Evaluation of ABCB5 immunostained epithelial stem cells in oral squamous cell carcinoma, inflammatory gingival hyperplasia and normal mucosa

Oral cancer is the most prevalent head and neck cancer. Although tumor markers have been investigated for detecting the progression and prognosis of oral cancer, no reliable marker has been identified. We investigated the expression of ATP binding cassette subfamily B member 5 (ABCB5) positive stem cells in oral squamous cell carcinoma (OSCC) and in inflammatory gingival hyperplasia. We used tissue samples from normal subjects, patients with inflammatory gingival hyperplasia, and patients with OSCC. Samples were investigated using anti-ABCB5 monoclonal antibody immunohistochemistry to detect epithelial stem cells. Staining density, intensity, and immunoreactive scores of ABCB5 were analyzed for the three study groups. We found ABCB5 immunostaining in all three study groups, but different distributions of ABCB5 expression in different layers of the epithelium. We found no significant difference in staining intensity between inflammatory hyperplasia and normal mucosa, but we found significantly stronger expression in OSCC compared to normal and inflammatory hyperplasia individually. Elevated expression of ABCB5 in OSCC suggests an increased subpopulation of tumor cells with an undifferentiated stem cell phenotype, which facilitates cancer initiation and progression.

Comparison of the prognostic value of lymph node yield, lymph node ratio, and number of lymph node metastases in patients with oral squamous cell carcinoma

BACKGROUND

The aim of this study was to assess the prognostic significance of lymph node yield (LNY), lymph node ratio (LNR), and the number of lymph node metastases (LNMs) in patients affected by oral squamous cell carcinoma (OSCC).

METHODS

The study included patients who underwent surgical treatment for primary OSCC. Receiver operating characteristic curves were generated to determine the optimal threshold values. Kaplan-Meier curves were employed, along with the log-rank test, for the analysis of survival. To compare the performance in terms of model fit, we computed Akaike's information criterion (AIC).

RESULTS

This study enrolled 429 patients. Prognostic thresholds were determined at 22 for LNY, 6.6% for LNR, and 3 for the number of LNMs. The log-rank test revealed a significant improvement in both overall survival and progression-free survival for patients with a LNR of ≤6.6% or a number of LNMs of ≤3 (p < 0.05). Interestingly, LNY did not demonstrate prognostic significance. The AIC analyses indicated that the number of LNMs is a superior prognostic indicator compared to LNY and LNR.

CONCLUSIONS

Incorporating LNR or the number of LNMs into the TNM classification has the potential to improve the prognostic value, as in other types of cancers. Particularly, the inclusion of the number of LNMs should be contemplated for future N staging.

Prognostic Significance of Regional Disease in Young Patients with Oral Cancer: A Comparative Study

BACKGROUND

Regional metastases are considered the most important prognostic factor in OSCC patients. We aimed to investigate the impact of regional disease among different age groups with OSCC.

METHODS

A retrospective comparison between patients 40 years old or younger, 41-69 years old, and 70 years or older treated for OSCC between 2000 and 2020 in a tertiary-care center.

RESULTS

279 patients were included. The mean age was 65 ± 17.7 and 133 were male (47.7%). Thirty-six (12.9%) were 40 years old or younger, 101 (36.2%) were 41-69 years and 142 (50.9%) were 70 years or older. Five-year overall survival and disease-specific survival (DSS) were significantly better among patients younger than 40 compared to the mid-age group and patients 70 years or older (76.7% vs. 69.4% vs.48.2%, Log-rank p < 0.001, and 76.7% vs. 75.3% vs. 46.5%, Log-rank p < 0.001, respectively). While an association between regional spread and overall survival and DSS was demonstrated among all age groups, the odds ratio (OR) for death of any cause and death of disease regarding cervical metastasis was much higher among patients younger than 40 compared with the 41-69 and 70+ age groups (death of any cause-OR = 23, p-value = 0.008, OR = 2.6, p-value = 0.026, OR = 2.4, p-value = 0.13, respectively. Death of disease-OR = 23, p-value = 0.008, OR = 2.3, p-value = 0.082, OR = 4.1, p-value = 0.001, respectively). In univariate  analysis, regional metastasis was associated with disease-free survival only among patients younger than 40 (p-value = 0.04).

CONCLUSIONS

Regional metastases correspond with worse prognosis in young patients compared to older patients. These patients may benefit from a comprehensive treatment approach with close post-treatment follow-up.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:2212-2220, 2024.

Development of a novel senescence-related gene signature to predict clinical outcomes, immune landscape, and chemotherapeutic sensitivity in oral squamous cell carcinoma

BACKGROUND

Cellular senescence significantly associates with tumor initiation, progression, and therapeutic response across multiple cancers. Here, we sought to develop a novel senescence-related genes (SRGs)-derived signature for oral squamous cell carcinoma (OSCC) prognostication and therapeutic response prediction.

METHODS

OSCC-specific SRG prognostic signature was established with univariate Cox regression, Kaplan-Meier survival, and LASSO-penalized multivariate Cox regression analyses. A SRG nomogram integrating this signature and selected clinicopathological parameters were constructed by multivariate Cox regression. SiRNA-mediated gene knockdown was exploited to validate its function in vitro. The utilities of SRG signature in predicting immune status and chemotherapeutic sensitivities were analyzed.

RESULTS

The prognostic performance of SRG signature/nomogram was satisfactory in multiple independent cohorts. CDK1 knockdown induced senescence phenotype in vitro. Moreover, SRG signature scores negatively correlated with tumor-infiltrating immune cells and associated with multiple chemotherapeutic drug sensitivities.

CONCLUSIONS

Our results established SRG-derived signature/nomogram as powerful predictors for prognosis and chemotherapeutic response for OSCC.

Malignancy around implants in patients with a history of a potentially malignant or malignant lesion: a systematic review

The majority of problematic conditions resulting from dental implant treatment are inflammatory in character, but certain isolated occurrences of primary oral squamous cell carcinoma (OSCC) have been discovered in the area of implants. The goal of this study was to examine whether there is a link between dental implants and the development of OSCC in patients who have a history of a potentially malignant lesion (PML) or malignancy. Using the keywords "carcinoma" AND "dental implants," a search was conducted in the MEDLINE (PubMed), National Center for Biotechnology Information, and Google Scholar databases for case reports and case series in which OSCC was discovered as a primary cancer in the region of dental implants. An initial search identified 260 articles, 247 of which were excluded based on study inclusion or exclusion criteria, leaving 13 articles chosen for inclusion and a total of 30 patients who developed primary oral cancer surrounding osseointegrated titanium-based dental implants. In the studies included in the present review, 22 (73%) of 30 patients with peri-implant cancer had a history of PML or carcinoma. There is no statistical evidence of a direct association between dental implants and OSCC in patients with a history of a PML or malignant lesion. There have been some case reports of OSCC in the region of dental implants in patients with a history of a PML or malignant lesion, but further studies are needed to prove a definitive relationship.

Basal differentiation and expression status of SOX2 and KLF4 in basal layers are prognostic factors for disease-specific survival in oral squamous cell carcinoma

BACKGROUND

Basal differentiation in oral squamous cell carcinoma is usually detected at invasive sites. However, its significance as a prognostic value has been poorly investigated.

METHODS

COL17 was selected as a basal differentiation marker because of its stable expression in the basal-like cells of oral squamous cell carcinoma. Sixty-five cases of oral squamous cell carcinoma were subclassified into COL17-high (30 cases) and -low (35 cases) types, and the prognostic value was analyzed by Cox regression analysis. In addition, the stem cell markers such as SOX2, KLF4, MYC as well as the stem cell-related markers BMI1, EZH2, and YAP and its paralog TAZ, were immunohistochemically analyzed. Their prognostic values were investigated along with their COL17 status by Cox regression analysis.

RESULTS

No significant difference was observed between the COL17-high and -low groups in the disease-specific survival and recurrence-free survival in oral squamous cell carcinoma. When the COL17-high and -low categories were combined with the SOX2, KLF4, EZH2, or YAP/TAZ status in the basal layers, together with gender and age as covariates, the hazard ratios reached 3.3, 3.7, 2.8, and 3.1, respectively. In addition, multivariate analysis, including COL17, SOX2, and KLF4, with gender and age as covariates, showed a significantly poor prognosis for disease-specific survival.

CONCLUSION

Based on the relatively high hazard ratios, it is indicated that basal differentiation and the expression status of SOX2 and KLF4 in the basal layers are prognostic factors for oral squamous cell carcinoma.

CDK1 and CCNA2 play important roles in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a malignant tumor that occurs in oral cavity and is dominated by squamous cells. The relationship between CDK1, CCNA2, and OSCC is still unclear. The OSCC datasets GSE74530 and GSE85195 configuration files were downloaded from the Gene Expression Omnibus (GEO) database and were derived from platforms GPL570 and GPL6480. Differentially expressed genes (DEGs) were screened. The weighted gene co-expression network analysis, functional enrichment analysis, gene set enrichment analysis, construction and analysis of protein-protein interaction (PPI) network, Comparative Toxicogenomics Database analysis were performed. Gene expression heatmap was drawn. TargetScan was used to screen miRNAs that regulate central DEGs. A total of 1756 DEGs were identified. According to Gene Ontology (GO) analysis, they were predominantly enriched in processes related to organic acid catabolic metabolism, centromeric, and chromosomal region condensation, and oxidoreductase activity. In Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, the DEGs were mainly concentrated in metabolic pathways, P53 signaling pathway, and PPAR signaling pathway. Weighted gene co-expression network analysis was performed with a soft-thresholding power set at 9, leading to the identification of 6 core genes (BUB1B, CCNB1, KIF20A, CCNA2, CDCA8, CDK1). The gene expression heatmap revealed that core genes (CDK1, CCNA2) were highly expressed in OSCC samples. Comparative Toxicogenomics Database analysis demonstrated associations between the 6 genes (BUB1B, CCNB1, KIF20A, CCNA2, CDCA8, CDK1) and oral tumors, precancerous lesions, inflammation, immune system disorders, and tongue tumors. The associated miRNAs for CDK1 gene were hsa-miR-203a-3p.2, while for CCNA2 gene, they were hsa-miR-6766-3p, hsa-miR-4782-3p, and hsa-miR-219a-5p. CDK1 and CCNA2 are highly expressed in OSCC. The higher the expression of CDK1 and CCNA2, the worse the prognosis.

