing OSCC onset has still not been established by randomized controlled trials (RCT). Wait and see approach is characterized by frequent clinical examinations and periodical biopsies of OL, avoiding unnecessary surgical procedures. This is the first multicenter RCT in literature aiming at comparing the effectiveness of surgical removal and the "wait and see" approach in preventing OSCC onset in patients affected by dysplastic and non-dysplastic OL.

METHODS

Two Italian referral care centres for oral diseases were involved in this multicenter two-arm RCT comparing the surgical removal of OL (group A) and the "wait and see" approach (group B), with the aim of reducing oral cancer onset.

RESULTS

This report shows preliminary data on the first 161 patients, with a mean follow-up of 19.14 ± 11.25 months. Eight cases of OSCC occurred (6 out 8 involving the tongue): one case in group A and seven cases in group B. Moreover, OL recurred in 13 (20%) cases after surgical excision.

CONCLUSIONS

Within the limitations of this preliminary report, these initial data underline the increased risk of OSCC onset in the case of OL of the tongue in the presence of epithelial dysplasia in group B ("wait and see") compared to group A (surgery). This RCT is currently ongoing at the same clinical departments, with the aim of enrolling 310 patients and collecting data at 5-year follow-up, in order to achieve conclusive results, in an evidence-based medicine approach.

Hypovitaminosis D in patients with oral leukoplakia: insights from a cross-sectional study

Introduction

Oral leukoplakia is one of the most frequent oral potentially malignant disorders. The present study aims to compare serum vitamin D levels between patients with and without oral leukoplakia, by smoking habit.

Methods

This cross-sectional study involved a group of 45 cases with oral leukoplakia and a control group with 45 individuals. In both groups a pathology report was done, and for leukoplakia a binary classification of low- and high-grade epithelial dysplasia was employed. Serum 25(OH)D3 vitamin D levels, and data on smoking status, age, gender, comorbidities, and clinical and pathological characteristics were collected for both groups.

Results

vitamin D levels were lower in the oral leukoplakia group with a median of 19.1 ng/ml, while the control group had a median of 24.8 ng/ml. When subdividing each group by smoking habit, the smoking case group had a median of 19.4 ng/ml (IQR: 15.7-21.5 ng/ml), the non-smoking case group had 18.8 ng/ml (IQR: 13.6-29.2 ng/ml), the smoking control group had 21.8 ng/ml (IQR: 17.5-27.3 ng/ml), and the non-smoking control group had 25.4 ng/ml (IQR: 20.4-32.9 ng/ml) (p<0.05). When comparing serum vitamin D levels, statistically significant differences were found between the smoking case group versus the non-smoking control group and between the non-smoking case group versus the non-smoking control group (p<0.05). Serum vitamin D levels by histopathological diagnosis showed no differences between leukoplakia groups.

Discussion

This study shows that serum vitamin D levels were lower in patients with OL compared to those without OL, which was more evident in the smoking group. Patients with OL were previously observed to have hypovitaminosis D, without assessing smoking habits. This finding suggests a possible role of vitamin D deficiency in the development of OL, which could be more marked in smokers. This opens the possibility of future research on vitamin D as a chemopreventive agent in the malignant transformation of OL, and to evaluate the relationship between smoking and hypovitaminosis D.

Imiquimod for the treatment of oral leukoplakia: A two-center retrospective study

OBJECTIVES

We aimed to assess the effectiveness of the use of topical imiquimod for the management of oral leukoplakia (OL).

METHODS

This was a retrospective study. Medical chart reviews were conducted to identify patients with biopsy-proven OL treated with topical 5% imiquimod. Data included OL characteristics, histopathological diagnosis, treatment outcome, and adverse events (AEs). Treatment response was assessed by measuring the percentage reduction in the size of OL lesions.

RESULTS

33 patients (51.5% females; median age: 65 years) with 38 lesions were included. OLs were either localized (23.7%) or multifocal lesions (76.3%), with the majority on the gingiva (86.8%). Pretreatment histopathological diagnoses were dysplasia in 84.2% and nonreactive hyperkeratosis in 15.8%. Most regimens consisted of 60-minute applications, 5-days-a-week, for 6 weeks. At the end of treatment, 81.6% of 38 lesions showed a reduction in size with 68.4% exhibiting ≥50% reduction in size, and 42.1% exhibiting complete resolution. Application site reactions were the most common with pain/soreness/sensitivity occurring in 86.8%. Fatigue was the most frequently reported systemic AE (28.9%).

CONCLUSION

Two-thirds of OL lesions had ≥50% reduction in size. Most AEs were temporary and resolved upon treatment discontinuation. Prospective studies are needed to further assess Imiquimod's effectiveness in OL management.

Case report: Non-invasive cyto-salivary sampling and biomarker detection via ELISA versus histopathology for diagnosing oral potentially malignant disorders - Insights from a case-control study

Oral leukoplakia is classified among oral potentially malignant disorders (OPMDs) by the World Health Organization (WHO). The visual oral examination (VOE) is the most used method for identifying lesions in their early stages. Given that the diagnosis of oral cancer is often late, there is an urgent need for early detection and examination of oral lesions. Surgical biopsy represents the gold standard as a diagnostic method, but because it is invasive, it cannot be repeated for periodic checks. We report the case of a lesion on the buccal mucosa of a 65-year-old male patient with a malignant appearance. The patient underwent a novel non-invasive cyto-salivary sampling and ELISA immunoassay for tumor biomarker detection and biopsy with histopathological analysis. The rapid ELISA test results excluded signs of malignancy, providing valuable insights into the lesion's immunophenotypic profile, which were consistent with the histopathological examination findings. This case report highlights the clinical and histopathological characteristics of a lesion with the aspect of Proliferative Verrucous Leukoplakia (PVL), emphasizing its challenging diagnosis and management. The integration of non-invasive cytobrush sampling with biomarker analysis proved valuable in detecting specific tumor biomarkers, potentially indicating ongoing tumor transformation. Monitoring these markers over time could enhance early detection and management strategies, thereby improving patient outcomes. This approach underscores the utility of non-invasive techniques in phenotyping oral lesions and supporting clinical decision-making in oral medicine.

FGF6 inhibits oral squamous cell carcinoma progression by regulating PI3K/AKT and MAPK pathways

To explore diagnostic and prognostic biomarkers in the progression of oral squamous cell carcinoma (OSCC) and to reveal their regulatory mechanisms in key pathways. A RayBiotech protein chip was used to screen differentially expressed serum proteins in OSCC, oral leukoplakia (OLK), and healthy participants. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were used to determine the pathways enriched by characteristic differential proteins. Immunohistochemical analysis and western blotting were used to verify the expression of characteristic differential proteins and key regulatory factors in human tissues and in a nude mouse model. Fibroblast growth factor 6 (FGF6) was identified as a key differential protein and was weakly expressed in OSCC tissues. The mitogen-activated protein kinases (MAPK) and PI3K-AKT pathways were identified as key signaling pathways. The results showed that pERK, Cyclin D1, pAKT, and BCL2 were highly expressed in OSCC, Caspase9 was lowly expressed in OSCC. With an increase in FGF6 expression in nude mice, the expression of FGFR4, pERK, Cyclin D1, pAKT, BCL2, GPX4, and ACSL4 increased, and the expression of Caspase9 decreased. FGF6 may change the expression of apoptosis-related proteins and proliferation factors by binding to FGFR4 in the PI3K-AKT/MAPK pathway and may inhibit the ferroptosis of OSCC, thereby possibly participating in the process of inhibiting OSCC.

Comprehensive analysis of clinical research profiles and study characteristics of oral potentially malignant disorders: an observational study

Objective

The study aims to present an observational study of clinical trials on Oral Potentially Malignant Disorders (OPMDs) and corresponding publications.

Study design and setting

We searched the OPMDs-related clinical studies registered in the ClinicalTrials.gov database before March 1, 2024. Subsequently, we investigated the publication status of primary completed studies using PubMed and Google Scholar.

Results

A total of 185 studies were identified for analysis, including 141 interventional studies and 44 observational studies. The most commonly studied disease type was oral lichen planus (OLP), accounting for 113 studies (61.1 %). Interventional studies on OPMDs were predominantly early-phased, blind, randomized, parallel and single-center. The primary purpose of these studies was treatment (106, 75.2 %). Among the treatments, herbal medicine (21, 19.8 %), photodynamic therapy (17, 16.0 %), and glucocorticoids (14, 13.2 %) were of greatest interest. In addition, 58 (63.0 %) of the primarily completed interventional studies were published, with a median time to publication of 33.6 months. Published interventional studies including OLP patients and factorial designs had shorter time to publication. However, these studies were less frequently published in high-impact journals and most primary results were positive.

Conclusions

Clinical trials on OPMDs predominantly focused on OLP and herbal medicine. The quality of studies is unsatisfactory and publication rate is suboptimal. Improvements are needed in ClinicalTrials.gov registration standards, high-quality study design and more stringent publishing requirements.

Effectiveness of Fenugreek as an Adjuvant in the Management of Oral Potentially Malignant Disorders: A Randomized Controlled Trial

AIM

This study aimed to evaluate the effectiveness of fenugreek as an adjuvant in managing oral potentially malignant disorders (OPMDs), specifically leukoplakia, lichen planus, and oral submucous fibrosis (OSMF).

