Rationale: Immunosuppressive tumor microenvironment (iTME) plays an important role in carcinogenesis, and some macrophage subsets are associated with iTME generation. However, the sub-population characterization of macrophages in oral carcinogenesis remains largely unclear. Here, we investigated the immunosuppressive status with focus on function of a macrophage subset that expressed indoleamine 2,3 dioxygenase 1 (Macro-IDO1) in oral carcinogenesis. Methods: We built a single cell transcriptome atlas from 3 patients simultaneously containing oral squamous cell carcinoma (OSCC), precancerous oral leukoplakia (preca-OLK) and paracancerous tissue (PCA). Through single-cell RNA sequencing and further validation using multicolor immunofluorescence staining and the in vitro/in vivo experiments, the immunosuppressive cell profiles were built and the role of a macrophage subset that expressed indoleamine 2,3 dioxygenase 1 (Macro-IDO1) in the malignant transformation of oral leukoplakia was evaluated. Results: The iTME formed at preca-OLK stage, as evidenced by increased exhausted T cells, Tregs and some special subsets of macrophages and fibroblasts. Macro-IDO1 was predominantly enriched in preca-OLK and OSCC, distributed near exhausted T cells and possessed tumor associated macrophage transformation potentials. Functional analysis revealed the established immunosuppressive role of Macro-IDO1 in preca-OLK and OSCC: enriching the immunosuppression related genes; having an established level of immune checkpoint score; exerting strong immunosuppressive interaction with T cells; positively correlating with the CD8-exhausted. The immunosuppression related gene expression of macrophages also increased in preca-OLK/OSCC compared to PCA. The use of the IDO1 inhibitor reduced 4NQO induced oral carcinogenesis in mice. Mechanistically, IFN-γ-JAK-STAT pathway was associated with IDO1 upregulation in OLK and OSCC. Conclusions: These results highlight that Macro-IDO1-enriched in preca-OLK possesses a strong immunosuppressive role and contributes to oral carcinogenesis, providing a potential target for preventing precancerous legions from transformation into OSCC.

UNASSIGNED: Several existing studies have shown a correlation between some of the blood and urine biomarkers and oral leukoplakia (OLK). However, the causality of this relationship remains uncertain. Thus, this study aimed to examine the causal association between 35 blood and urine biomarkers and OLK.
UNASSIGNED: Single nucleotide polymorphisms (SNPs) associated with 35 blood and urine biomarkers were selected as instrumental variables (IVs) using a two-sample Mendelian randomization(MR) study to assess the causal relationship between the biomarkers and the risk of oral leukoplakia. We used the inverse variance weighted (IVW) method as the main analysis. Furthermore, several sensitivity analyses were performed to assess heterogeneity, horizontal pleiotropy, and stability.
UNASSIGNED: Based on the selection criteria of the Inverse Variance Weighted (IVW) method, the analysis found that 5 blood and urine biomarkers were significantly associated with the development of leukoplakia, of which the results of IVW showed that abnormalities of Apolipoprotein B (Apo B), Cholesterol, Low-density Lipoprotein (LDL), Triglycerides (TG) promoted the development of oral leukoplakia, and Non Albumin Protein (NAP) had a protective effect on the development of oral leukoplakia. We then performed a Bonferroni correction for these results, and after correction Apo B was still causally associated with the development of oral leukoplakia (IVW P<0.0007), whereas the other four biomarkers could only provide some evidence of predisposition.
UNASSIGNED: Our two-sample Mendelian randomization study supports the existence of a causal relationship between these five blood and urine biomarkers and the occurrence of oral leukoplakia, and provides evidence for a number of risk and protective factors for the development of oral leukoplakia; however, the definitive mechanisms for the occurrence and development of oral leukoplakia still remain to be elucidated, and further studies on these relevant mechanisms are still needed.

BACKGROUND: The role of microbes in diseases, especially cancer, has garnered significant attention. However, research on the oral microbiota in oral potentially malignant disorders (OPMDs) remains limited. Our study investigates microbial communities in OPMDs.
METHODS: Oral biopsies from19 oral leukoplakia (OLK) patients, 19 proliferative verrucous leukoplakia (PVL) patients, 19 oral lichen planus (OLP) patients, and 19 oral lichenoid lesions (OLL) patients were obtained. 15 SCC specimens were also collected from PVL patients. Healthy individuals served as controls, and DNA was extracted from their paraffin-embedded tissues. 2bRAD-M sequencing generated taxonomic profiles. Alpha and beta diversity analyses, along with Linear Discriminant Analysis effect size analysis, were conducted.
RESULTS: Our results showed the microbial richness and diversity were significantly different among groups, with PVL-SCC resembling controls, while OLK exhibited the highest richness. Each disease group displayed unique microbial compositions, with distinct dominant bacterial species. Noteworthy alterations during PVL-SCC progression included a decline in Fusobacterium periodonticum and an elevation in Prevotella oris.
CONCLUSIONS: Different disease groups exhibited distinct dominant bacterial species and microbial compositions. These findings offer promise in elucidating the underlying mechanisms of this disease.