Lipid droplets' functional protein caveolin-2 is associated with lipid metabolism-related molecule FABP5 and EMT marker E-cadherin in oral epithelial dysplasia

AIMS

To explore the accumulation of lipid droplets (LDs) and its relationship with lipid metabolism, and epithelial-mesenchymal transition (EMT) in the carcinogenesis processes in the oral cavity.

METHODS

LDs were stained by oil red O. Forty-eight oral squamous cell carcinomas (OSCC), 78 oral potentially malignant disorders (OPMDs) and 25 normal tissue sections were included to explore the LDs surface protein caveolin-2 and perilipin-3, lipid metabolism-related molecule FABP5 and EMT biomarker E-cadherin expression by immunohistochemical staining.

RESULTS

The accumulation of LDs was observed in OPMDs and OSCCs compared with normal tissues (p<0.05). In general, an increasing trend of caveolin-2, perilipin-3 and FABP5 expression was detected from the normal to OPMDs to OSCC groups (p<0.05). Additionally, caveolin-2, perilipin-3 and FABP5 expression were positively correlated with epithelial dysplasia in OPMDs, whereas E-cadherin positivity was negatively correlated with histopathological grade in both OPMDs and OSCC, respectively. A negative correlation of caveolin-2 (p<0.01, r =-0.1739), and FABP5 (p<0.01, r =-0.1880) with E-cadherin expression was detected. The caveolin-2 (p<0.0001, r=0.2641) and perilipin-3 (p<0.05, r=0.1408) staining was positively correlated with FABP5. Increased caveolin-2 expression was related to local recurrence and worse disease-free survival (p<0.05).

CONCLUSION

In the oral epithelial carcinogenesis process, LDs begin to accumulate early in the precancerous stage. LDs may be the regulator of FABP5-associated lipid metabolism and may closely related to the process of EMT; caveolin-2 could be the main functional protein.

Tra2β exerts tumor-promoting effects via GSK3/β-catenin signaling in oral squamous cell carcinoma

OBJECTIVES

The splicing factor transformer-2 homolog beta (Tra2β) plays a pivotal role in various cancers. Nonetheless, its role in oral squamous cell carcinoma (OSCC) has not been comprehensively explored. This study sought to discern the influence of Tra2β on OSCC and its underlying mechanisms.

MATERIALS AND METHODS

We assessed Tra2β expression in OSCC utilizing immunohistochemistry, qRT-PCR, and western blotting techniques. siRNA transfection was used to silence Tra2β. Whole transcriptome RNA sequencing (RNA-seq) analysis was carried out to reveal the alternative splicing (AS) events. KEGG pathway analysis enriched the related pathways. Colony formation, transwell, wound healing, and Annexin V-FITC/PI were employed to appraise the consequences of Tra2β silencing on OSCC.

RESULTS

Tra2β was highly expressed in both OSCC tissues and cell lines. Knockdown of Tra2β-regulated AS events with skipped exon (SE) accounts for the highest proportion. Meanwhile, downregulation of Tra2β reduced cell proliferation, migration, and invasion, however increasing cell apoptosis. Moreover, Wnt signaling pathway involved in the function of Tra2β knockdown which was demonstrated directly by a discernible reduction in the expression of GSK3/β-catenin signaling axis.

CONCLUSIONS

These findings suggest that knockdown of Tra2β may exert anti-tumor effects through the GSK3/β-catenin signaling pathway in OSCC.

Knockdown of circXPO1 inhibits the development of oral squamous cell carcinoma cells

BACKGROUND

Circular RNAs (circRNAs) have emerged as pivotal regulators of cellular processes in human malignancies, including oral squamous cell carcinoma (OSCC).

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect RNA expression levels of circXPO1, miR-524-5p and cyclin D1 (CCND1). Colony formation assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay were performed to analyze cell proliferation, while transwell assay was carried out to investigate the cell migration and invasion. Cell apoptosis was assessed by flow cytometry. Protein expression analysis was implemented by Western blot assay. Additionally, lactate production and glucose consumption were investigated using a lactate assay kit and glucose assay kit, respectively. The in vivo tumorigenic potential of circXPO1 was evaluated using a xenograft mouse model assay.

RESULTS

Elevated levels of circXPO1 and CCND1, alongside reduced miR-524-5p expression were decreased in OSCC tissues and cells. Knockdown of circXPO1 in OSCC cells inhibited their proliferative, migratory and invasive capacities, as well as glycolysis, prompting apoptosis. Moreover, circXPO1 silencing hindered tumor growth in vivo. MiR-524-5p could be sequestered by circXPO1, and its inhibition could counteract the beneficial effects of circXPO1 knockdown on OSCC progression.

CONCLUSION

Knockdown of circXPO1 inhibited OSCC progression by up-regulating miR-524-5p and down-regulating CCND1 expression, which might provide potential targets for OSCC treatment.

Application of Natural Medicinal Plants Active Ingredients in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant cancer of the head and neck, with high morbidity and mortality, ranking as the sixth most common cancer in the world. The treatment of OSCC is mainly radiotherapy, chemotherapy and surgery, however, the prognosis of patients is still poor and the recurrence rate is high. This paper reviews the range of effects of natural medicinal plant active ingredients (NMPAIs) on OSCC cancer, including the types of NMPAIs, anti-cancer mechanisms, involved signaling pathways, and clinical trials. The NMPAIs include terpenoids, phenols, flavonoids, glycosides, alkaloids, coumarins, and volatile oils. These active ingredients inhibit proliferation, induce apoptosis and autophagy, inhibit migration and invasion of OSCC cells, and regulate cancer immunity to exert anti-cancer effects. The mechanism involves signaling pathways such as mitogen-activated protein kinase, phosphatidylinositol 3 kinase/protein kinase B, nuclear factor kappa B, miR-22/WNT1/β-catenin and Nrf2/Keap1. Clinically, NMPAIs can inhibit the growth of OSCC, and the combined drug is more effective. Natural medicinal plants are promising candidates for the treatment of OSCC.

Advances in Small Molecular Agents against Oral Cancer

Oral cancer is a common malignancy with a high mortality rate. Although surgery is the best treatment option for patients with cancer, this approach is ineffective for advanced metastases. Molecular agents are irreplaceable in preventing and treating distant metastases. This review aims to summarise the molecular agents used for the treatment of oral cancer in the last decade and describe their sources and curative effects. These agents are classified into phenols, isothiocyanates, anthraquinones, statins, flavonoids, terpenoids, and steroids. The mechanisms of action of these agents include regulating the expression of cell signalling pathways and related proteases to affect the proliferation, autophagy, migration, apoptosis, and other biological aspects of oral cancer cells. This paper may serve as a reference for subsequent studies on the treatment of oral cancer.

Impact of preoperative haemoglobin, albumin, lymphocyte, and platelet score on oral cancer prognosis

OBJECTIVE

To evaluate the preoperative haemoglobin, albumin, lymphocyte, and platelet score as a prognostic indicator in oral squamous cell carcinoma treated by radical surgery.

SUBJECTS AND METHODS

Patients (83 men, 32 women; 65.80 ± 11.47 years) who underwent radical surgery between 2012 and 2022 were included. Factors affecting overall survival and disease-free survival according to the haemoglobin, albumin, lymphocyte, and platelet score were examined. Patients were categorised into low- and high-score groups using optimal cut-off values obtained from receiver operating characteristic curve analysis.

RESULTS

The low-score group had poorer overall and disease-free survival (p < 0.001 each). Multivariate analysis identified alcohol consumption (hazard ratio [HR], 3.83; 95% confidence interval [CI]: 1.56-9.41, p = 0.003); vascular invasion (HR, 3.97; 95% CI: 1.60-9.85, p = 0.003); and the haemoglobin, albumin, lymphocyte, and platelet score (HR, 0.39; 95% CI: 0.20-0.78, p = 0.007) as independent prognostic factors for overall survival and vascular (HR, 3.66; 95% CI: 1.79-7.50, p < 0.001) and lymphovascular (HR, 2.44; 95% CI: 1.36-4.41, p = 0.003) invasion as independent prognostic factors for disease-free survival.

CONCLUSION

The preoperative haemoglobin, albumin, lymphocyte, and platelet score may be a significant prognostic factor for patients with oral squamous cell carcinoma undergoing radical surgery.

Downregulation of salivary miR-3928 as a potential biomarker in patients with oral squamous cell carcinoma and oral lichen planus

OBJECTIVES

Recent studies highlighted the role of miR expressed in saliva as reliable diagnostic and prognostic tools in the long-term monitoring of cancer processes such as oral squamous carcinoma (OSCC). Based on a few previous studies, it seems the miR-3928 can be considered a master regulator in carcinogenesis, and it can be therapeutically exploited. This is the first study that compared oral potentially malignant disorder (OLP) and malignant (OSCC) lesions for miR-3928 expression.