MATERIALS AND METHODS

Twenty-one participants prediagnosed with OPMDs were randomly divided into a study group (SG) and a control group (CG), with 10 participants in SG and 11 in CG, respectively. The SG received 2 gm of fenugreek as an adjuvant with standard systemic treatments tailored to the respective lesions: intralesional injection of vitamin A 1,00,000 IU (Aquasol A) and topical application of triamcinolone acetonide 0.1% (Kenacort) for 2 months for leukoplakia. Subjects with oral lichen planus were administered prednisolone 5 mg/day (Wysolone), chlorhexidine mouthwash 0.2% (Peridex), and Zincovit once daily for 8 weeks. For subjects with OSMF, one capsule of SM Fibro once daily for 12 weeks along with dexamethasone 1.5 mL (Decadron) was given, and hyaluronidase 1,500 IU (Hynidase) with 0.5 mL lignocaine HCL (Xylocaine) was injected intralesionally biweekly and mouth exercise was advised for 2 months; control group received only the standard treatment. Sociodemographic data were collected, and clinical assessments, evaluating size and shape for leukoplakia, erythema, and burning sensation for oral lichen planus, and mouth opening, cheek flexibility, and burning sensation for OSMF were assessed from baseline through 2 months. Data collected were organized in Excel and analyzed using Statistical Package for the Social Sciences version 21.0.

RESULTS

The SG and CG had 10 and 11 participants, with 4 in each group for leukoplakia, 2 participants in SG and 3 in CG for lichen planus, and 4 participants for OSMF in each group, respectively. Most participants presented with leukoplakia under 2 cm on the buccal mucosa bilaterally, with no significant changes in size or shape postintervention. For lichen planus, mild erythema and burning sensation were noted, but there were no significant differences within or between groups postintervention. A mild burning sensation, a statistically significant improvement in mouth opening was observed in SG (p < 0.051) when compared with CG after 8 weeks postintervention in OSMF. Also, significant improvement in cheek flexibility was noted from baseline to the fourth follow-up in SG post intervention. However, there were no differences between groups during the follow-up period.

CONCLUSION

The findings from this trial suggest that SG showed significant improvement in OSMF than CG, whereas the improvements in leukoplakia and lichen planus remained same in both groups.

CLINICAL SIGNIFICANCE

Fenugreek, being a cost-effective and affordable agent known for its anticancer, anti-inflammatory, antioxidant, and antiulcerative properties, could be used as an adjuvant for its management in OPMDs. How to cite this article: Balasundaram N, Narayanan MBA, Arul Antony LS, et al. Effectiveness of Fenugreek as an Adjuvant in the Management of Oral Potentially Malignant Disorders: A Randomized Controlled Trial. J Contemp Dent Pract 2024;25(10):921-929.

Effect of the gut microbiome and inflammation-related proteins on oral leukoplakia: a Mendelian randomization study and mediation analysis

Background

Oral leukoplakia (OL) is the most common potentially malignant disease of the oral cavity. In recent years, studies have identified a correlation between the gut microbiota (GM) and oral cancer, in addition, inflammation-related proteins have been reported to play an important role in the development of OL. However, the causal relationship between gut microbiota and OL, as well as whether cytokines play a mediating role, remain unclear.

Methods

In this Mendelian randomization (MR) study, the genome-wide association studies (GWAS) (n=18340) of the MiBioGen consortium microbiome was used as exposure data. Genetic variation data related to OL were extracted from the Finngen R9 project (513 cases of OL and 411668 controls). The 91 inflammation-related proteins obtained in the literature serve as potential mediators. Two-sample Mendelian randomization analysis was applied to infer causality using Inverse Variance Weighted (IVW), MR Egger, weighted media, simple mode and weighted mode method. Subsequently, sensitivity analysis was conducted to ensure the robustness of the MR results. In addition, we conducted reverse MR analysis to alleviate reverse causality. Finally, we used mediation analysis to determine the pathway mediated by inflammation-related proteins from the gut microbiota to OL.

Results

The five bacterial taxa in the gut microbiota indicate a potential causal relationship with the development of OL. Notably, family Clostridiaceae1 was negatively correlated with the risk of OL development, while genus Dorea, genus Ruminococcus1, genus Senegalimasilia and genus Veillonella were positively associated with the risk of OL development. In addition, this study identified a potential causal relationship between interleukin-10 receptor subunit alpha (IL-10RA), interleukin-18 receptor 1(IL18-R1) and the occurrence of OL. In addition, intermediary analysis indicates that IL18-R1 mediated the pathway between the gut microbiota genus Senegalimasilia and OL.

Conclusions

In summary, our research emphasize the complex relationship between gut microbiota, inflammation-related proteins and OL. The identified associations and mediating effects provide new insights into potential therapeutic approaches for targeting the gut microbiota in the management of OL, and contribute to its prevention, diagnosis and treatment.

The potential of retinoic acid receptors as prognostic biomarkers and therapeutic targets in gastric cancer

Background

Gastric cancer is a heterogeneous collection of tumors characterized by low survival rates. All-trans retinoic acid (retinoic-acid) is a clinically useful therapeutic agent belonging to the chemical family of retinoids, which consists of both natural and synthetic derivatives of vitamin-A. Retinoids are essential components of the normal diet and they regulate different physiological processes. From a therapeutic point of view, retinoic-acid is the first example of clinically useful differentiating agent. Indeed, the differentiating properties of this compound have promoted the use of retinoic-acid as a standard of care in Acute-Promyelocytic-Leukemia, a rare form of acute myeloid leukemia. In this study, we determine the RNA expression of the six isoforms of Retinoic-Acid-Receptors (RARα/RARβ/RARγ/RXRα/RXRβ/RXRγ) in view of their potential use as gastric cancer progression markers and/or therapeutic targets. In addition, we evaluate associations between the expression of these receptors and a simplified molecular classification of stomach tumors as well as the clinical characteristics of the cohort of patients analyzed. Finally, we define the prognostic value of the various Retinoic-Acid-Receptors in gastric cancer.

Methods

In this single institution and retrospective RAR-GASTRIC study, we consider 55 consecutive gastric cancer patients. We extract total RNA from the pathological specimens and we perform a NanoString Assay using a customized panel of genes. This allows us to determine the expression levels of the RAR and RXR mRNAs as well as other transcripts of interest.

Results

Our data demonstrate ubiquitous expression of the RAR and RXR mRNAs in gastric cancers. High levels of RARα, RARβ, RXRα and RXRβ show a significant association with stage IV tumors, "de novo" metastatic disease, microsatellite-stable-status, epithelial-to-mesenchymal-transition, as well as PIK3CA and TP53 expression. Finally, we observe a worse overall-survival in gastric cancer patients characterized by high RARα/RARβ/RARγ/RXRβ mRNA levels.

Conclusions

In gastric cancer, high expression levels of RARα/RARβ/RARγ/RXRβ transcripts are associated with poor clinical and molecular characteristics as well as with reduced overall-survival. Our data are consistent with the idea that RARα, RARβ, RARγ and RXRβ represent potential prognostic markers and therapeutic targets of gastric cancer.

Comprehensive insights into oral squamous cell carcinoma: Diagnosis, pathogenesis, and therapeutic advances

Oral squamous cell carcinoma (OSCC) is considered the most common type of head and neck squamous cell carcinoma (HNSCC) as it holds 90 % of HNSCC cases that arise from multiple locations in the oral cavity. The last three decades witnessed little progress in the diagnosis and treatment of OSCC the aggressive tumor. However, in-depth knowledge about OSCC's pathogenesis, staging & grading, hallmarks, and causative factors is a prime requirement in advanced diagnosis and treatment for OSCC patients. Therefore present review was intended to comprehend the OSCCs' prevalence, staging & grading, molecular pathogenesis including premalignant stages, various hallmarks, etiology, diagnostic methods, treatment (including FDA-approved drugs with the mechanism of action and side effects), and theranostic agents. The current review updates that for a better understanding of OSCC progress tumor-promoting inflammation, sustained proliferative signaling, and growth-suppressive signals/apoptosis capacity evasion are the three most important hallmarks to be considered. This review suggests that among all the etiology factors the consumption of tobacco is the major contributor to the high incidence rate of OSCC. In OSCC diagnosis biopsy is considered the gold standard, however, toluidine blue staining is the easiest and non-invasive method with high accuracy. Although there are various therapeutic agents available for cancer treatment, however, a few only are approved by the FDA specifically for OSCC treatment. The present review recommends that among all available OSCC treatments, the antibody-based CAR-NK is a promising therapeutic approach for future cancer treatment. Presently review also suggests that theranostics have boosted the advancement of cancer diagnosis and treatment, however, additional work is required to refine the role of theranostics in combination with different modalities in cancer treatment.