OBJECTIVE: Chemoprevention can be a treatment for potentially malignant lesions (PMLs). We aimed to evaluate whether artemisinin (ART) and cisplatin (CSP) are associated with apoptosis and immunogenic cell death (ICD) in vitro, using oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) cell lines, and whether these compounds prevent OL progression in vivo.
METHODS: Normal keratinocytes (HaCat), Dysplastic oral cells (DOK), and oral squamous cell carcinoma (SCC-180) cell lines were treated with ART, CSP, and ART + CSP to analyze cytotoxicity, genotoxicity, cell migration, and increased expression of proteins related to apoptosis and ICD. Additionally, 41 mice were induced with OL using 4NQO, treated with ART and CSP, and their tongues were histologically analyzed.
RESULTS: In vitro, CSP and CSP + ART showed dose-dependent cytotoxicity and reduced SCC-180 migration. No treatment was genotoxic, and none induced expression of proteins related to apoptosis and ICD; CSP considerably reduced High-mobility group box-1 (HMGB-1) protein expression in SCC-180. In vivo, there was a delay in OL progression with ART and CSP treatment; however, by the 16th week, only CSP prevented progression to OSCC.
CONCLUSIONS: Expression of proteins related to ICD and apoptosis did not increase with treatments, and CSP was shown to reduce immunogenic pathways in SCC-180, while reducing cell migration. ART did not prevent the malignant progression of OL in vivo; CSP did despite significant adverse effects.

Stress and anxiety may be found in patients with oral submucous fibrosis (OSMF), oral leukoplakia (OL) and oral lichen planus (OLP). Cortisol, sometimes referred to as the \"stress hormone,\" has been employed as a stress predictor. Therefore, it is of interest to estimate the levels of depression, anxiety and serum cortisol and establish correlation between them in patients with OL. OLP and OSMF. There were 240 patients, aged 20 years to 45 years, who were divided into four categories (OL, OSMF, OLP and control) of 60 patients apiece. In the supervision of a psychiatrist, the Hamilton Depression Rating Scale (HAM D) and Hamilton Anxiety Rating Scale (HAM (A) questionnaires were filled out. Five millilitres of venous blood were extracted using standard aseptic technique, and all of the samples were examined for serum cortisol level. Anxiety and depression was found in subjects of OL, OSMF and OLP at advanced stages. It was inferred that serum cortisol level was statistically correlated with depression and anxiety in patients with OL, OSMF and OLP.

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.

Introduction Potentially malignant disorders, like oral lichen planus (OLP) and oral leukoplakia (OL) of several degrees of dysplasia, manifest a significant potential of malignant transformation being a precursor of oral squamous cell carcinoma (OSCC). The role of microvascularization in carcinogenesis is critical; therefore, microvascularization constitutes a major therapeutic target. DAPK-1 constitutes a possible cancer marker, with proven implications in other human cancers, and there isn\'t any study on its vascular endothelial expression in the oral cavity, particularly in oral cancer and oral potentially malignant diseases. The present study aims to investigate the vascular endothelial expression of the DAPK-1 in paraffin-embedded tissue samples of oral leukoplakia, oral squamous cell carcinoma, and oral lichen planus. Materials and methods The study focuses on the immunohistochemical, vascular-endothelial, expression pattern of biomarker DAPK-1 (NBP2-38468, Novus Biologicals, Centennial, CO, US). Tissue samples were obtained from six cases of oral lichen planus (OLP) (3 of reticular and 3 of erosive form), 30 cases of oral leukoplakia (OL) (10 with no dysplasia, 10 with mild dysplasia, and 10 with moderate/severe dysplasia), 22 cases of OSCC (2 well-differentiated, 17 moderately differentiated, and 3 poorly differentiated), as well as 5 cases of normal oral epithelium. The tissue samples were retrieved from the archives of the Department of Oral Medicine/Pathology, School of Dentistry, Aristotle University of Thessaloniki, as well as from St Lukas Hospital of Thessaloniki, Greece, from 2004-2019. In accordance with the Research and Ethics Committee guidelines of the Aristotle University, School of Dentistry, and the Helsinki II declaration, the study was conducted. The primary inclusion criteria for the study focused on the presence of sufficient precancerous or cancerous tissue. Conversely, inadequate tissue served as the exclusion criteria. The staining was evaluated exclusively in a quantitative manner. The vascular endothelial staining was evaluated as either positive or negative. If at least one endothelial cell exhibited positive staining, the section was classified as positive. Statistical analysis was carried out using SPSS Statistics v25.0 (IBM Corp., Armonk, NY, US) utilizing Pearson\'s chi-square or Fisher\'s exact test, depending on the sample size, to compare OLP to OL, OLP to OSCC, OLP to normal, OL to OSCC, OL to normal, and OSCC to normal. The significance level was established at 0.05 (p=0.05). Results A prevalence of positive OL cases may be noticed. The comparison between OLP and OL yielded Fisher\'s exact test of p>0.999, OLP and OSCC p=0.389, OLP and normal oral epithelium p>0.999, OL and OSCC p=0.226, OL and normal oral epithelium p>0.999, as well as OSCC and normal oral epithelium p=0.342. Conclusions The role of DAPK in tumorigenesis is already supported by limited literature. However, its implication in the development of OSCC and oral potentially malignant disorders (OPMDs) has yet to be elucidated. Its elevated expression in OL suggests a role in affecting the microenvironment, the vessels, in particular, surrounding oral potentially malignant lesions, possibly assisting their transition into cancer. The evaluation of the vascular-endothelial immunohistochemical profile of DAPK-1 in OL, OLP, and OSCC requires further studies in more tissue samples to illustrate its possible implications.