MATERIALS AND METHODS

In this cross-sectional study, saliva samples from 30 healthy control individuals, 30 patients with erosive/atrophic oral lichen planus, and 31 patients with OSCC were collected. The evaluation of miR-3928 expression by q-PCR and its correlation with clinicopathological indices were analyzed by Shapiro-Wilk, Kruskal-Wallis, Pearson's χ2 , and Mann-Whitney tests. The p-value less than .05 indicated statistically significant results.

RESULTS

Based on nonparametric Kruskal-Wallis test results, there was a statistically significant difference between the ages of three study groups (p < .05). This test demonstrated a statistically significant difference between the average of miR-3928 expression in three study groups (p < .05). The result of the χ2  test showed a statistically significant difference in miR-3928 expression between patients with OLP (p = .01) and also patients with OSCC (p < .0001) in comparison to the control group.

CONCLUSIONS

The salivary miR-3928 can play a tumor suppressive role in the pathobiology of OSCC, and it is significantly downregulated in patients. According to the potential tumor suppressive role of miR-3928 in the OSCC process, we can consider this microRNA as a biomarker for future early diagnosis, screening, and potential target therapy.

Evodiamine inhibits EPRS expression to regulate glutamate metabolism and proliferation of oral squamous cell carcinoma cells

The effects of evodiamine (EVO) on oral squamous cell carcinoma (OSCC) are not yet understood. Based on our earlier findings, we hypothesized that evodiamine may affect OSCC cell proliferation and glutamate metabolism by modulating the expression of EPRS (glutamyl-prolyl-tRNA synthetase 1). From GEPIA, we obtained EPRS expression data in patients with OSCC as well as survival prognosis data. An animal model using Cal27 cells in BALB/c nude mice was established. The expression of EPRS was assessed by immunofluorescence, Western blotting, and quantitative PCR. Glutamate measurements were performed to evaluate the impact of evodiamine on glutamate metabolism of Cal27 and SAS tumor cells. transient transfection techniques were used to knock down and modulate EPRS in these cells. EPRS is expressed at higher levels in OSCC than in normal tissues, and it predicts poor prognosis in patients. In a nude mouse xenograft model, evodiamine inhibited tumor growth and the expression of EPRS. Evodiamine impacted cell proliferation, glutamine metabolism, and EPRS expression on Cal27 and SAS cell lines. In EPRS knockdown cell lines, both cell proliferation and glutamine metabolism are suppressed. EPRS's overexpression partially restores evodiamine's inhibitory effects on cell proliferation and glutamine metabolism. This study provides crucial experimental evidence supporting the potential therapeutic application of evodiamine in treating OSCC. Evodiamine exhibits promising anti-tumor effects by targeting EPRS to regulate glutamate metabolism.

Inhibin A contributes to the tumorigenesis of oral squamous cell carcinoma by KIAA1429-mediated m6A modification

BACKGROUND

Inhibin A and N6-methyladenosine methylation modifications participate in oral squamous cell carcinoma development. However, the N6-methyladenosine modification of Inhibin A in oral squamous cell carcinoma has not been revealed. This study reveals a key gene "Inhibin A" that may affect the tumorigenesis of oral squamous cell carcinoma and its molecular mechanisms on N6-methyladenosine methyltransferase KIAA1429-mediated N6-methyladenosine methylation modification.

METHODS

Bioinformatics analysis and quantitative real-time polymerase chain reaction identified the potential regulatory genes in oral squamous cell carcinoma. We examined the changes in the proliferation (Cell Counting Kit-8 assay), migration (transwell migration assay), and invasion (transwell invasion assays) of oral squamous cell carcinoma cells. We performed a xenograft tumor experiment to validate the role of Inhibin A in oral squamous cell carcinoma in vivo. The interactions between Inhibin A and KIAA1429 were analyzed using bioinformatics, methylated RNA immunoprecipitation-qPCR, quantitative real-time polymerase chain reaction, and Western blotting experiments.

RESULTS

Inhibin A had the highest expression in patients with oral squamous cell carcinoma. Inhibin A silencing impaired the ability of oral squamous cell carcinoma cells to proliferate, migrate, and invade, as well as limited the tumorous growth of oral squamous cell carcinoma cells in vivo. Bioinformatics analysis showed that Inhibin A expression positively interacted with KIAA1429 expression in The Cancer Genome Atlas database. The levels were also upregulated in our clinical samples. Furthermore, KIAA1429 silencing repressed the N6-methyladenosine level of Inhibin A in oral squamous cell carcinoma.

CONCLUSIONS

Inhibin A promotes the tumorigenesis of oral squamous cell carcinoma by KIAA1429-mediated N6-methyladenosine modification. This study adds to our current knowledge of the molecular mechanisms underlying oral squamous cell carcinoma malignancy.

Paradigm Change for Intraoperative Surgical Margin Assessment for Oral Squamous Cell Carcinoma

OBJECTIVE

Achieving clear surgical margins is one of the primary surgical goals in treating oral squamous cell carcinoma (OSCC) and thus aiming to improve overall and disease-specific survival. Therefore, we developed the Goal-Oriented Assessment for Intraoperative Margin ('GAIM') protocol, a novel intraoperative approach for margin assessment, and present here our 5-year experience and outcomes.

METHODS

'GAIM' is a 7-step procedure comprising systematic ruler-aided resection of labeled tumor-bed margins, frozen section (FS) co-produced by both pathologists and operating surgeons, and immediate extension of resection according to FS findings. Data from all patients operated using the 'GAIM' protocol at a single tertiary center between 2018 to 2022 were analyzed, including margin status on FS and final pathology (FP) records, recurrence, and mortality.

RESULTS

A total of 196 patients were included, 56.6% (n = 111) stages I-II, and 43.4% (n = 85) stages III-IV. Using the 'GAIM' protocol, we achieved an overall 94.4% of clean and revised clean surgical margins. Patients with a 2-year and longer follow-up (n = 141) had local recurrence in 3.5% when both FS and final margins were clean, 8.1% when FP margins were clean, and 16.7% with close/positive final margins.

CONCLUSIONS

The proposed 'GAIM' protocol is a novel, effective, reproducible, and safe approach for margin evaluation that can be systematically applied. It can increase the rate of final clean surgical margins and potentially improve patients' outcomes.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:1725-1732, 2024.

Cholesterol depletion induces mesenchymal properties in oral squamous cell carcinoma cell line

BACKGROUND

Cholesterol in cell membranes is crucial for cell signaling, adhesion, and migration. Membranes feature cholesterol-rich caveolae with caveolin proteins, playing roles in epithelial-mesenchymal transition and cancer progression. Despite elevated cholesterol levels in tumors, its precise function and the effects of its depletion in oral squamous cell carcinoma remain unclear. The aim of this study was to evaluate the influence of cholesterol depletion in oral squamous cell carcinoma cell line and epithelial-mesenchymal transition process.

METHODS

Cholesterol depletion was induced on SCC-9 cells by methyl-β-cyclodextrin and cell viability, proliferation, apoptosis, and colony formation capacities were evaluated. Gene and protein expressions were evaluated by reverse transcription polymerase chain reaction (RT-qPCR) and Western Blot, respectively, and cell sublocalization was assessed by immunofluorescence.

RESULTS

Cholesterol depletion resulted in alteration of oral squamous cell carcinoma cell morphology at different concentrations of methyl-β-cyclodextrin, as well as decreased cell proliferation and viability rates. Analysis of CAV1 transcript expression revealed increased gene expression in the treated SCC-9 during the 24 h period, at different concentrations of methyl-β-cyclodextrin: 5 , 7.5, 10, and 15 mM, in relation to parental SCC-9. CAV1 protein expression was increased, with subsequent dose-dependent decrease. A statistically significant difference was observed in samples treated with 5 mM of methyl-β-cyclodextrin (p = 0.02, Kruskal-Wallis test). The immunofluorescence assay showed lower cytoplasmic and membrane labeling intensity in the treated samples for CAV1.

CONCLUSION

These findings indicate the modulation of cholesterol as a possible mechanism underlying the regulation of these molecules and activation of epithelial-mesenchymal transition in oral squamous cell carcinoma.

Difference between Keratinized- and Non-Keratinized-Originating Epithelium in the Process of Immune Escape of Oral Squamous Cell Carcinoma

Immune checkpoint inhibitors (ICIs), including anti-programmed cell death 1 ligand 1 (PD-L1) antibodies, are significantly changing treatment strategies for human malignant diseases, including oral cancer. Cancer cells usually escape from the immune system and acquire proliferative capacity and invasive/metastatic potential. We have focused on the two immune checkpoints, PD-1/PD-L1 and CD47/SIRPα, in the tumor microenvironment of oral squamous cell carcinoma (OSCC), performed a retrospective analysis of the expression of seven immune-related factors (PD-L1, PD-1, CD4, CD8, CD47, CD56 and CD11c), and examined their correlation with clinicopathological status. As a result, there were no significant findings relating to seven immune-related factors and several clinicopathological statuses. However, the immune checkpoint-related factors (PD-1, PD-L1, CD47) were highly expressed in non-keratinized epithelium-originated tumors when compared to those in keratinized epithelium-originated tumors. It is of interest that immunoediting via immune checkpoint-related factors was facilitated in non-keratinized sites. Several researchers reported that the keratinization of oral mucosal epithelia affected the immune response, but our present finding is the first study to show a difference in tumor immunity in the originating epithelium of OSCC, keratinized or non-keratinized. Tumor immunity, an immune escape status of OSCC, might be different in the originating epithelium, keratinized or non-keratinized.