The mechanism of low molecular weight fucoidan-incorporated nanofiber scaffolds inhibiting oral leukoplakia via SR-A/Wnt signal axis

Oral leukoplakia (OLK) is the most common oral precancerous lesion, and 3%-17% of OLK patients progress to oral squamous cell carcinoma. OLK is susceptible to recurrence and has no effective treatment. However, conventional drugs have significant side effects and limitations. Therefore, it is important to identify drugs that target OLK. In this study, scavenger receptor A (SR-A) was found to be abnormally highly expressed in the oral mucosal epithelial cells of OLK patients, whereas molecular biology studies revealed that low molecular weight fucoidan (LMWF) promoted apoptosis of dysplastic oral keratinocytes (DOK) and inhibited the growth and migration of DOK, and the inhibitory effect of LMWF on OLK was achieved by regulating the SR-A/Wnt signaling axis and related genes. Based on the above results and the special situation of the oral environment, we constructed LMWF/poly(caprolactone-co-lactide) nanofiber membranes with different structures for the in-situ treatment of OLK using electrospinning technology. The results showed that the nanofiber membranes with a shell-core structure had the best physicochemical properties, biocompatibility, and therapeutic effect, which optimized the LMWF drug delivery and ensured the effective concentration of the drug at the target point, thus achieving precise treatment of local lesions in the oral cavity. This has potential application value in inhibiting the development of OLK.

The value of regular follow-up of oral leukoplakia for early detection of malignant transformation

OBJECTIVES

Evaluate whether regular follow-up of oral leukoplakia (OL) resulted in early detection of malignant transformation (MT).

METHOD

Two hundred and twenty-two consecutive patients with OL (147 females, 75 males); median follow-up period of 64 months (range: 12-300). Three groups were distinguished: group A (n = 92) follow-up at the hospital; group B (n = 84) follow-up by their dentist; group C (n = 46) lost to follow-up.

RESULTS

OLs in group B compared to group A, were smaller in size (<2 cm; p < 0.001), showed more hyperkeratosis (p < 0.001) and less moderate/severe dysplasia (p < 0.001). MT occurred in 45 (20%) patients: 32 (35%) in group A, five (6%) in group B and eight (17%) in group C. There was no significant difference in clinical tumour size between group A (median: 15 mm, range: 1-40) and group B (median: 10 mm, range: 3-25; p = 0.496). Tumour size was smaller for patients in groups A and B (median: 10 mm, range 1-40) compared to group C (median: 33 mm, range: 3-100; p = 0.003). There was a positive correlation between tumour size and interval between the last visit in all patients (p = 0.022).

CONCLUSION

Regular follow-up of OL resulted in early detection of MT. If properly selected, follow-up of OL performed by the dentist seems feasible.

Genomic Engineering of Oral Keratinocytes to Establish In Vitro Oral Potentially Malignant Disease Models as a Platform for Treatment Investigation

Precancerous cells in the oral cavity may appear as oral potentially malignant disorders, but they may also present as dysplasia without visual manifestation in tumor-adjacent tissue. As it is currently not possible to prevent the malignant transformation of these oral precancers, new treatments are urgently awaited. Here, we generated precancer culture models using a previously established method for the generation of oral keratinocyte cultures and incorporated CRISPR/Cas9 editing. The generated cell lines were used to investigate the efficacy of a set of small molecule inhibitors. Tumor-adjacent mucosa and oral leukoplakia biopsies were cultured and genetically characterized. Mutations were introduced in CDKN2A and TP53 using CRISPR/Cas9 and combined with the ectopic activation of telomerase to generate cell lines with prolonged proliferation. The method was tested in normal oral keratinocytes and tumor-adjacent biopsies and subsequently applied to a large set of oral leukoplakia biopsies. Finally, a subset of the immortalized cell lines was used to assess the efficacy of a set of small molecule inhibitors. Culturing and genomic engineering was highly efficient for normal and tumor-adjacent oral keratinocytes, but success rates in oral leukoplakia were remarkably low. Knock-out of CDKN2A in combination with either the activation of telomerase or knock-out of TP53 seemed a prerequisite for immortalization. Prolonged culturing was accompanied by additional genetic aberrations in these cultures. The generated cell lines were more sensitive than normal keratinocytes to small molecule inhibitors of previously identified targets. In conclusion, while very effective for normal keratinocytes and tumor-adjacent biopsies, the success rate of oral leukoplakia cell culturing methods was very low. Genomic engineering enabled the prolonged culturing of OL-derived keratinocytes but was associated with acquired genetic changes. Further studies are required to assess to what extent the immortalized cultures faithfully represent characteristics of the cells in vivo.

Clinical efficacy of photodynamic therapy of oral potentially malignant disorder

OBJECTIVE

To investigate the clinical efficacy of aminovalerate hydrochloride photodynamic therapy (PDT) for oral potentially malignant disorder (OPMD),oral leukoplakia (OLK), along with identifying the influencing factors.Additionally, the study aims to detect the rates of recurrence and malignancy after PDT.

METHOD

60 patients with OPMD who received PDT at our hospital from 2006 to 2021 were included in this study. Relevant patient medical data were collected and analyzed using SAS 9.4 software.The Mann-Whitney U test was used to retrospectively analyze the factors influencing clinical efficacy, as well as recurrence rate and malignant transformation rate (MTR) after treatment.

RESULT

Among the 60 OPMD patients receiving PDT, complete remission in 13 (21.67 %), partial remission in 39 (65.00 %), and no remission in eight (13.33 %), resulting in an overall effective rate of 86.67 %.Fifteen patients experienced relapse, leading to a recurrence rate of 25.00 %. Among these relapses,11 patients occurred within one year after treatment, corresponding to an 18.33 % recurrence rate during that period. Moreover, nine patients developed malignant transformation (MT), resulting in an MTR of 15.00 %. Out of these patients, six individuals developed MT within one year after treatment, resulting in a one-year MTR of 10.00 %.

CONCLUSION

The study findings indicate that PDT shows promising clinical efficacy in the treatment of OPMD, with relatively limited and tolerable postoperative adverse reactions. However, there remains a certain rate of recurrence and malignancy after treatment. Therefore, close attention should be paid to postoperative monitoring, regular follow-up, and further expansion of the sample size to observe its long-term efficacy.

A Comparative Study of the Treatment of Oral Premalignant Lesions with Surgical Excision and Medical Therapy

Introduction

Potentially malignant oral epithelial lesions are a group of oral conditions with an altered morphological state of the normal mucosal lining and include different lesions such as leukoplakia, erythroplakia, submucosal fibrosis, and lichen planus.

Aim

To compare the outcome of premalignant oral lesions after medical therapy consisting of submucosal intralesional injection of triamcinolone with hyaluronidase and surgical excision.

Materials and Methods

This was a comparative prospective interventional study and the study was conducted among 50 patients presented to the Department of Otorhinolaryngology with premalignant oral lesions from the year 2020 to 2022. Patients were divided into two groups by random allocation, group A was treated with medical therapy, and Group B was treated with surgical excision and followed for a minimum of 6 months and the outcome has been categorized.

Results

All patients were divided into two groups-group A and group B, group A consisted of 22 (44%) patients who were given medical therapy, and group B consisted of 28 (56%) patients who underwent surgical excision. In group A, the clinical response was seen in 8 (36.36%) and in group B, the clinical response was seen in 18 (64.29%) patients.

Conclusion

Surgical excision was found to be better with more cases of clinical response (64.29%) when compared to medical treatment (36.36%) with a p value of 0.0497 which is significant whereas malignant transformation was almost equal in medical therapy and surgical treatment which was 13.64% and 14.28%, respectively.

Oral Potentially Malignant Disorders and Oral Cancer in Saudi Arabia: An Epidemiological Review of the Literature

Background: Oral potentially malignant disorders (OPMDs) are a group of chronic oral mucosal diseases associated with an increased risk of malignant transformation. Multiple studies have investigated the prevalence of these conditions in multiple regions; however, there are limited data about the prevalence of OPMDs in the Kingdom of Saudi Arabia (KSA). This paper aims to review the prevalence of OPMDs in the KSA, to ensure better understanding of the population risk and propose a more standardised approach to the diagnosis and management of this group across the KSA. In addition, this review will discuss the prevalence of oral cancer in the KSA, considering independent risk factors for oral cancer development. Methods: Electronic databases including PubMed, Medline, Medscape, ScienceDirect, StatPearls, BMC Oral Health and the Cochrane Library were searched with the keywords "Oral Potentially Malignant Disorders"; "Saudi Arabia"; and "Oral Cancer". Identified articles were reviewed independently by 2 reviewers against defined inclusion and exclusion criteria. Results: 16 studies were included in this review. The prevalence of OPMDs in KSA varies significantly depending on age, gender, social habits, background disease and dental status. Conclusions: This review highlights the need for up-to-date data on the prevalence, distribution, and characteristics of OPMDs in KSA. The diverse prevalence rates and distinct characteristics of various OPMDs emphasise the necessity for targeted preventive measures. As the data on OPMDs in KSA remains limited, future research efforts should prioritise the establishment of comprehensive epidemiological studies to inform effective public health interventions in this region.

A scientometric study of chemical carcinogen-induced experimental oral carcinogenesis with emphasis on chemopreventive agents

Background/purpose

4-Nitroquinoline 1-oxide (4NQO)-induced tongue carcinoma and 7,12-dimethlybenz(a)anthracene (DMBA)-induced cheek pouch carcinoma are the most common and classical chemical carcinogen-induced animal models of oral carcinogenesis. The purpose of this study was to provide the research trends and characteristics of 4NQO- and DMBA-induced experimental oral carcinogenesis.

Materials and methods

The papers on both 4NQO- and DMBA-induced experimental oral carcinogenesis were published since 1962. All the eligible papers were retrieved on 12 May 2023 from the Scopus database.