UNASSIGNED: The progression and pathogenesis of oral cancer is greatly impacted by epigenetic modifications, such as DNA methylation. Autophagy, is an adaptive mechanism used to maintain the survival and integrity of cells. Oral squamous cell carcinoma is linked to a number of autophagy indicators, although it is yet unknown if DNA methylation of autophagy-related genes promotes the development of oral leukoplakia (OL), oral squamous cell carcinoma (OSCC).
UNASSIGNED: Our study was aimed to assess, compare and evaluate the DNA methylation of ATG5 and MAP1LC3Av1 genes in oral leukoplakia, oral squamous cell carcinoma.
UNASSIGNED: This cross-sectional study was designed with sample size of 48 tissues which was clinically and histopathologically diagnosed as OL, OSCC and normal tissue. The samples were divided into three groups (Group A, Group B, and Group C; (n = 16 each). Following histopathological confirmation, the tissue was stored in the RNA reagent, then subjected to DNA extraction, methylation-sensitive polymerase chain reaction (MS-PCR). DNA methylation of the ATG5 and MAP1LC3Av1 genes were assessed.
UNASSIGNED: Shapiro-Wilk and Kolmogorov-Smirnov tests showed that the values were normally distributed. Both the ATG5 and MAP1LC3Av1 genes were methylated in OSCC, OL tissues compared to normal tissues. A statistically significant results was seen among the three study groups.
UNASSIGNED: A significant difference was noted in the hypermethylation status of the promoter regions of the ATG5 and MAP1LC3Av1 genes. This provides some insight into their crucial role in the development of tumors. Future research with larger sample is needed to assess its potential clinical implications in oral carcinoma.

BACKGROUND: Radiotherapy (RT) has numerous effects on the oral mucosa, primarily genetic alterations and changes in the microenvironment. The characteristics of oral leukoplakia (OL) may differ between patients who have received previous head and neck cancer (HNC) treatment with radiation therapy and those who have not. Due to a lack of data on this scenario, we aimed to investigate the surgical outcomes of OL by comparing these two patient groups.
METHODS: This retrospective cohort study enrolled a total of 224 OL lesions in 124 patients who underwent carbon dioxide laser (CO2 laser) surgery from July 2002 to Aug 2021. All patients had received previous treatments for HNC, with 59 patients undergoing only surgical approach, 65 patients undergoing RT, and 46 patients undergoing concurrent chemotherapy during RT. The analysis was performed on a per-lesion basis, not a per-capita basis. We investigated the associations of clinicopathological characteristics and treatment outcomes of OL lesions that developed from irradiated or nonirradiated oral mucosa.
RESULTS: The median follow-up time was 5.87 years. Postoperative recurrence of OL occurred in 30 patients. Malignant transformation occurred in 17 patients with the incidence rate 4.19% annually and 13.7% cumulatively. The average time for OL transforming into squamous cell carcinoma was 3.27 ± 3.26 years (median 1.82, range 0.11 - 11.90). In univariate analysis, non-homogeneous morphology (P = 0.042), moderate to high-grade dysplasia (P = 0.041), and nonirradiated oral mucosa (P = 0.0047) were predictors for malignant transformation. However, in the Cox proportional hazard model, only nonirradiated oral mucosa remained an independent prognostic factor related to postoperative malignant transformation of OL (P = 0.031, HR 5.08, CI95 1.16 - 22.25).
CONCLUSIONS: In the population whose OL is strongly aetiologically linked to environmental carcinogens such as betel nut and tobacco, OL lesions that develop on previously irradiated oral mucosa have a lower risk for postoperative malignant transformation compared to those that develop on nonirradiated mucosa. This finding highlights the potential impacts of radiation on OL. Further research is needed to confirm this observation and elucidate the underlying mechanism.

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