Macrophage-Capturing Self-Assembly Photosensitizer Nanoparticles Induces Immune Microenvironment Re-Programming and Golgi-Responsive Immunogenic Cell Death in Head and Neck Carcinoma

Head and neck carcinoma treatment is shifted toward the combination of therapy causing immune checkpoint blockade (ICB) and immunogenic cell death. In this study, a CSFRi-chimeric TAMCSFR+-targeting extracellular vesicle (EV@CSFRi) platform is developed and designed an intracellular protoporphyrin conjugated with RVRR peptide sequence for furin-cleavage to perform Golgi-targeting and generating ROS (GT-RG). The graphical abstract illustrates the self-assembly of GT-RG nanoparticles into nanofiber through the hydrophily of RVRR and hydrophobicity of RG, and the red line indicates the site of furin cleavage. As is shown in the Graphical abstract, the Golgi-targeting Protoporphyrin-RVRR platform is composed with CSFRi-chimeric extracellular vesicles and forms the tumor-responsive TAM-reprogramming bilayers (GT-RGEV@CSFRi). The GT-RGEV@CSFRi acted as a multifunctional theranostic platform, which can induce immunogenic cell death and further help modulate TAM, thus suppressing the HNC xenograft model by combination therapy with anti-PD-1.

The Neem Limonoid Nimbolide Modulates Key Components of the DNA Damage Response Signalling in Cellular and Animal Models of Oral Squamous Cell Carcinoma

BACKGROUND

Deregulated DNA damage response (DDR) network is implicated in cancer progression and therapy resistance.

OBJECTIVE

The present study was designed to investigate whether nimbolide, an anticancer neem limonoid, targets key components of the DDR signalling pathway in cellular and animal models of oral squamous cell carcinoma (OSCC).

METHODS

OSCC cells (SCC-4 and SCC-9), 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinoma model, chemoresistant OSCC patient-derived xenograft (PDX) model established in athymic nude mice, and tissue sections from patients with oral premalignant/malignant disease were used for the study. Key molecules that orchestrate the DDR, including the MRN complex, ATM, DNA-PKcs, H2AX, and p53, were analysed by qRT-PCR, immunoblotting, immunofluorescence, and immunohistochemistry. Cell proliferation and apoptosis indices were evaluated.

RESULTS

Nimbolide significantly reduced 8-oxodG levels, expression of MRN, ATMS1891, and γ-H2AX, with an increase in p-p53S15 in OSCC cells as well as in the HBP model. Nimbolide potentiated the effect of KU-55933 in ATM inhibition. In the PDX model, nimbolide suppressed tumor formation, stimulated DDR and apoptosis, inhibited cell proliferation, and enhanced sensitivity to cisplatin. Analysis of p-ATM expression revealed a significant increase during the sequential progression of hamster and human OSCC.

CONCLUSIONS

This study provides compelling evidence that nimbolide functions as a DDR inhibitor in cellular and hamster OSCC models and as a DDR activator in the PDX model primarily by targeting ATM. Small molecules like nimbolide that modulate DDR are of immense benefit in cancer therapy. The study has also unveiled p-ATM as a promising biomarker of tumour progression in human OSCCs.

Exosomes: A Cutting-Edge Theranostics Tool for Oral Cancer

Exosomes are a subpopulation of extracellular vesicles (EVs) secreted by cells. In cancer, they are key cellular messengers during cancer development and progression. Tumor-derived exosomes (TEXs) promote cancer progression. In oral cancer, the major complication is oral squamous cell carcinoma (OSCC). Exosomes show strong participation in several OSCC-related activities such as uncontrolled cell growth, immune suppression, angiogenesis, metastasis, and drug and therapeutic resistance. It is also a potential biomarker source for oral cancer. Some therapeutic exosome sources such as stem cells, plants (it is more effective compared to others), and engineered exosomes reduce oral cancer development. This therapeutic approach is effective because of its specificity, biocompatibility, and cell-free therapy (it reduced side effects in cancer treatment). This article highlights exosome-based theranostics signatures in oral cancer, clinical trials, challenges of exosome-based oral cancer research, and future improvements. In the future, exosomes may become an effective and affordable solution for oral cancer.

Enhanced lipid biosynthesis in oral squamous cell carcinoma cancer-associated fibroblasts contributes to tumor progression: Role of IL8/AKT/p-ACLY axis

Lipid metabolic reprogramming of tumor cells has been proven to play a critical role in tumor initiation and development. However, lipid metabolism in cancer-associated fibroblasts (CAFs) has rarely been studied, particularly in CAFs of oral squamous cell carcinoma (OSCC). Additionally, the molecular mechanism by which tumor cells regulate lipid metabolism in fibroblasts is unclear. In this study, we found that phosphorylated ATP citrate lyase (p-ACLY), a key lipid metabolic enzyme, was upregulated in OSCC CAFs. Compared to paracancerous normal fibroblasts, CAFs showed enhanced lipid synthesis, such as elevated cytosolic acetyl-CoA level and accumulation of lipid droplets. Conversely, reduction of p-ACLY level blocked this biological process. In addition, blocking lipid synthesis in CAFs or inhibiting fatty acid uptake by OSCC cells reduced the promotive effects of CAFs on OSCC cell proliferation, invasion, and migration. These findings suggested that CAFs are one of lipid sources required for OSCC progression. Mechanistically, AKT signaling activation was involved in the upregulation of p-ACLY level and lipid synthesis in CAFs. Interleukin-8 (IL8), an exocrine cytokine of OSCC cells, could activate AKT and then phosphorylate ACLY in fibroblasts. This study suggested that the IL8/AKT/p-ACLY axis could be considered as a potential target for OSCC treatment.

Higher overall survival rates of oral squamous cell carcinoma treated with metronomic neoadjuvant chemotherapy

Distant metastasis is an important prognostic factor for oral squamous cell carcinoma (OSCC). It involves the direct spread of tumor cells through blood vessels or via lymph nodes; however, there are currently no well-established treatments for its prevention in patients with OSCC. To investigate the impact of metronomic neoadjuvant chemotherapy on OSCC, we conducted a retrospective analysis of the efficacy of neoadjuvant chemotherapy with S-1 alone. Fifty-four patients underwent up-front surgery, while 106 received neoadjuvant chemotherapy with S-1 alone. A serious adverse event occurred in one of patient treated with neoadjuvant chemotherapy (1%); however, all patients underwent resection. The 5-year overall survival rate was higher with S-1 than with up-front surgery (96% vs. 81%, P = 0.002). Moreover, neoadjuvant chemotherapy significantly increased the overall survival rate of patients with poorly or moderately differentiated tumors, but not those with well-differentiated tumors. By analyzing a cohort of 523 head and neck squamous cell carcinoma (HNSCC) patients in the Cancer Genome Atlas, we identified genetic variants associated with histological differentiation. The frequency of pathogenic/likely pathogenic variants or deletions in 5 genes associated with HNSCC correlated with histological differentiation, some of which indicated the activation of the Wnt/β-catenin pathway in well-differentiated HNSCC. The vessel marker CD31 was highly expressed in poorly differentiated OSCC, whereas the anti-angiogenic molecule, LCN2, which is induced by the activation of the Wnt pathway, was highly expressed in well-differentiated OSCC. The present study showed that overall survival rates were higher in patients with poorly or moderately differentiated OSCC who received metronomic neoadjuvant chemotherapy, which was attributed to a difference in angiogenesis based on the characteristic landscape of pathogenic mutations according to histological differentiation.

Notch signaling genes and CD8+ T-cell dynamics: Their contribution to immune-checkpoint inhibitor therapy in oral squamous cell carcinoma: A retrospective study

BACKGROUND

Aberrant Notch signaling pathway has been related with the tumorigenesis in head and neck region, involving oral cavity. Here, we report the correlation between mutations in the Notch signaling pathway and CD8+ T-cell infiltration via PD-L1, which lead to enhanced antitumor immunity and may target for immune-checkpoint inhibitors (ICIs) therapy.

METHODS

This retrospective study analyzed the results of immunohistochemical staining for PD-L1 and CD8+ T-cell infiltration in 10 patients and whole-exome sequencing (WES) was conducted on five of these patients to identify frequently mutated genes.

RESULTS

Four of 10 patients were positive for PD-L1 and CD8+ T. By analyzing WES in three of these four patients, we notably identified the mutations of NOTCH1, FBXW7, and noncoding RNA intronic mutation in NOTCH2NLR in two of these three patients. This study may enable better selection of ICI therapy with CD8+ T-cell infiltration via PD-L1 expression for oral squamous cell carcinoma patients with mutations in Notch signaling pathway.

Circ-OMAC drives metastasis in oral squamous cell carcinoma

OBJECTIVES

Accumulating studies have proved that the circular RNAs (circRNAs) play vital roles in human cancers. However, few circRNAs have been elucidated with lymph node metastasis. This study demonstrated that circ-oral cancer metastasis-associated circRNA (circ-OMAC) is required to regulate the oral squamous cell carcinoma (OSCC) metastasis.

MATERIALS AND METHODS

The circ-OMAC were detected by circRNA-sequencing and further verified by in situ hybridization (ISH). The role of circ-OMAC was assessed by transwell assay and wound healing assay. Mechanistically, circ-OMAC regulated OSCC metastasis by initiating the epithelial-to-mesenchymal transition (EMT) signaling pathway.

RESULTS

Our findings suggested that circ-OMAC was aberrantly elevated in the metastatic lymph nodes as compared to primary OSCC tissues. OSCC patients with high levels of circ-OMAC were prone to a poor prognosis. By developing functional assays, we confirmed that circ-OMAC promotes metastasis of OSCC cells via initiation of EMT pathways.