Results

There were 506 and 349 papers on 4NQO- and DMBA-induced experimental oral carcinogenesis with 10,152 and 6306 citations, respectively. The common distinctive keywords such as rat, tongue neoplasms, drinking water, tumor microenvironment, and cyclooxygenase (COX)-2 were identified in the papers on 4NQO; and the common keywords such as hamster, cheek pouch, lipid peroxidation, glutathione, antioxidants, and topical drug administration were identified in the papers on DMBA. Importantly, 105 and 65 potential chemopreventive agents were identified from the papers on 4NQO and DMBA, respectively. Furthermore, 15 promising agents such as COX-2 inhibitor, curcumin, garlic were researched concurrently in both the two animal models.

Conclusion

This study for the first time reports the scientometric characteristics of 4NQO- and DMBA-induced experimental oral carcinogenesis. Importantly, we identify a valuable profile for oral cancer chemopreventive agents, which will aid researchers and investigators in studying oral cancer chemoprevention.

Evaluating photodynamic therapy for oral precancerous lesions: Highlighting outcome measure of malignant transformation

The main outcome measure assessed in previous studies on photodynamic therapy (PDT) for oral precancerous lesions (OPL) is clinical response based on the alteration in lesion size after treatment. However, the primary and secondary outcome measures of the interventions for OPL should be malignant transformation and recurrence. Thus, the objective of this short communication is to summarize the evidence on PDT in preventing the recurrence and malignant transformation of OPL. There were 16 eligible studies which addressed the issue of OPL patients who received PDT with recurrence outcome, and the pooled recurrence rate (95% confidence interval) was analyzed to be 20.1% (16.2-24.6%). Notably, only 1 study reported that 7.5% of malignant transformation rate for OPL received PDT. These should be interpreted with caution due to low-level evidence, such as differences in study design, clinical and pathological features of patients enrolled, limited sample size, short follow-up time. Given few evaluated the effect of PDT on malignant transformation, we highlight that this primary outcome measure of OPL needs to be investigated in further well-designed longitudinal studies with adequate follow-up periods.

Cryotherapy for oral potentially malignant disorders

Four surgical treatment modalities namely cryosurgery, scalpel and blade surgery, diode LASER surgery and CO2 LASER surgery in the management of oral potentially malignant disorders (OPMDs) in terms of healing outcomes post operatively and recurrence is evaluated. The study included sixty outpatients whose biopsies revealed OPMDs (oral lichen planus, homogeneous leukoplakia, non-homogenous leukoplakia and erythroplakia). There is decrease in post-operative pain and oedema in all four treatment categories at one week follow up and two week follow up. It was observed that pain was low in cryosurgery treatment category at day of surgery as well as at one week of follow up as compared to diode LASER and CO2 LASER. Observations from the study highlights that all four surgical modalities used in this study were effective for treatment of OPMDs, and the overall summation of the results of the study showed that cryotherapy seems to offer better clinically significant results than laser therapy.

Management of zygomatic fractures using different surgical approaches

Management of zygomatic complex fractures using closed reduction, two point open reduction with internal fixation (ORIF), closed reduction with three point ORIF and two point ORIF is of interest to dentist. 150 patients with zygomatic bone fractures between the ages of 14-60 years were included in the study. At final assessment, the percentage of stable condition was greater in closed reduction + two point ORIF and closed reduction + three point ORIF when compared to two point ORIF alone and three point ORIF alone and closed reduction alone. It was observed that stable condition was lowest in closed reduction alone. It was also observed that stable condition was lower in closed reduction + two point ORIF as compared to closed reduction + three point ORIF. It was also further noticed that stable condition was lower in two point ORIF alone as compared to three point ORIF alone. The treatment approach involving closed reduction and three point ORIF had better outcomes for management of zygomatic complex fractures.

Oral Leukoplakia. A Five-Year Follow-Up Study

Background: Oral leukoplakia (OLK) is the most studied oral potentially malignant disorders in the scientific literature. Its malignant transformation (MT) rate varies between 1.1% and 40.8%, depending on the type of study and population group studied. There is no universal agreement to treat or manage these lesions, so it is up to each clinician's experience and expertise in how he/she manages these patients. Objective:The aim of this retrospective study was to assess the clinical aspects and pattern of evolution of OLK in 30 patients five years or more after the initial diagnosis. Material and methods:We selected 30 OLK patients from our database. Demographic, clinical and evolutive data was retrieved from the medical files. The following variables were analysed: age and sex, smoking habits, clinical features (form, dimension, site of the lesion), result of mycological examination, treatment and outcomes of the lesions over a follow-up of more than five years. Results:For a follow-up of 119.63 months, we detected a value of 0.2% MT rate per year. Outcomes varied from the complete disappearance of the lesion to recurrence and malignant transformation with a variety of treatment methods applied. Conclusion:Despite the low MT rate for a long follow-up, it is hard to say which treatment method is the best, due to the heterogeneity of the clinical aspects of the lesions and because there is no standardised test method, either genetic testing or immunohistochemical testing. We recommend a varied approach, suitable for each patient's needs and medical context, always when possible histopathological confirmation for grading epithelial dysplasia, which remains the most reliable method of checking the process of malignant transformation.

Nutrigenomics and microbiome shaping the future of personalized medicine: a review article

The relationship between nutrition and genes has long been hinted at and sometimes plainly associated with certain diseases. Now, after many years of research and coincidental findings, it is believed that this relationship, termed "Nutrigenomics," is certainly a factor of major importance in various conditions. In this review article, we discuss nutrigenomics, starting with basics definitions and enzymatic functions and ending with its palpable association with cancer. Now, diet is basically what we eat on a daily basis. Everything that enters through our alimentary tract ends up broken down to minute molecules and amino acids. These molecules interact with our microbiome and genome in discreet ways. For instance, we demonstrate how proper intake of probiotics enhances beneficial bacteria and may alleviate IBS and prevent colorectal cancer on the long term. We also show how a diet rich in folic acid is essential for methylenetetrahydrofolate reductase (MTHFR) function, which lowers risk of colorectal cancer. Also, we discuss how certain diets were associated with development of certain cancers. For example, red and processed meat are highly associated with colorectal and prostate cancer, salty diets with stomach cancer, and obesity with breast cancer. The modification of these diets significantly lowered the risk and improved prognosis of these cancers among many others. We also examined how micronutrients had a role in cancer prevention, as vitamin A and C exert anti-carcinogenic effects through their function as antioxidants. In addition, we show how folic acid prevent DNA mutations by enhancing protein methylation processes. Finally, after a systematic review of myriad articles on the etiology and prevention of cancer, we think that diet should be a crucial feature in cancer prevention and treatment programs. In the future, healthy diets and micronutrients may even be able to successively alter the liability to genetic mutations that result in cancer. It also will play a role in boosting treatment and improving prognosis of diagnosed cancers.

Oral leukoplakia classification and staging system with incorporation of differentiated dysplasia

OBJECTIVES

A classification and staging system for oral leukoplakia (OL) was introduced to promote uniform reporting. In this system, size and the histopathologic diagnosis are assessed and combined in a staging system. The various stages could be predictive for malignant transformation of OL. Differentiated dysplasia (DD) was recently recognized as an important architectural pattern of dysplasia and is highly associated with malignant transformation (MT) of OL. In the present study, DD was incorporated in the OL-system. The aim of the present study was to test the adapted system on a cohort of patients with OL.

PATIENT AND METHODS

The group consisted of 140 patients. The size, absence or presence and degree of classic dysplasia (CD) and DD were incorporated into the OL-system.

RESULTS

In 31/140 patients, MT occurred. Size was not statistically significant with MT (p = 0.422). The presence of dysplasia was predictive for MT (p = 0.003), whereby severe CD and DD were highly statistically significant for MT (p = 0.008). Stage IV was statistically significant for MT (p = 0.011).

CONCLUSIONS

The present study emphasizes the value of the slightly modified OL-system with incorporation of DD in uniform reporting of OL and the value in predicting MT.

Importance of the vaporization margin during CO2 laser treatment of oral leukoplakia: A survival study

OBJECTIVES

The main purpose of this study was to assess the response of oral leukoplakia to CO2 laser vaporization treatment, as well as determining possible factors that may affect recurrence of lesions.

MATERIALS AND METHODS

A retrospective study was conducted, in which the medical records of patients who had been clinically and histologically diagnosed with oral leukoplakia and treated with CO2 laser between 1996 and 2019 at the Oral Medicine Teaching Unit of the Faculty of Dentistry of the University of Santiago de Compostela were reviewed.

RESULTS

Fifty-eight patients were included: 36 female and 22 male subjects, with a mean age of 63.7 years old (SD ±13.1). The average follow-up time was 57.5 months (SD ±57.9). A relapse rate of 52.6% was determined. Of all the studied variables, the margin was the only one for which a statistically significant association with recurrence of lesions was demonstrated (p < 0.05).

CONCLUSION

The vaporization of lesions using CO2 laser with a safety margin of at least 3 mm from the clinical limits of OL is a key factor in preventing recurrence.