CONCLUSIONS

We provide new insights whereby Circ-OMAC as an oncogene is a potential therapeutic target and prognostic marker in oral cancer.

FKBP4 correlates with CD8+ T cells and lymphatic metastases in oral squamous cell carcinoma

OBJECTIVES

To identify the engagement of CD8+ T cells in the lymph node metastasis (LNM) of oral squamous cell carcinoma (OSCC) and significant CD8+ T cell-related genes regulating the LNM.

SUBJECTS AND METHODS

Tumor samples of primary OSCC patients were obtained (n = 71). CD8 expression in LNM- and LNM+ tumors were identified using tissue microarray (TMA)-based immunohistochemistry (IHC) and compared using the Mann-Whitney U test. The LNM status, as well as the metagene expression of CD8+ T cells of OSCC patients, were obtained from The Cancer Genome Atlas (TCGA) database. Metagenes related to LNM were screened using logistic regression analyses and further identified using TMA-based IHC.

RESULTS

CD8 was significantly positively associated with LNM (p < 0.05). Furthermore, tumors with higher expression of FKBP4 had significantly higher LNM rate (HR: 1.63; 95% CI: 1.08 ~ 2.53; p < 0.05), which was also proven using TMA-based IHC analysis.

CONCLUSION

CD8+ T cells might engage in the lymphatic metastases of OSCC. Among CD8+ T cell-related genes, FKBP4 could be a promising biomarker to predict the risk of LNM of OSCC.

Artemisinin suppressed tumour growth and induced vascular normalisation in oral squamous cell carcinoma via inhibition of macrophage migration inhibitory factor

BACKGROUND

Tumour vascular normalisation therapy advocates a balance between pro-angiogenic factors and anti-angiogenic factors in tumours. Artemisinin (ART), which is derived from traditional Chinese medicine, has been shown to inhibit tumour growth; however, the relationship between ART and tumour vascular normalisation in oral squamous cell carcinoma (OSCC) has not been previously reported.

METHODS

Different concentrations(0 mg/kg, 25 mg/kg, 50 mg/kg, 100 mg/kg)of ART were used to treat the xenograft nude mice model of OSCC. The effects of ART on migration and proliferation of OSCC and human umbilical vein endothelial cells (HUVEC) cells were detected by scratch assay and CCK-8 assay. OSCC cells with macrophage migration inhibitory factor (MIF) silenced were constructed to explore the effect of MIF.

RESULTS

Treatment with ART inhibited the growth and angiogenesis of OSCC xenografts in nude mice and downregulated vascular endothelial growth factor (VEGF), IL-8, and MIF expression levels. ART reduced the proliferation, migration, and tube formation of HUVEC, as well as the expression of VEGFR1 and VEGFR2. When the dose of ART was 50 mg/kg, vascular normalisation of OSCC xenografts was induced. Moreover, VEGF and IL-8 were needed in rhMIF restoring tumour growth and inhibit vascular normalisation after the addition of rhMIF to ART-treated cells.

CONCLUSION

Artemisinin might induce vascular normalisation and inhibit tumour growth in OSCC through the MIF-signalling pathway.

Comparative analysis of trace elements in the saliva and serum of patients with oral submucous fibrosis and squamous cell carcinoma

Of note, one third of oral cancer or oral tissue dysfunction cases are from India, primarily resulting from the consumption of Gutkha, a type of smokeless tobacco prevalent among several Indian populations. Gutkha is a mixture of tobacco, areca nut, slaked lime, catechu, spices, sweeteners and essences. Oral submucous fibrosis (OSMF), which is linked to the consumption of areca nut products and tobacco, is a chronic, precancerous condition of the submucosal tissues. OSMF transforms into oral squamous cell carcinoma (OSCC) at a rate of 7-13%. Gutkha also contains various trace elements, such as copper (Cu), zinc (Zn), selenium (Se) and molybdenum (Mo). Alterations in trace element levels in the body are associated with cancer progression. The present study aimed to determine the levels of serum and salivary trace elements in patients with OSMF and OSCC. A total of 80 patients were selected for the study and were divided into four groups of 20 patients in each (Group A, gutkha intake without OSMF; group B, gutkha intake with OSMF; group C, OSCC; and group D, control). The level of Cu was found to be increased and the levels of Zn, Se and Mo were decreased in the serum of patients with OSMF and OSCC compared with the controls. The salivary levels of these elements were lower compared with those in the serum. Age and sex had no significant effect on the levels of these trace elements. The results of the present study affirm the fact that serum and salivary trace elements are altered in pre-malignant and malignant lesions as the disease progresses. As the composition of saliva often varies, monitoring serum trace element levels as diagnostic and prognostic markers may aid in the early detection of the disease and in the management of the treatment efficacy.

CD24 blockade promotes anti-tumor immunity in oral squamous cell carcinoma

OBJECTIVES

Our study elucidates the prognostic role of cluster of differentiation (CD) 24 expression in oral squamous cell carcinoma (OSCC) and determines whether targeting CD24 enhances the anti-tumor immune response by inhibiting tumor-associated macrophages (TAMs).

MATERIALS AND METHODS

The expression of CD24 and CD68 was analyzed immunohistochemically via tissue microarrays constructed using 56 cohorts of patients with OSCC and 20 control specimens. Further, CD24 was inhibited in an allograft squamous cell carcinoma (SCC) related mouse model with CD24mAb to determine the tumor volume and weight. Changes in immune cells such as TAMs and T cells in the tumor microenvironment (TME) were analyzed by Flow cytometry. The expression of CD4, CD8, and Ki67 was analyzed via immunohistochemistry. The inhibition of CD24 was confirmed by Western blot and immunohistochemistry.

RESULTS

CD24 was overexpressed in OSCC. High expression of CD24 indicated poor survival in patients with OSCC (p = 0.0334). CD24 expression was significantly correlated with CD68 (p = 0.0424). The inhibition of CD24 delayed tumor growth in vivo. A decrease in TAMs number and an increase in T cell number were confirmed, while the ability of tumor proliferation was impaired.

CONCLUSION

Targeting CD24 could enhance anti-tumor immune response by inhibiting TAMs.

Monoclonal antibody cetuximab impairs matrix metalloproteinases 2 and 9, epithelial-mesenchymal transition and cell migration in feline oral squamous cell carcinoma in vitro

Feline oral squamous cell carcinoma (FOSCC) is characterised by invasive and metastatic behaviour and is poorly responsive to current treatments, hence the need for new therapeutic strategies. FOSCC shares molecular targets with human head and neck squamous cell carcinoma (HNSCC), among these the epidermal growth factor receptor. Cetuximab is an anti-epidermal growth factor receptor monoclonal antibody employed in the therapy of HNSCC and, interestingly, previous work in vitro suggested that it displays cytostatic and cytotoxic properties also against FOSCC. With the present study, we aimed at further investigating the effects of cetuximab on invasion and metastasis pathways proven to be relevant in human patients. To this purpose, FOSCC cell lines SCCF1, SCCF2 and SCCF3 were treated with cetuximab for 48/72 h and subjected to Western blot for matrix metalloproteinases-2/9 (MMP-2/9) and epithelial-mesenchymal transition markers vimentin, E-, P- and N-cadherin. Treatment with cetuximab resulted in downregulation of MMP-2/-9 in all of the three cell lines in a dose-dependent manner. Moreover, cetuximab downregulated vimentin and P-cadherin in SCCF1, upregulated E-cadherin whilst downregulating P-/N-cadherins in SCCF2, and impaired P-/N-cadherins in SCCF3. An in vitro scratch test also demonstrated that cetuximab delayed cell migration in SCCF3. These data suggest that cetuximab mitigates invasion and metastasis processes by impairing MMPs and epithelial-mesenchymal transition pathways in FOSCC, indicating that this monoclonal antibody may help to counteract malignant progression and improve the management of locally invasive disease.

Upregulation of miR-519d-3p Inhibits Viability, Proliferation, and G1/S Cell Cycle Transition of Oral Squamous Cell Carcinoma Cells Through Targeting CCND1

Background: MicroRNA (miR)-519d-3p suppresses tumor development, however, its role in oral squamous cell carcinoma (OSCC) has yet to be determined. Materials and Methods: OSCC and adjacent tissues were collected (n = 45 for adjacent; n = 21 for Stage I-II OSCC; n = 24 for Stage III-IV OSCC). The cell viability, proliferation, and cell cycle of OSCC were, respectively, assessed by the Cell Counting Kit-8 (CCK-8), colony formation assay, and flow cytometry. Relative expressions of cell cycle-regulated proteins (Cyclin D1 [CCND1], CDK4, and CDK6) and miR-519d-3p were measured with Western blot and quantitative real-time polymerase chain reaction as needed. Dual-luciferase reporter assay was performed to verify the prediction of TargetScan that miR-519d-3p and CCND1 shared potential binding sites. Correlation analysis between miR-519d-3p and CCND1 was performed with Pearson's correlation test. Results: In OSCC tissues, downregulating miR-519d-3p expression correlated with a higher tumor grade. Upregulating miR-519d-3p expression inhibited OSCC cell viability and proliferation, increased cells in G0/G1 phase and reduced those in S/G2 phase, and downregulated the expressions of cell cycle-related protein (CDK4, CDK6). CCND1 was the target gene of miR-519d-3p, and overexpressed CCND1 reversed the effects of upregulation of miR-519d-3p on suppressing the viability, proliferation, and cell cycle of OSCC cells. Conclusions: miR-519d-3p upregulation suppressed the cell viability, proliferation, and G1/S cell cycle transition of OSCC through targeting CCND1. The current findings provide a possible clinical option for OSCC treatment.