Evaluating surgical excision to prevent progression of oral precancerous lesions: Highlighting randomized controlled trials and cohort studies

Currently, surgical excision remains a common intervention for oral precancerous lesions (OPL). However, the studies focusing on conventional surgery by scalpel for OPL are not analyzed collectively in detail. Therefore, the objective of this short communication is to summarize and evaluate the evidence on scalpel surgery in preventing the progression of OPL patients. There are 16 eligible studies on surgery management of the recurrence (13 studies) or malignant transformation (13 studies) of OPL. The pooled recurrence rate (95% confidence interval) of OPL patients received scalpel surgery and laser therapy is 29.5% (26.3-33.0%) and 32.2% (26.1-38.9%), respectively. The pooled rate of malignant transformation of OPL patients received scalpel surgery, laser therapy, and clinical observation is 8.9% (7.3-10.9%), 6.0% (3.5-10.1%), and 10.2% (8.6-12.1%), respectively. The important limitation of current evidence available for prognosis of dysplastic OPL is based on retrospective observational studies. It highlights that surgical management of OPL needs more randomized controlled trials and cohort studies to explore more reliable methods for routine clinical use to facilitate high- or low-risk stratification and further select more appropriate treatment option.

The potential roles of cigarette smoke-induced extracellular vesicles in oral leukoplakia

BACKGROUND

The onset of oral leukoplakia (OLK), the most common oral lesion with a high risk of malignant transformation, is closely associated with the exposure of cigarette smoke. Cigarette smoke is a complicated mixture of more than 4500 different chemicals including various oxidants and free radical, which contributes to the onset of immune and inflammatory response or even carcinogenesis. Recent studies have proved that the exposure of cigarette smoke leads to the onset and aggravation of many diseases via significantly changed the production and components of extracellular vesicles. The extracellular vesicles are membrane-enclosed nanosized particles secreted by diverse cells and involved in cell-cell communication because of their ability to deliver a number of bioactive molecules including proteins, lipids, DNAs and RNAs. Getting insight into the mechanisms of extracellular vesicles in regulating OLK upon cigarette smoke stimulation contributes to unravel the pathophysiology of OLK in-depth. However, evidence done on the role of extracellular vesicles in cigarette smoke-induced OLK is still in its infancy.

MATERIALS AND METHODS

Relevant literatures on cigarette smoke, oral leukoplakia and extracellular vesicles were searched in PubMed database.

CONCLUSIONS

In this review, we summarize the recent findings about the function of extracellular vesicles in the pathogenesis of cigarette smoke-induced diseases, and to infer their potential utilizations as diagnostic biomarkers, prognostic evaluation, and therapeutic targets of OLK in the future.

Management of oral leukoplakia with an 808-nm high-power diode laser: a single-center experience

PURPOSE

High-power diode laser emerges as a promising approach to the treatment of oral leukoplakia (OL); however, its short- and long-term effects have been barely explored. This study evaluated the postoperative endpoints and the recurrence rate of high-power diode laser treatment in a well-defined series of patients with OL.

METHODS

A prospective analysis was performed on 22 individuals comprising 31 OL. The lesions were irradiated using the following protocol: Indium-Gallium-Arsenide diode laser, 808 nm, continuous-wave mode, 1.5-2.0 W, 780.0 ± 225.1 J, and 477.1 ± 131.8 s. Postoperative pain was assessed with a visual analog scale at three endpoints. Clinical follow-up was performed on all patients and the Kaplan-Meier test was used to analyze the probability of recurrence.

RESULTS

The series consisted mostly of women (72.7%) with a mean age of 62.8 years. A single laser session was performed in 77.4% of cases. The median score on the scale that assessed pain on the 1st, 14th and 42nd postoperative day was 4, 1, and 0, respectively. The mean follow-up period per lesion was 28.6 months (range: 2-53 months). A complete response was observed in 93.5% of OL cases, while 6.5% had recurrence. The probability of recurrence at 39 months was 6.7%. No patient experienced malignant transformation.

CONCLUSION

High-power diode laser for the treatment of OL is safe and effective during the trans- and postoperative period. These findings represent an alternative approach to the management of OL, mainly because a low recurrence rate was observed.

CDH4 inhibits ferroptosis in oral squamous cell carcinoma cells

BACKGROUND

The cadherin-4 gene (CDH4), a member of the cadherin family genes, encodes R-cadherin (R-cad); however, the function of this gene in different types of cancer remains controversial. The function of CDH4 in OSCC (oral squamous cell carcinoma) is unknown.

MATERIALS AND METHODS

We use the Cancer Genome Atlas (TCGA) database to find the expression of CDH4 in OSCC is more than normal tissue. Our tissue samples also confirmed that CDH4 gene was highly expressed in OSCC. The related cell function assay detected that CDH4 promotes the ability of cell proliferation, migration, self-renewal and invasion. Cell staining experiment confirmed that the change of CDH4 expression would change the cell mortality. The western blot of GPX4 (glutathione-dependent peroxidase-4), GSH (reduced glutathione) test assay and MDA(Malondialdehyde) test assay show that the expression of CDH4 may resist the sensitivity of ferropotosis in OSCC.

RESULTS

CDH4 was upregulated in OSCC samples and was correlation with poor survival of patients. High expression of CDH4 effectively promotes the proliferation, mobility of OSCC cells and reduce the sensitivity of OSCC cells to ferroptosis. CDH4 is positively correlated with EMT pathway genes, negatively correlated with fatty acid metabolism pathway genes and peroxisome pathway genes, and positively correlated with ferroptosis suppressor genes in OSCC.

CONCLUSIONS

These results indicate that CDH4 may play a positive role in tumor progression and resistance ferroptosis and may be a potential therapeutic target for OSCC.

Recurrence of Oral Leukoplakia after CO2 Laser Resection: A Prospective Longitudinal Study

AIM

The aim of this study is to assess the efficacy of CO2 laser treatment in oral leukoplakia and to analyse the recurrence rate of oral leukoplakia lesions at 18-month follow-up.

MATERIALS AND METHODS

A prospective clinical study regarding CO2 laser treatment for oral leukoplakia was conducted, in which 39 patients with a total of 53 oral leukoplakias were included. Follow-up was performed at 18 months post-surgery and the following variables were studied: sex, age, associated risk factors, clinical classification, size, location and presence of epithelial dysplasia, recurrence, and rate of malignant transformation after resection.

RESULTS

In the analysis of the final results 18 months after baseline, a treatment success rate of 43.75% was observed. Oral leukoplakia recurred in 54.17% of cases, and 2.08% of leukoplakias progressed to cancer. Among all the studied variables (age, tobacco use, size, location, clinical type or histology), no significant differences were found with regard to recurrence.

CONCLUSION

The use of CO2 laser therapy to treat leukoplakia lesions is sufficient to remove such lesions. However, parameters that can assess recurrence need to be sought.

Three-Dimensional Printing of an Apigenin-Loaded Mucoadhesive Film for Tailored Therapy to Oral Leukoplakia and the Chemopreventive Effect on a Rat Model of Oral Carcinogenesis

Oral leukoplakia, which presents as white lesions in the oral cavity, including on the tongue, is precancerous in nature. Conservative treatment is preferable, since surgical removal can markedly reduce the patient’s quality of life. In the present study, we focused on the flavonoid apigenin as a potential compound for preventing carcinogenesis, and an apigenin-loaded mucoadhesive oral film was prepared using a three-dimensional (3D) bioprinter (semi-solid extrusion-type 3D printer). Apigenin-loaded printer inks are composed of pharmaceutical excipients (HPMC, CARBOPOL, and Poloxamer), water, and ethanol to dissolve apigenin, and the appropriate viscosity of printer ink after adjusting the ratios allowed for the successful 3D printing of the film. After drying the 3D-printed object, the resulting film was characterized. The chemopreventive effect of the apigenin-loaded film was evaluated using an experimental rat model that had been exposed to 4-nitroquinoline 1-oxide (4NQO) to induce oral carcinogenesis. Treatment with the apigenin-loaded film showed a remarkable chemopreventive effect based on an analysis of the specimen by immunohistostaining. These results suggest that the apigenin-loaded mucoadhesive film may help prevent carcinogenesis. This successful preparation of apigenin-loaded films by a 3D printer provides useful information for automatically fabricating other tailored films (with individual doses and shapes) for patients with oral leukoplakia in a future clinical setting.

Efficacy of Topical Intervention for Recurrent Aphthous Stomatitis: A Network Meta-Analysis

Background and objectives: To compare the efficacy and safety of topical interventions used for recurrent aphthous stomatitis. Materials and Methods: This network meta-analysis was conducted in accordance with the PRISMA statement. We searched four electronic databases, PubMed, Web of Science (WOS), Cochrane Central Register of Controlled Trials and Embase, for randomized controlled trials reporting efficacy and safety data on topical interventions for recurrent aphthous stomatitis. We performed a quality evaluation using a methodology based on the Cochrane Handbook. Two authors independently extracted data on healing effect, size reduction effect, symptom reduction effect, recurrence and safety assessment. Network meta-analysis was then performed using ADDIS and RevMan. Results: A total of 72 trials (5272 subjects) involving 29 topical interventions were included. Honey, lnsulin liposome gel, laser, amlexanox, glycyrrhiza and triamcinolone had better efficacy performance. Probiotics and chlorhexidine helped to prolong ulcer intervals and reduce recurrence. Doxycycline and penicillin had a high risk of adverse events. Hematologic evaluation showed no preference. The rank possibility of size-reducing effect and symptom-reducing effect supported the short-term effect of laser and the long-term effect of probiotics. Conclusions: We recommend the use of laser as a short-term intervention during the exacerbation phase of RAS and probiotics as a long-term intervention during the exacerbation and remission phases of RAS.

Application of 5-aminolevulinic acid-mediated Waterlase-assisted photodynamic therapy in the treatment of oral leukoplakia

Photodynamic therapy (PDT) is an alternative microinvasive approach with satisfying results in the treatment of oral leukoplakia (OL). PDT combined with laser irradiation shows promise, safety and efficacy in treating OL. The efficacy of waterlase (YSGG) combined with PDT was studied by brush and tissue biopsy. Seventy-one patients with histologically diagnosed OL were enrolled, including patients with mild to moderate dysplasia, severe dysplasia and various dysplastic tissues. Patients were evaluated at baseline (t0), the end of treatment (t1) and 1 year later (t2). At t1, PDT showed a significant therapeutic effect on OL with mild to moderate dysplasia. Clinical and histological examinations revealed 60 cases (84.51%) of complete remission and 11 cases (15.49%) of partial remission. On brush biopsy, all PDT-treated patients showed reduced aneuploidy and normal histological findings. Unfortunately, at t2, 9 patients relapsed with OL, which may be related to continued smoking and betel nut chewing. At t2, 5 patients developed new severe epithelial dysplasia and even carcinoma in situ in other areas, mostly the tongue. ALA-mediated PDT combined with YSGG is effective in treating OL, particularly that with mild to moderate dysplasia. However, severe dysplasia may present undesirable effects, and the mechanism remains to be further investigated. ALA-mediated PDT combined with YSGG provides a new method for OL treatment.

Recurrent copy number alterations involving EGFR, CDKN2A, and CCND1 in oral premalignant lesions

Background

A major challenge in the management of patients with oral leukoplakia is the difficulty to identify patients at high risk of developing oral squamous cell carcinoma. Our knowledge about genomic alterations in oral leukoplakia, and in particular those that progress to oral squamous cell carcinoma, is scarce and there are no useful biomarkers that can predict the risk of malignant transformation.

Methods

Using a novel, custom‐made tissue microarray including 28 high‐risk oral leukoplakias and the corresponding oral squamous cell carcinomas from 14 cases that progressed to cancer, we assayed copy number alterations involving the oral squamous cell carcinoma driver genes CDKN2A, CCND1, EGFR, and MYC by fluorescence in situ hybridization. The copy number alterationss were correlated with clinicopathological data from all patients.

Results

Copy number alterations were identified in 14/24 oral leukoplakias, analyzable for one or more of the oral squamous cell carcinoma driver genes. EGFR was the most frequently altered gene in oral leukoplakias with amplification/gain in 43.5% followed by loss of CDKN2A (26.1%), gains of CCND1 (26.1%), and MYC (8.3%). Losses of CDKN2A were more common in oral leukoplakias progressing to oral squamous cell carcinoma compared to those that did not. Copy number alterations were more common in oral squamous cell carcinomas than in oral leukoplakias.

Conclusions

Our findings demonstrate that copy number alterations involving the oral squamous cell carcinoma drivers CDKN2A, EGFR, and CCND1 occur in oral leukoplakias and suggest a possible role for these genes in the development and/or progression of subsets of oral leukoplakias.

Oral Potentially Malignant Disorders: Etiology, Pathogenesis, and Transformation Into Oral Cancer

Among oral diseases, oral cancer is a critical health issue due to its life-threatening potential. Globocan, in its 2020 report, estimated ∼0.37 million new cases of oral cancer, with the majority of them coming from the Asian continent. The WHO has anticipated a rise in the incidences of oral cancer in the coming decades. Various factors, such as genetic, epigenetic, microbial, habitual, and lifestyle factors, are closely associated with oral cancer occurrence and progression. Oral lesions, inherited genetic mutations (dyskeratosis congenital syndrome), and viral infections (HPV) are early signs of oral cancer. Lesions with dysplastic features have been categorized under oral potentially malignant disorders (OPMDs), such as oral leukoplakia, erythroplakia, oral submucous fibrosis (OSMF), and proliferative verrucous leukoplakia, are assumed to have a high risk of malignancy. The incidence and prevalence of OPMDs are recorded as being high in South-Asian countries. Early detection, prevention, and treatment of OPMDs are needed to prevent its malignant transformation into oral cancer. Many advanced diagnostic techniques are used to predict their progression and to assess the risk of malignant transformation. This communication provides insight into the importance of early detection and prevention of OPMDs.

Unmet Needs and Perspectives in Oral Cancer Prevention

Oral potentially malignant disorders (OPMD) may precede oral squamous cell carcinoma (OSCC). Reported rates of malignant transformation of OPMD range from 3 to 50%. While some clinical, histological, and molecular factors have been associated with a high-risk OPMD, they are, to date, insufficiently accurate for treatment decision-making. Moreover, this range highlights differences in the clinical definition of OPMD, variation in follow-up periods, and molecular and biological heterogeneity of OPMD. Finally, while treatment of OPMD may improve outcome, standard therapy has been shown to be ineffective to prevent OSCC development in patients with OPMD. In this perspective paper, several experts discuss the main challenges in oral cancer prevention, in particular the need to (i) to define an OPMD classification system by integrating new pathological and molecular characteristics, aiming (ii) to better identify OPMD at high risk of malignant transformation, and (iii) to develop treatment strategies to eradicate OPMD or prevent malignant transformation.

Molecular Signatures of Tumour and Its Microenvironment for Precise Quantitative Diagnosis of Oral Squamous Cell Carcinoma: An International Multi-Cohort Diagnostic Validation Study

BACKGROUND

Heterogeneity in oral potentially malignant disorder (OPMD) poses a problem for accurate prognosis that impacts on treatment strategy and patient outcome. A holistic assessment based on gene expression signatures from both the tumour cells and their microenvironment is necessary to provide a more precise prognostic assessment than just tumour cell signatures alone.

METHODS

We reformulated our previously established multigene qPCR test, quantitative Malignancy Index Diagnostic System (qMIDS) with new genes involved in matrix/stroma and immune modulation of the tumour microenvironment. An algorithm calculates and converts a panel of 16 gene mRNA expression levels into a qMIDS index to quantify risk of malignancy for each sample.

RESULTS

The new qMIDS^V2 assay was validated in a UK oral squamous cell carcinoma (OSCC) cohort (n = 282) of margin and tumour core samples demonstrating significantly better diagnostic performance (AUC = 0.945) compared to previous qMIDS^V1 (AUC = 0.759). Performance of qMIDS^V2 were independently validated in Chinese (n = 35; AUC = 0.928) and Indian (n = 95; AUC = 0.932) OSCC cohorts. Further, 5-year retrospective analysis on an Indian dysplastic lesion cohort (n = 30) showed that qMIDS^V2 was able to significantly differentiate between lesions without transformation and those with malignant transformation.

CONCLUSIONS

This study validated a novel multi-gene qPCR test on a total of 535 tissue specimens from UK, China and India, demonstrating a rapid minimally invasive method that has a potential application for dysplasia risk stratification. Further study is required to establish if qMIDS^V2 could be used to improve OPMD patient management, guide treatment strategy and reduce oral cancer burden.

Genetic Changes Driving Immunosuppressive Microenvironments in Oral Premalignancy

Oral premalignant lesions (OPLs) are the precursors to oral cavity cancers, and have variable rates of progression to invasive disease. As an intermediate state, OPLs have acquired a subset of the genomic alterations while arising in an oral inflammatory environment. These specific genomic changes may facilitate the transition to an immune microenvironment that permits malignant transformation. Here, we will discuss mechanisms by which OPLs develop an immunosuppressive microenvironment that facilitates progression to invasive cancer. We will describe how genomic alterations and immune microenvironmental changes co-evolve and cooperate to promote OSCC progression. Finally, we will describe how these immune microenvironmental changes provide specific and unique evolutionary vulnerabilities for targeted therapies. Therefore, understanding the genomic changes that drive immunosuppressive microenvironments may eventually translate into novel biomarker and/or therapeutic approaches to limit the progression of OPLs to potential lethal oral cancers.

Dietary Carotenoids in Head and Neck Cancer-Molecular and Clinical Implications

Head and neck cancer (HNC) is one of the most common cancers in the world according to GLOBCAN. In 2018, it was reported that HNC accounts for approximately 3% of all human cancers (51,540 new cases) and is the cause of nearly 1.5% of all cancer deaths (10,030 deaths). Despite great advances in treatment, HNC is indicated as a leading cause of death worldwide. In addition to having a positive impact on general health, a diet rich in carotenoids can regulate stages in the course of carcinogenesis; indeed, strong epidemiological associations exist between dietary carotenoids and HNS, and it is presumed that diets with carotenoids can even reduce cancer risk. They have also been proposed as potential chemotherapeutic agents and substances used in chemoprevention of HNC. The present review discusses the links between dietary carotenoids and HNC. It examines the prospective anticancer effect of dietary carotenoids against intracellular cell signalling and mechanisms, oxidative stress regulation, as well as their impact on apoptosis, cell cycle progression, cell proliferation, angiogenesis, metastasis, and chemoprevention; it also provides an overview of the limited preclinical and clinical research published in this arena. Recent epidemiological, key opinion-forming systematic reviews, cross-sectional, longitudinal, prospective, and interventional studies based on in vitro and animal models of HNC also indicate that high carotenoid content obtained from daily supplementation has positive effects on the initiation, promotion, and progression of HNC. This article presents these results according to their increasing clinical credibility.