miR-626 Inhibition Enhanced the Radiosensitivity to Oral Squamous Cell Carcinoma via the Downregulation of Nuclear Factor Kappa-B Signaling

Objective: The effect of miR-626 on the radiosensitivity to oral squamous cell carcinoma (OSCC) was evaluated in this study. Materials and Methods: The level of miR-626 in OSCC patients was determined by analyzing the data of miRNA microarray GSE113956. miR-626 was overexpressed by miR-626 mimics and knockdown were performed by miR-626 inhibitor. The level of miR-626 was detected by quantitative real-time polymerase chain reaction. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assays were used to detect the effect of miR-626 on the growth of OSCC cells. Flow cytometry was used to detect the apoptosis of OSCC cells. Western blot and dual luciferase reporter assays were used to explore the underlying mechanism of miR-626 regulating the radiosensitivity to OSCC. The effect of miR-626 on the radiosensitivity to OSCC were examined in an in vivo xenograft model. Results: The serum miR-626 level of OSCC patients was significantly higher than that of healthy controls. miR-626 mimics significantly promoted the OSCC cell growth, but the miR-626 inhibitor significantly suppressed the OSCC cell growth. Radiation combined with the miR-626 inhibitor significantly suppressed the cell proliferation and promoted the apoptosis of SCC-4 and HSC4 cells. Moreover, miR-626 regulates the nuclear factor kappa-B (NF-κB) signaling mediated by TRAF-interacting protein with forkhead-associated domain B. Furthermore, inhibition of miR-626 enhances the radiosensitivity to OSCC in nude mice. Conclusions: miR-626 inhibition enhanced the radiosensitivity to OSCC through the downregulation of NF-κB signaling.

Knockdown of TFAP2E results in rapid G2/M transition in oral squamous cell carcinoma cells

TFAP2E is a member of the activator protein-2 transcription factor family and acts as a tumor suppressor in several types of cancer. Downregulation of TFAP2E expression is significantly associated with a shorter overall survival period in patients with oral squamous cell carcinoma (OSCC). To evaluate the molecular mechanisms by which TFAP2E suppresses the development or progression of OSCC, the present study investigated the effects of TFAP2E downregulation on OSCC-derived Ca9-22 and HSC-4 cells. The present study demonstrated that small interfering RNA mediated-knockdown of TFAP2E accelerated the proliferation of these OSCC cell lines compared with that in the control group, as determined by the standard water-soluble tetrazolium salt-8 assay. To analyze the cell cycle progression rate, the cell cycle distribution patterns of TFAP2E-knockdown and control cells cultured in the presence of nocodazole, which prevents the completion of mitosis, were analyzed by fluorescence-activated cell sorting at different time points. When analyzing cellular DNA contents, no major differences in cell cycle profiles were observed; however, the rate of increase in cells positive for histone H3 Serine 28 phosphorylation, a standard molecular marker of early M phase, was significantly higher in TFAP2E-knockdown cells than in the control cells. Collectively, these results suggested that TFAP2E may attenuate the proliferation of OSCC cells by regulating G2/M transition.

Hippo-YAP signaling activation and cross-talk with PI3K in oral cancer: A retrospective cohort study

OBJECTIVES

This study aimed to investigate the clinical and prognostic relevance of the Hippo-YAP transactivators YAP1 and TAZ in oral squamous cell carcinoma, and their possible relationship with PI3K/mTOR pathway activation.

MATERIALS AND METHODS

Immunohistochemical analysis of YAP1, TAZ, PIK3CA (p110α), p-AKT (Ser473), and p-S6 (Ser235) was performed in paraffin-embedded tissue specimens from 165 OSCC patients. Correlations between protein expression and clinical data were further assessed.

RESULTS

YAP1 expression was detected in both cytoplasm and nucleus of tumor cells, whereas TAZ expression was only found in the nucleus. Nuclear YAP1 was significantly associated with tumor size (p = 0.03), neck lymph node metastasis (p = 0.02), TNM stage (p = 0.02), and poor differentiation (p = 0.04). Nuclear TAZ was associated with tobacco (p = 0.03) and alcohol consumption (p = 0.04), and poor tumor differentiation (p = 0.04). There was a positive significant correlation between nuclear and cytoplasmic YAP1, nuclear TAZ, p110α expression, and mTORC1 activation p-S6 (S235). Combined expression of nuclear and cytoplasmic YAP1 was prognostic in both univariate and multivariate analyses. Active nuclear YAP1 was significantly and independently associated with poor disease-specific (p = 0.005, HR = 2.520; 95% CI = 1.319-4.816) and overall survival (p = 0.015, HR = 2.126; 95% CI = 1.155-3.916).

CONCLUSION

Nuclear YAP1 is an independent predictor of poor survival in oral squamous cell carcinoma.

Evaluation of Cytotoxic T Lymphocytes and Natural Killer Cell Distribution in Oral Squamous Cell Carcinoma and Oral Epithelial Dysplasia: An Immunohistochemical Study

Background The tumor microenvironment comprises stromal cells, a few immune cells, vascular channels, and an extracellular matrix. The immune cells play a pivotal role in arresting the development of various tumors by identifying and killing the abnormal tumor cells. These immune cells with cytotoxic function include the natural killer (NK) cells and CD8+ T lymphocytes. Human NK cells express the cell surface marker CD57 and can be identified by using monoclonal antibodies. CD8+ cytotoxic T cells are a critical subpopulation of T cells and are important mediators of adaptive immunity. The anti-tumor immunity is important to assess the prognosis of tumors and develop new therapies. This study aimed to evaluate the immunohistochemical expression of CD8 and CD57 immune cells in oral squamous cell carcinoma (OSCC), oral epithelial dysplasia (OED), and normal oral mucosa. Methodology Clinically diagnosed and histopathologically confirmed cases of OSCC (n = 22), oral leukoplakia with OED (n = 22), and normal oral mucosa (n = 22) comprised the study groups. The tissue sections were subjected to immunohistochemical analysis for CD8 and CD57 expression by calculation of the mean labeling index. The results were statistically analyzed using a one-way analysis of variance, Bonferroni multiple comparison test, and Student's t-test. SPSS software version 20.0 (IBM Corp., Armonk, NY, USA) was used for the statistical analysis, and the significance level was set at 0.05. Results An overall statistically significant difference was obtained in the number of CD8+ T lymphocyte cells and CD57+ NK cells when compared between OSCC, OED, and normal oral mucosa (p = 0.01). Variations in the number of CD8+ T lymphocyte cells and CD57+ NK cells were observed when a comparison was made between OED and OSCC and between OSCC and normal mucosal samples (p = 0.01). The study results showed that the mean labeling index of CD8 and CD57 increased in OSCC when compared to OED and normal mucosa (p = 0.01). Conclusions Samples of OED with moderate or severe dysplasia and samples of OSCC were accompanied by a higher level of infiltrating immune cells such as T cells, B cells, NK cells, and macrophages when compared to normal mucosa. The results suggested that the expression of CD8 and CD57 cells increased from normal mucosa to OED and the highest expression was found in OSCC. CD8 and CD57 could be used as surrogate markers to assess the malignant potential of the lesion and to determine the prognosis of patients with oral cancer.

Capnocytophaga gingivalis is a potential tumor promotor in oral cancer

OBJECTIVES

To investigate the role of oral microbiome in promoting oral squamous cell carcinoma (OSCC) development.

MATERIALS AND METHODS

We investigated the salivary microbiome of 108 controls and 70 OSCC cases by16S rRNA gene sequencing and detected the fluorescence signal of OSCC-related pathological bacteria by fluorescence in situ hybridization assay (FISH). The invasion and migration assays were used to show the differences of invasive and migrative abilities between control and experimental groups. Quantitative real-time PCR and Western blotting were used to verify the epithelial-to-mesenchymal transition (EMT).

RESULTS

In our study, the overall microbiome abundance and composition were richer in the 108 controls than in the 70 OSCC cases. We demonstrated that Streptococcus, Capnocytophaga, Peptostreptococcus, and Lactobacillus were highly abundant in the saliva of OSCC patients by 16S rDNA sequencing and FISH. Moreover, we found that Capnocytophaga gingivalis (C. gingivalis) was highly presented in OSCC tissues by FISH. We focused on C. gingivalis and found that its supernatant induced OSCC cells to undergo EMT, causing the cells to acquire a mesenchymal phenotype associated with highly invasive and metastatic properties.

CONCLUSION

Taken together, these results indicated that C. gingivalis might invade OSCC tissues and played an important role in OSCC by promoting OSCC invasion and metastasis by inducing EMT. Hence, the role of C. gingivalis in cancer progression revealed a new direction for the research of OSCC.

miR-450b promotes cell migration and invasion by inhibiting SERPINB2 in oral squamous cell carcinoma

OBJECTIVE

microRNA-450b (miR-450b) plays an important role in cancer progression; however, its function in oral squamous cell carcinoma (OSCC) remains largely unknown. This study aimed to investigate the action mechanisms of miR-450b in OSCC.

MATERIALS AND METHODS

OSCC animal model was established via continuous induction with single-drug 7, 12-dimethylbenzo[a]anthracene (DMBA). Animal tissue samples were pathologically typed using haematoxylin-eosin (HE) staining. The Cancer Genome Atlas (TCGA) database was used to predict miR-450b and SERPINB2 expression in head and neck squamous cell carcinoma (HNSCC). qRT-PCR and Western blotting were used to detect gene and protein expression in OSCC tissue and cells, respectively. OSCC cell proliferation, growth, migration and invasion were detected using CCK-8, colony formation, transwell migration and matrigel invasion assays, respectively. Bioinformatic tools were used to predict miR-450b target genes. Dual-luciferase reporter assay was used to verify targeting between miR-450b and SERPINB2. Finally, small interfering RNA (siRNA) was used to reduce SERPINB2 expression to detect its effect on tumourigenesis.