[The use of photodynamic therapy in patients with severe forms of leukoplakia]

OBJECTIVE

The aim the study is to increase the effectiveness of the treatment of severe forms of leukoplakia with the use of photodynamic therapy.

MATERIAL AND METHODS

120 patients with severe forms of leukoplakia were examined. 30 patients were diagnosed with Cr and carcinoma in situ, and therefore they were excluded from the study. In 90 patients, the diagnosis was confirmed by histological and IHC studies. Before the use of photodynamic therapy, the degree of saturation of pathological foci with a photosensitizer was determined by the method of fluorescent diagnostics using the LED device «RFS-400».

RESULTS

As a result of treatment with photodynamic therapy using a 2nd generation photosensitizer («Photoditazine» 0.5% gel penetrator), a significant improvement in the epithelization of lesion elements was observed: in 92% of patients with verrucous leukoplakia and in 83% of patients with erosive leukoplakia.

CONCLUSION

The use of photodynamic therapy for the treatment of patients with complicated forms of leukoplakia is an effective method of treatment for this pathology.

Clinical assessment for the detection of oral cavity cancer and potentially malignant disorders in apparently healthy adults

BACKGROUND

The early detection of oral cavity squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD), followed by appropriate treatment, may improve survival and reduce the risk for malignant transformation respectively. This is an update of a Cochrane Review first published in 2013.

OBJECTIVES

To estimate the diagnostic test accuracy of conventional oral examination, vital rinsing, light-based detection, mouth self-examination, remote screening, and biomarkers, used singly or in combination, for the early detection of OPMD or OSCC in apparently healthy adults.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 20 October 2020), MEDLINE Ovid (1946 to 20 October 2020), and Embase Ovid (1980 to 20 October 2020). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. We conducted citation searches, and screened reference lists of included studies for additional references.

SELECTION CRITERIA

We selected studies that reported the test accuracy of any of the aforementioned tests in detecting OPMD or OSCC during a screening procedure. Diagnosis of OPMD or OSCC was provided by specialist clinicians or pathologists, or alternatively through follow-up.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance. Eligibility, data extraction, and quality assessment were carried out by at least two authors independently and in duplicate. Studies were assessed for methodological quality using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). We reported the sensitivity and specificity of the included studies. We provided judgement of the certainty of the evidence using a GRADE assessment.

MAIN RESULTS

We included 18 studies, recruiting 72,202 participants, published between 1986 and 2019. These studies evaluated the diagnostic test accuracy of conventional oral examination (10 studies, none new to this update), mouth self-examination (four studies, two new to this update), and remote screening (three studies, all new to this update). One randomised controlled trial of test accuracy directly evaluated conventional oral examination plus vital rinsing versus conventional oral examination alone. There were no eligible studies evaluating light-based detection or blood or salivary sample analysis (which tests for the presence of biomarkers for OPMD and OSCC). Only one study of conventional oral examination was judged as at overall low risk of bias and overall low concern regarding applicability. Given the clinical heterogeneity of the included studies in terms of the participants recruited, setting, prevalence of the target condition, the application of the index test and reference standard, and the flow and timing of the process, the data could not be pooled within the broader categories of index test. For conventional oral examination (10 studies, 25,568 participants), prevalence in the test accuracy sample ranged from 1% to 51%. For the seven studies with prevalence of 10% or lower, a prevalence more comparable to the general population, the sensitivity estimates were variable, and ranged from 0.50 (95% confidence interval (CI) 0.07 to 0.93) to 0.99 (95% CI 0.97 to 1.00); the specificity estimates were more consistent and ranged from 0.94 (95% CI 0.88 to 0.97) to 0.99 (95% CI 0.98 to 1.00). We judged the overall certainty of the evidence to be low, and downgraded for inconsistency and indirectness. Evidence for mouth self-examination and remote screening was more limited. We judged the overall certainty of the evidence for these index tests to be very low, and downgraded for imprecision, inconsistency, and indirectness. We judged the evidence for vital rinsing (toluidine blue) as an adjunct to conventional oral examination compared to conventional oral examination to be moderate, and downgraded for indirectness as the trial was undertaken in a high-risk population.

AUTHORS' CONCLUSIONS

There is a lack of high-certainty evidence to support the use of screening programmes for oral cavity cancer and OPMD in the general population. Frontline screeners such as general dentists, dental hygienists, other allied professionals, and community healthcare workers should remain vigilant for signs of OPMD and OSCC.

Expression of p53, p63, podoplanin and Ki-67 in recurring versus non-recurring oral leukoplakia

Oral leukoplakia (OL), a potentially malignant disorder, recurs in 40% of cases after surgical removal. Recurrence is a risk factor for malignant transformation. We aimed to examine the prognostic significance of four biomarkers related to cell proliferation: p53, p63, podoplanin (PDPN) and Ki-67 in predicting recurrence. Formalin-fixed-paraffin-embedded specimens from excised OL (n = 73, 33 recurrent; 40 non-recurrent) were collected in a prospective study. Immunohistochemistry was used to visualise expression of p53, p63, PDPN and Ki-67. Image analysis software was used for quantification of p53-, p63- and Ki-67-expressing cells, while PDPN was analysed visually. The expression of all four proteins were higher in recurrent compared with non-recurrent OL, only expression of p53 was statistically significant. In uni- and multivariable Cox regression analyses of individual markers, expression of p63 was significantly associated with higher recurrence risk (p = 0.047). OL with a combined high expression of both p53 and p63 had a significantly higher risk to recur [Log Rank, p = 0.036; multivariate Cox, HR: 2.48 (1.13–5.44; p = 0.024)]. Combination of p53 and p63 expression may be used as a prognostic biomarker for recurrence of OL.

RARβ Expression in Keratinocytes from Potentially Malignant Oral Lesions: The Functional Consequences of Re-Expression by De-Methylating Agents

Simple Summary

Patients may develop white or red patches of the lining of the mouth with an increased risk of developing oral cancer. Treatment with Vitamin A derivatives (retinoids) results in some improvement in these lesions, but this is not maintained, and there are side effects. We know that the cells of the mouth lose cellular receptors for retinoids as these lesions develop, initially by a reversible alteration to the DNA (DNA methylation). Drugs, such as 5-AZA-CdR, which reduce DNA methylation, may restore sensitivity to the effects of retinoids. Treatment of a panel of cells from mouth precancer white patches with retinoids, 5-AZA-CdR and a combination results in varied responses: some cells re-sensitise to retinoids, whereas in others, the main effects on cell division rate and cell lifespan seem related to the effects of 5-AZA-CdR alone. These findings help us to understand the varied responses to retinoids in the clinical setting.

Abstract

Loss of RARβ2 expression by promoter methylation is an early event in oral carcinogenesis. Understanding the mechanisms and consequences of RARβ loss may aid in understanding the disappointing results of retinoid chemoprevention trials. This study aimed to describe the effects of all-trans retinoic acid (ATRA) and the de-methylating agent 5-Aza-2′ deoxycytidine (5-AZA-CdR) on a panel of immortal potentially malignant oral lesion (PMOL) cell cultures. RARβ expression was assessed in PMOL tissues by immunohistochemistry. Cells were treated with ATRA ± 5-AZA-CdR, and the effects on the cell cycle and senescence were assessed. In PMOL tissues, RARβ expression was variable, but lower in biopsies which gave rise to immortal cell cultures. Treatment of iPMOL cells with ATRA resulted in little change in RARβ expression, but the addition of 5-AZA-CdR resulted in significant increases. The effects on the cell cycle and senescence were variable and may be related to 5-AZA-CdR, as this has wider effects on the cell cycle. Overall, the response of iPMOL cells to ATRA and 5-AZA-CdR treatment was variable and is dependent on several factors, including RARβ-promoter methylation. These findings may help to explain the lack of consistent effect of retinoids in PMOLs seen in chemoprevention trials.

An active surveillance program in oral preneoplasia and translational oncology benefit

OBJECTIVE

We desired to establish an active surveillance clinic for head and neck cancer. In this review we examined.

METHODS

We examined the natural history of human oral carcinogenesis, the types of preneoplastic lesions, and efforts at oral chemoprevention over the past decades for presentation here.

RESULTS

We established a clinic and program for patients with oral premalignant lesions approximately over 15 years ago based on an unmetneed for this service. We have completed over 4000 outpatient visits for this cohort and have a place for referrals of difficult oral lesions. We have leveraged this population for multiple federally funded trials on oral cancer prevention as well as specimen banking.

CONCLUSION

There is need for routine active surveillance for oral preneoplastic conditions in patients at high risk for conversion to cancer. There are no effective durable treatment or preventions for these individuals and we have attempted to fill this unmet need with our program.

Early-Phase Interventional Trials in Oral Cancer Prevention

Simple Summary

Oral cancer is a devastating disease with increasing incidence worldwide. Oral epithelial dysplasia (OED) is a potentially malignant disorder and patients with OED are at increased risk of developing oral cancer. Current strategies for management of OED include surgery or close observation and both fail to address the underlying pathogenesis of the disease. There is an urgent need for evidence-based medical treatments for OED to prevent oral cancer development in this cohort. Chemoprevention trials to date have not delivered therapeutic agents for routine clinical practice. Historically, there has been significant heterogeneity in the design of oral cancer chemoprevention trials, with most failing to selectively recruit patients with biopsy-proven OED, which limits the usefulness of the findings in the OED population. The present paper aims to review the current evidence and the methodology of early-phase trials in oral cancer chemoprevention. Novel strategies in oral cancer chemoprevention will also be discussed.

Abstract

The increasing breadth of molecular targets, promise of immune-targeted therapies and repurposed agents have heightened interest in cancer prevention. While, to date, testing of oral cancer chemoprevention strategies has failed to deliver therapeutic agents for routine clinical practice, there remains an urgent need for further clinical research to overcome this hurdle. Patients at the greatest risk of disease stand to benefit the most from inclusion in clinical trials; therefore, there is a need to carefully define this population using validated clinical and molecular markers. Safety, tolerability and the efficacy of interventions is assessed through carefully selected endpoints. These endpoints may include pharmacodynamic, clinical, histological and on-target molecular modifications as an individual or as a composite endpoint. Early-phase trials provide an area of opportunity to explore novel and repurposed agents in the setting of oral cancer chemoprevention, eventually leading to phase III trials with clinical endpoints such as transformation and clinical outcome; these studies are large, lengthy and expensive and should be reserved for the most promising of agents. This paper will explore current evidence in oral cancer chemoprevention, drug repurposing, selection of appropriate endpoints for early-phase trials and novel therapeutic angles in oral cancer chemoprevention.

Diagnostic tests for oral cancer and potentially malignant disorders in patients presenting with clinically evident lesions

BACKGROUND

Squamous cell carcinoma is the most common form of malignancy of the oral cavity, and is often proceeded by oral potentially malignant disorders (OPMD). Early detection of oral cavity squamous cell carcinoma (oral cancer) can improve survival rates. The current diagnostic standard of surgical biopsy with histology is painful for patients and involves a delay in order to process the tissue and render a histological diagnosis; other diagnostic tests are available that are less invasive and some are able to provide immediate results. This is an update of a Cochrane Review first published in 2015.

OBJECTIVES

Primary objective: to estimate the diagnostic accuracy of index tests for the detection of oral cancer and OPMD, in people presenting with clinically evident suspicious and innocuous lesions.

SECONDARY OBJECTIVE

to estimate the relative accuracy of the different index tests.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: MEDLINE Ovid (1946 to 20 October 2020), and Embase Ovid (1980 to 20 October 2020). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were also searched for ongoing trials to 20 October 2020. No restrictions were placed on the language or date of publication when searching the electronic databases. We conducted citation searches, and screened reference lists of included studies for additional references.

SELECTION CRITERIA

We selected studies that reported the diagnostic test accuracy of the following index tests when used as an adjunct to conventional oral examination in detecting OPMD or oral cavity squamous cell carcinoma: vital staining (a dye to stain oral mucosa tissues), oral cytology, light-based detection and oral spectroscopy, blood or saliva analysis (which test for the presence of biomarkers in blood or saliva).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance. Eligibility, data extraction and quality assessment were carried out by at least two authors, independently and in duplicate. Studies were assessed for methodological quality using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Meta-analysis was used to combine the results of studies for each index test using the bivariate approach to estimate the expected values of sensitivity and specificity.

MAIN RESULTS

This update included 63 studies (79 datasets) published between 1980 and 2020 evaluating 7942 lesions for the quantitative meta-analysis. These studies evaluated the diagnostic accuracy of conventional oral examination with: vital staining (22 datasets), oral cytology (24 datasets), light-based detection or oral spectroscopy (24 datasets). Nine datasets assessed two combined index tests. There were no eligible diagnostic accuracy studies evaluating blood or salivary sample analysis. Two studies were classed as being at low risk of bias across all domains, and 33 studies were at low concern for applicability across the three domains, where patient selection, the index test, and the reference standard used were generalisable across the population attending secondary care. The summary estimates obtained from the meta-analysis were: - vital staining: sensitivity 0.86 (95% confidence interval (CI) 0.79 to 0.90) specificity 0.68 (95% CI 0.58 to 0.77), 20 studies, sensitivity low-certainty evidence, specificity very low-certainty evidence; - oral cytology: sensitivity 0.90 (95% CI 0.82 to 0.94) specificity 0.94 (95% CI 0.88 to 0.97), 20 studies, sensitivity moderate-certainty evidence, specificity moderate-certainty evidence; - light-based: sensitivity 0.87 (95% CI 0.78 to 0.93) specificity 0.50 (95% CI 0.32 to 0.68), 23 studies, sensitivity low-certainty evidence, specificity very low-certainty evidence; and - combined tests: sensitivity 0.78 (95% CI 0.45 to 0.94) specificity 0.71 (95% CI 0.53 to 0.84), 9 studies, sensitivity very low-certainty evidence, specificity very low-certainty evidence.

AUTHORS' CONCLUSIONS

At present none of the adjunctive tests can be recommended as a replacement for the currently used standard of a surgical biopsy and histological assessment. Given the relatively high values of the summary estimates of sensitivity and specificity for oral cytology, this would appear to offer the most potential. Combined adjunctive tests involving cytology warrant further investigation. Potentially eligible studies of blood and salivary biomarkers were excluded from the review as they were of a case-control design and therefore ineligible. In the absence of substantial improvement in the tests evaluated in this updated review, further research into biomarkers may be warranted.

SAVER: sodium valproate for the epigenetic reprogramming of high-risk oral epithelial dysplasia-a phase II randomised control trial study protocol

Background

Sodium valproate (VPA) has been associated with a reduced risk of head and neck cancer development. The potential protective mechanism of action is believed to be via inhibition of histone deacetylase and subsequent epigenetic reprogramming. SAVER is a phase IIb open-label, randomised control trial of VPA as a chemopreventive agent in patients with high-risk oral epithelial dysplasia (OED). The aim of the trial is to gather preliminary evidence of the clinical and biological effects of VPA upon OED and assess the feasibility and acceptability of such a trial, with a view to inform a future definitive phase III study.

Methods

One hundred and ten patients with high-risk OED will be recruited from up to 10 secondary care sites in the UK and randomised into either VPA or observation only for 4 months. Women of childbearing potential will be excluded due to the teratogenic properties of VPA. Tissue and blood samples will be collected prior to randomisation and on the last day of the intervention/observation-only period (end of 4 months). Clinical measurement and additional safety bloods will be taken at multiple time points during the trial. The primary outcome will be a composite, surrogate endpoint of change in lesion size, change in grade of dysplasia and change in LOH profile at 8 key microsatellite regions. Feasibility outcomes will include recruitment targets, compliance with the study protocol and adverse effects. A qualitative sub-study will explore patient experience and perception of the trial.

Discussion

The current management options for patients with high-risk OED are limited and mostly include surgical resection and clinical surveillance. However, there remains little evidence whether surgery can effectively lead to a notable reduction in the risk of oral cancer development. Similarly, surveillance is associated with concerns regarding delayed diagnosis of OED progressing to malignancy. The SAVER trial provides an opportunity to investigate the effects of a repurposed, inexpensive and well-tolerated medication as a potential chemopreventive strategy for patients with high-risk OED. The clinical and biological findings of SAVER will inform the appropriateness, design and feasibility of a definitive phase III trial.

Trial registration

The trial is registered with the European Clinical Trials Database (Eudra-CT 2018-000197-30). (http://www.isrctn.com/ISRCTN12448611). The trial was prospectively registered on 24/04/2018.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05373-8.

Early changes in the immune microenvironment of oral potentially malignant disorders reveal an unexpected association of M2 macrophages with oral cancer free survival

Understanding the dynamics of the immune microenvironment is critical to the development of immuno-based strategies for the prevention of oral potentially malignant disorders transformation to oral squamous cell carcinoma (OSCC). We used laser capture microdissection and RNA-sequencing to profile the expression of 13 matched pairs of epithelial versus stromal compartments from normal mucosa, hyperplasia, dysplasia, and invasive tumors in the 4-nitroquinolein (4-NQO) murine model of oral carcinogenesis. Genes differentially expressed at each step of transformation were defined. Immune cell deconvolution and enrichment scores of various biological processes including immune-related ones were computed. Immunohistochemistry was also performed to characterize the immune infiltrates by T-cells (T-cells CD3+, helper CD4+, cytotoxic CD8+, regulatory FoxP3+), B-cells (B220+), and macrophages (M1 iNOS+, M2 CD163+) at each histological step. Enrichment of three independent M2 macrophages signatures were computed in 86 oral leukoplakia with available clinical outcome. Most gene expression changes were observed in the stromal compartment and related to immune biological processes. Immune cell deconvolution identified infiltration by the macrophage population as the most important quantitatively especially at the stage of dysplasia. In 86 patients with oral leukoplakia, three M2 macrophages signatures were independently associated with improved oral cancer-free survival. This study provides a better understanding of the dynamics of the immune microenvironment during oral carcinogenesis and highlights an unexpected association of M2 macrophages gene expression signatures with oral cancer free survival in patients with oral leukoplakia.