RESULTS

Four stages of OSCC carcinogenesis (normal oral epithelium, simple epithelial hyperplasia, dysplasia and OSCC) were identified. miR-450b was found to be overexpressed in OSCC animal samples, HNSCC samples and human OSCC cells. Upregulation of miR-450b significantly promoted OSCC cell proliferation, colony formation, migration and invasion, while its downregulation had the opposite effect. SERPINB2 was found to be a miR-450b target gene, and its expression was negatively correlated with miR-450b expression. Altering SERPINB2 expression effectively inhibited OSCC cell invasion, metastasis and epithelial-mesenchymal transition (EMT).

CONCLUSIONS

miR-450b plays a key role in OSCC tumourigenesis by regulating OSCC cell migration, invasion and EMT via SERPINB2.

Prognosis of oral epithelial dysplasia in individuals with and without oral lichen planus

OBJECTIVES

To investigate the role of oral lichen planus (OLP) on the long-term prognosis of oral epithelial dysplasia (OED).

METHODS

Retrospective single-centre cohort study using the 2007-2019 database of the Head and Neck Cancer and Oral Medicine units of University College London Hospital. The exposure of interest was the presence of OLP, and the prognostic outcomes included the development of new primary episodes of OED, progression to malignancy and mortality. Cox proportional hazard and Poisson regression models were performed.

RESULTS

A total of 299 patients, of whom 144 had OED arising on the background of OLP (OLP/OED) and 155 had OED without underlying OLP (non-OLP/OED), were included. A pre-existing diagnosis of OLP was significantly associated with a twofold increased risk of subsequent primary OED events (HR = 2.02, p = 0.04), which also developed faster (1.46 vs. 2.96 years, p = 0.04) and with more involvement of non-cancer-prone sites (p = 0.001) than in the non-OLP/OED group. There was no difference between groups in the progression to malignancy or mortality.

CONCLUSIONS

Oral lichen planus/OED patients are at higher risk of multiple episodes of primary OED, which can develop faster and at non-cancer-prone sites as compared to non-OLP/OED individuals. Further research is needed to clarify the effects of OLP upon progression to OSCC and mortality.

PDZ-binding kinase inhibitor OTS514 suppresses the proliferation of oral squamous carcinoma cells

OBJECTIVE

PDZ-binding kinase (PBK) has been reported as a poor prognostic factor and is a promising molecular target for anticancer therapeutics. Here, we aimed to investigate the effect of specific PBK inhibitor OTS514 on the survival of OSCC cells.

METHODS

Four OSCC cell lines (HSC-2, HSC-3, SAS, and OSC-19) were used to examine the effect of OTS514 on cell survival and apoptosis. DNA microarray analysis was conducted to investigate the effect of OTS514 on gene expression in OSCC cells. Gene set enrichment analysis was performed to identify molecular signatures related to the antiproliferative effect of OTS514.

RESULTS

OTS514 decreased the cell survival of OSCC cells dose-dependently, and administration of OTS514 readily suppressed the HSC-2-derived tumor growth in immunodeficient mice. Treatment with OTS514 significantly increased the number of apoptotic cells and caspase-3/7 activity. Importantly, OTS514 suppressed the expression of E2F target genes with a marked decrease in protein levels of E2F1, a transcriptional factor. Moreover, TP53 knockdown attenuated OTS514-induced apoptosis.

CONCLUSION

OTS514 suppressed the proliferation of OSCC cells by downregulating the expression of E2F target genes and induced apoptosis by mediating the p53 signaling pathway. These results highlight the clinical application of PBK inhibitors in the development of molecular-targeted therapeutics against OSCC.

CXCL8, MMP12, and MMP13 are common biomarkers of periodontitis and oral squamous cell carcinoma

OBJECTIVE

To analysis the relationship between periodontitis (PD) and oral squamous cell carcinoma (OSCC) by bioinformatic analysis.

MATERIALS AND METHODS

We analyzed the gene expression profiles of PD (GSE16134) from the Gene Expression Omnibus (GEO) database and OSCC samples from TCGA-HNSC (head and neck squamous cell carcinoma) and identified common differentially expressed genes (DEGs) in PD and OSCC. Then, functional annotation and signaling pathway enrichment, protein interaction network construction, and hub gene identification were performed. Subsequently, the function and signaling pathway enrichment of hub genes, miRNA interaction, and transcription factor interaction analyses were carried out. We analyzed GSE10334 and GSE30784 as validation datasets, and performed qRT-PCR experiments simultaneously for validation, and obtained 4 hub genes. Finally, immune infiltration analysis and clinical correlation analysis of 4 hub genes and related miRNAs were performed.

RESULTS

We identified 31 DEGs (16 up-regulated and 15 down-regulated). Four hub genes were obtained by qRT-PCR and validation dataset analysis, including IL-1β, CXCL8, MMP12, and MMP13. The expression levels of them were all significantly upregulated in both diseases. The functions of these genes focus on three areas: neutrophil chemotaxis, migration, and CXCR chemokine receptor binding. Key pathways include IL-17 signaling pathway, chemokine signaling pathway, and cytokine-cytokine receptor interactions pathway. Immune infiltration analysis showed that the expressions of 4 hub genes were closely related to a variety of immune cells. ROC curve analysis indicated that AUCs of 4 hub genes are all greater than 0.7, among which MMP12 and MMP13 were greater than 0.9. Kaplan-Meier survival analysis indicated that worse OS was strongly correlated with CXCL8 and MMP13 high-expression groups. MMP12 low-expression group was strongly associated with worse OS. The results of multivariate Cox regression analysis showed that age, N stage, CXCL8, MMP12, and MMP13 were independent prognostic factors for OS. We also identified 3 miRNAs, including hsa-miR-19b-3p, hsa-miR-181b-2-3p, and hsa-miR-495-3p, that were closely related to 4 hub genes. Hsa-miR-495-3p is closely related to the diagnosis and prognosis of OSCC.

CONCLUSIONS

We identified 4 hub genes between PD and OSCC, including IL-1β, CXCL8, MMP12, and MMP13. These genes may mediate the co-morbid process of PD and OSCC through inflammation-related pathways such as the IL-17 signaling pathway. It is worth noting that CXCL8, MMP12, and MMP13 have great significance in the diagnosis and prognosis of OSCC.

Immune checkpoint CD161/LLT1-associated immunological landscape and diagnostic value in oral squamous cell carcinoma

An active host adaptive response is characterized by the existence of programmed cell death protein 1 (PD-1)+ /IFN-γ+ cytotoxic T cells and IFN-γ-induced PD-L1+ tumor cells (TCs), which predicts high response rate to anti-PD-1/L1 therapy. Recently, CD161 and its ligand LLT1 (CLEC2D) have been identified as an emerging checkpoint for immunotherapy. Clarifying its heterogeneous clinical expression pattern and its immune landscape is a prerequisite for maximizing the response rate of CD161 blockade therapy in a specific population of oral squamous cell carcinoma (OSCC) patients. Here, we investigated the expression pattern of CD161/LLT1 and its association with major immunocytes (T cells, B cells, NK cells, and macrophages) by multiplex immunofluorescence, immunohistochemistry, and flow cytometry in 109 OSCC tissues and 102 peripheral blood samples. TCs showed higher LLT1 levels than tumor infiltrating lymphocytes (TILs), whereas CD161 was highly expressed in CD8+ T cells at the tumor front, which was decreased in paracancerous tissue. High expression of TC-derived LLT1 (LLT1TC ) conferred poor clinical outcomes, whereas higher CD161+ and LLT1+ TILs were associated with better prognosis. Meanwhile, patients with high LLT1TC showed a decreased ratio of CD8+ /Foxp3+ T cells in situ, but CD161+ TILs correlated with more peripheral CD3+ T cells. Interestingly, treatment of OSCC patients with nivolumab (anti-PD-1) could restore tumoral CD161/LLT1 signal. Furthermore, an OSCC subgroup characterized by high LLT1+ TCs and low CD161+ CD8+ T cells showed fewer peripheral T cells and a higher risk of lymph node metastasis, leading to a shorter 5-year survival time (29%). More LLT1TC at the invasive front was another risk characteristic of exhausted T cells. In conclusion, in view of this heterogeneity, the LLT1/CD161 distribution pattern should be determined before CD161-based immunotherapy.

Hyperbaric oxygen enhances X-ray induced ferroptosis in oral squamous cell carcinoma cells

OBJECTIVE

The objective of this study was to investigate the combined effect of X-ray radiation (IR) and hyperbaric oxygen (HBO) on oral squamous cell carcinoma (OSCC) cells and to explore the possible molecular mechanism.

METHODS

The OSCC cells were treated with or without IR, together with or without HBO co-exposure. Cells were transfected with specific plasmids using Lipofectamine 2000. The cell varieties, apoptosis markers, and ferroptosis markers were determined by using appropriate method. OSCC xenograft mice model was categorized into several subgroups according to the specific treatement. GPX4 expressions were determined by immunohistochemistry (IHC) in OSCC tissues and were tested by ELISA in serums from OSCC patients.

RESULTS

The co-exposure of IR and HBO significantly strengthened the cytotoxicity of IR on SCC15-S cells in ferroptosis-dependent manner. The regulated GPX4/ferroptosis mediated the HBO function on re-sensitizing the radio-resistant OSCC cells to IR. In xenograft mice, co-exposure of IR and HBO can significantly reduce the tumor under IR activation compared with IR alone. Clinical data indicated that high GPX4 levels were associated with poor chemo-radiotherapy outcome.

CONCLUSIONS

HBO could re-sensitize radio-resistant OSCC cells through GPX4/ferroptosis regulation. These results provide a potential therapeutic strategy for clinical radio-resistance.

Role of Lymphovascular Invasion in Oral Cavity Squamous Cell Carcinoma Regional Metastasis and Prognosis

OBJECTIVE

The overall 5-year survival for oral squamous cell carcinoma (OSCC) has not changed in the last 20 years despite advances in treatment. Lymphovascular invasion (LVI) has been shown to be a negative prognostic factor in other cancers, however its role in the prognosis of OSCC remains unclear. This study aims to determine if LVI is a predictor of cervical lymph node metastasis and/or recurrence in OSCC.

METHODS

We conducted a retrospective cohort review of patients from our institutional cancer registry who were treated for OSCC between 2004 and 2018. Patient demographics, surgical pathology results, and clinical outcome data were collected. A multivariable logistic regression analysis was performed to determine if LVI was an independent predictor of cervical lymph node metastasis and/or recurrence.

RESULTS

442 patients were included, 32.8% were female and median age at time of diagnosis was 61.2 years. LVI was present in 32.8% of patients. When controlled for age, sex, t-classification, perineural invasion, depth of invasion (DOI), and margin status, LVI was a significant predictor of the presence of cervical node metastasis (OR: 3.42, CI: 2.17-5.39, P < .001). There was no significant association found between LVI and local recurrence (OR: 1.03, CI: 0.57-1.84, P = .92), regional recurrence (OR: 1.10, CI: 0.57-2.11, P = .78), or distant recurrence (OR: 1.59, CI: 0.87-2.94, P = .13).

CONCLUSION

The results of this study suggest that LVI is a significant predictor of the presence of cervical lymph node metastasis at presentation independent of other known prognostic factors. LVI, however, was not found to be a significant independent predictor of locoregional or distant recurrence.Level of Evidence: Level III.

A FACS-based novel isolation technique identifies heterogeneous CTCs in oral squamous cell carcinoma

Purpose

Isolating circulating tumour cells (CTCs) from the blood is challenging due to their low abundance and heterogeneity. Limitations of conventional CTC detection methods highlight the need for improved strategies to detect and isolate CTCs. Currently, the Food and Drug Administration (FDA)-approved CellSearch™ and other RUO techniques are not available in India. Therefore, we wanted to develop a flexible CTC detection/isolation technique that addresses the limitation(s) of currently available techniques and is suitable for various downstream applications.

Methods

We developed a novel, efficient, user-friendly CTC isolation strategy combining density gradient centrifugation and immuno-magnetic hematogenous cell depletion with fluorescence-activated cell sorting (FACS)-based positive selection using multiple CTC-specific cell-surface markers. For FACS, a stringent gating strategy was optimised to exclude debris and doublets by side scatter/forward scatter (SSC/FSC) discriminator, remove dead cells by 4',6-diamidino-2-phenylindole (DAPI) staining, and eliminate non-specific fluorescence using a "dump" channel. APC-labelled anti-CD45mAB was used to gate remaining hematogenous cells, while multiple epithelial markers (EpCAM, EGFR, and Pan-Cytokeratin) and an epithelial-mesenchymal transition (EMT) marker (Vimentin) labelled with fluorescein isothiocyanate (FITC) were used to sort cancer cells. The technique was initially developed by spiking Cal 27 cancer cells into the blood of healthy donors and then validated in 95 biopsy-proven oral squamous cell carcinoma (OSCC) patients. CTCs isolated from patients were reconfirmed by Giemsa staining, immuno-staining, and whole transcriptome amplification (WTA), followed by qRT-PCR. In vitro culture and RNA sequencing (RNA-Seq) were also performed to confirm their suitability for various downstream applications.

Results

The mean detection efficiency for the Cal 27 tongue cancer cells spiked in the whole blood of healthy donors was 32.82% ± 12.71%. While ~75% of our patients (71/95) had detectable CTCs, the CTC positivity was independent of the TNM staging. The isolated potential cancer cells from OSCC patients were heterogeneous in size. They expressed different CTC-specific markers in various combinations as identified by qRT-PCR after WTA in different patients. Isolated CTCs were also found to be suitable for downstream applications like short-term CTC culture and RNA-Seq.

Conclusion

We developed a sensitive, specific, flexible, and affordable CTC detection/isolation technique, which is scalable to larger patient cohorts, provides a snapshot of CTC heterogeneity, isolates live CTCs ready for downstream molecular analysis, and, most importantly, is suitable for developing countries.

Neoadjuvant Radiochemotherapy Alters the Immune and Metabolic Microenvironment in Oral Cancer-Analyses of CD68, CD163, TGF-β1, GLUT-1 and HIF-1α Expressions

BACKGROUND

The first-line treatment of oral squamous cell carcinoma (OSCC) involves surgical tumor resection, followed by adjuvant radio(chemo)therapy (R(C)T) in advanced cases. Neoadjuvant radio- and/or chemotherapy has failed to show improved survival in OSCC. Recently, neoadjuvant immunotherapy has shown promising therapeutic efficacy in phase 2 trials. In this context, the addition of radio- and chemotherapy is being reconsidered. Therefore, a better understanding of the tumor-biologic effects of neoadjuvant RCT would be beneficial. The current study was conducted on a retrospective cohort of patients who received neoadjuvant RCT for the treatment of oral cancer. The aim of the study was to evaluate the influence of neoadjuvant RCT on the immunological tumor microenvironment (TME) and hypoxic and glucose metabolisms.

METHODS

A cohort of 45 OSSC tissue samples from patients were analyzed before and after RCT (total 50.4 Gy; 1.8 Gy 5× weekly; Cisplatin + 5-Fluorouracil). Immunohistochemistry for CD68, CD163, TGF-β, GLUT-1 and HIF-1α was performed using tissue microarrays and automated cell counting. Differences in expression before and after RCT and associations with histomorphological parameters (T-status, N-status) were assessed using the Mann-Whitney U test.

RESULTS

Tumor resection specimens after neoadjuvant RCT showed a significant decrease in CD68 infiltration and a significant increase in CD163 cell density. The CD68/CD163 ratio was significantly lower after RCT, indicating a shift toward M2 polarization. The GLUT-1 and HIF-1α expressions were significantly lower after RCT. Larger tumors (T3/T4) showed a lower GLUT-1 expression. Other biomarkers were not associated with the T- and N-status.

CONCLUSIONS

Neoadjuvant RCT with 50.4 Gy induced a shift toward the M2 polarization of macrophages in the TME. This change in immune composition is not favorable and may be prognostically negative and counteract immunotherapeutic approaches. In addition, the decreased expressions in GLUT-1 and HIF-1α indicate reductions in the glucose metabolism and hypoxic energy metabolism in response to "high dose" neoadjuvant RCT, which may be therapeutically desirable.

Tetraspanin CD82 Correlates with and May Regulate S100A7 Expression in Oral Cancer

Many metastatic cancers with poor prognoses correlate to downregulated CD82, but exceptions exist. Understanding the context of this correlation is essential to CD82 as a prognostic biomarker and therapeutic target. Oral squamous cell carcinoma (OSCC) constitutes over 90% of oral cancer. We aimed to uncover the function and mechanism of CD82 in OSCC. We investigated CD82 in human OSCC cell lines, tissues, and healthy controls using the CRISPR-Cas9 gene knockout, transcriptomics, proteomics, etc. CD82 expression is elevated in CAL 27 cells. Knockout CD82 altered over 300 genes and proteins and inhibited cell migration. Furthermore, CD82 expression correlates with S100 proteins in CAL 27, CD82KO, SCC-25, and S-G cells and some OSCC tissues. The 37-50 kDa CD82 protein in CAL 27 cells is upregulated, glycosylated, and truncated. CD82 correlates with S100 proteins and may regulate their expression and cell migration. The truncated CD82 explains the invasive metastasis and poor outcome of the CAL 27 donor. OSCC with upregulated truncated CD82 and S100A7 may represent a distinct subtype with a poor prognosis. Differing alternatives from wild-type CD82 may elucidate the contradictory functions and pave the way for CD82 as a prognostic biomarker and therapeutic target.

HOXA1 3'UTR Methylation Is a Potential Prognostic Biomarker in Oral Squamous cell Carcinoma

BACKGROUND

HOXA1 is a prognostic marker and a potential predictive biomarker for radioresistance in head and neck tumors. Its overexpression has been associated with promoter methylation and a worse prognosis in oral squamous cell carcinoma (OSCC) patients. However, opposite outcomes are also described. The effect of the methylation of this gene on different gene regions, other than the promoter, remains uncertain. We investigated the methylation profile at different genomic regions of HOXA1 in OSCC and correlated differentially methylated CpG sites with clinicopathological data.

METHODS

The HOXA1 DNA methylation status was evaluated by analyzing data from The Cancer Genome Atlas and three Gene Expression Omnibus datasets. Significant differentially methylated CpG sites were considered with a |∆β| ≥ 0.10 and a Bonferroni-corrected p-value < 0.01. Differentially methylated CpGs were validated by pyrosequencing using two independent cohorts of 15 and 47 OSCC patients, respectively.

RESULTS

Compared to normal tissues, we found significantly higher DNA methylation levels in the 3'UTR region of HOXA1 in OSCC. Higher methylation levels in tumor samples were positively correlated with smoking habits and patients' overall survival.

CONCLUSIONS

Our findings suggest that HOXA1 gene body methylation is a promising prognostic biomarker for OSCC with potential clinical applications in patient monitoring.