Oral Cavity Squamous Cell Carcinoma Risk Factors: State of the Art

Current knowledge of ferroptosis in the pathogenesis and prognosis of oral squamous cell carcinoma

Therapeutic strategies are the hot-spot issues in treating patients with advanced oral squamous cell carcinoma (OSCC). Mounting studies have proved that triggering ferroptosis is one of the promising targets for OSCC management. In this study, we performed a first attempt to collect the current evidence on the proposed roles of ferroptosis in OSCC through a comprehensive review. Based on clinical data from the relevant studies within this topic, we found that ferroptosis-associated tumor microenvironment, ferroptosis-related genes (FRGs), and ferroptosis-related lncRNAs exhibited a potent prognostic value for OSCC patients. Mechanistically, experimental data revealed that the proliferation and tumorigenesis of OSCC might be associated with the inhibition of cellular ferroptosis through the activation of glutathione peroxidase 4 (GPX4) and adipocyte enhancer-binding protein 1 (AEBP1), suppression of glutathione (GSH) and Period 1 (PER1) expression, and modulation of specific non-coding RNAs (i.e., miR-520d-5p, miR-34c-3p, and miR-125b-5p) and their targeted proteins. Several specific interventions (i.e., Quisinostat, Carnosic acid, hyperbaric oxygen, melatonin, aqueous-soluble sporoderm-removed G. lucidum spore powder, and disulfiram/copper complex) were found to dramatically induce ferroptosis cell death of OSCC via multiple mechanisms. This review highlighted the pivotal role of ferroptosis in the pathogenesis and prognosis of OSCC. Future anticancer therapeutic strategies targeting ferroptosis and its associated molecules might provide a new insight for OSCC treatment.

Synthesis of N2-trans-isosafrole-dG-adduct Bearing DNAs and the Bypass Studies with Human TLS Polymerases κ and η

Safrole is a natural product present in many plants and plant products, including spices and essential oils. During cellular metabolism, it converts to a highly reactive trans-isosafrole (SF) intermediate that reacts with genomic DNA and forms N2-SF-dG and N6-SF-dA DNA adducts, which are detected in the oral tissue of cancer patients with betel quid chewing history. To study the SF-induced carcinogenesis and to probe the role of low fidelity translesion synthesis (TLS) polymerases in bypassing SF adducts, herein, we report the synthesis of N2-SF-dG modified DNAs using phosphoramidite chemistry. The N2-SF-dG modification in the duplex DNA does not affect the thermal stability and retains the B-form of helical conformation, indicating that this adduct may escape the radar of common DNA repair mechanisms. Primer extension studies showed that the N2-SF-dG adduct is bypassed by human TLS polymerases hpolκ and hpolη, which perform error-free replication across this adduct. Furthermore, molecular modeling and dynamics studies revealed that the adduct reorients to pair with the incoming nucleotide, thus allowing the effective bypass. Overall, the results indicate that hpolκ and hpolη do not distinguish the N2-SF-dG adduct, suggesting that they may not be involved in the safrole-induced carcinogenicity.

SCUBE3 Exerts a Tumor-Promoting Effect in Tongue Squamous Cell Carcinoma by Promoting CEBPA Binding to the CCL2 Promoter

Tongue squamous cell carcinoma (TSCC) is the main pathologic subtype of oral cancer, and the current therapeutic effect is far from satisfactory. The signal peptide-CUB-EGF domain-containing protein 3 (SCUBE3) has been shown to be a tumor-promoting factor in several malignancies. However, little is known about the role of SCUBE3 in TSCC. In this study, we identified that SCUBE3 was highly expressed in TSCC. Clinically, high expression of SCUBE3 was positively associated with tumor stage and T stage of TSCC. Functionally, SCUBE3 silence remarkably restrained cell proliferation, migration, and invasion, induced apoptosis as well as cell cycle arrest in G2-phase, and weakened the tumorigenicity of TSCC cells in vivo. Mechanistically, SCUBE3 promoted the direct binding of CCAAT enhancer binding protein alpha (CEBPA) to C-C motif chemokine ligand 2 (CCL2) promoter in TSCC cells. Interestingly, CCL2 overexpression partially reversed the inhibitory effect of SCUBE3 deficiency on TSCC cell viability and migration. Moreover, STAT3 signaling contributed to CCL2-mediated phenotypes in TSCC cells.

IMPLICATIONS

Our data revealed a tumor-promoting role for SCUBE3 in TSCC via the CEBPA/CCL2/STAT3 axis, which provided new insight into novel potential therapeutic target for TSCC.

Exogenous Estrogen in the Development of Head and Neck Cancer

Importance

Sex differences in head and neck cancer (HNC) incidence suggest a potential contribution of sex hormones.

Objective

To assess the role of exogenous estrogen exposure in the development of HNC in female patients.

Design, Settings, and Participants

This large multicenter cohort study using clinical records from the TriNetX real-world database included 20 years of data (through May 31, 2023) from 87 health care organizations. The TriNetX database was searched for medical records for female patients with and without exogenous estrogen exposure according to their chronological age. Cohort 1 included 731 366 female patients aged 18 to 45 years old with regular oral contraceptive (OC) intake and cohort 2 included 3 886 568 patients in the same age group who did not use OC. Cohort 3 comprised 135 875 female patients at least 50 years old receiving hormone replacement therapy (HRT), whereas cohort 4 included 5 875 270 patients at least 50 years old without HRT. Propensity score matching was performed for the confounders age, alcohol dependence, and nicotine dependence. Data analyses were performed in May 2023.

Main Outcome and Measures

Diagnosis of HNC (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision: C00-C14), and after propensity score matching (1:1 nearest-neighbor greedy matching), a risk analysis to investigate risk differences and risk ratios (RRs) with a 95% CI.

Results

Among the 718 101 female patients in each of cohorts 1 and 2 (mean [SD] age at diagnosis, 25.9 [6.7] years), those with OC intake had a higher risk of an HNC diagnosis (RR, 1.47; 95% CI, 1.21-1.78) than those without OC use. Among the 131 835 female patients in each of cohorts 3 and 4 (mean [SD] age, 67.9 [12.0] years), those with postmenopausal HRT intake had a lower risk of an HNC diagnosis (RR, 0.77; 95% CI, 0.64-0.92) than those without HRT use.

Conclusions and Relevance

The findings of this cohort study illustrate a positive association between OC and a negative association between HRT and the development of HNC in female patients. Given the limitations of the TriNetX database, future research should include detailed information on the intake of OC and HRT and reproductive health information (eg, age at menarche/menopause, number of pregnancies) to more accurately define the strength and direction of the possible association between exogeneous estrogen exposure and the development of HNC in female patients.

The Role of Estrogen and Estrogen Receptors in Head and Neck Tumors

Head and neck squamous cell carcinoma (HNSCC) is the most common histological form of head and neck tumors (HNTs), which originate from the epithelium of the lips and oral cavity, pharynx, larynx, salivary glands, nasal cavity, and sinuses. The main risk factors include consumption of tobacco in all forms and alcohol, as well as infections with high-risk human papillomaviruses or the Epstein-Barr virus. Regardless of the etiological agent, the risk of developing different types of HNTs is from two to more than six times higher in males than in females. The reason for such disparities probably lies in a combination of both biological and psychosocial factors. Therefore, it is hypothesized that exposure to female sex hormones, primarily estrogen, provides women with protection against the formation and metastasis of HNTs. In this review, we synthesized available knowledge on the role of estrogen and estrogen receptors (ERs) in the development and progression of HNTs, with special emphasis on membrane ERs, which are much less studied. We can summarize that in addition to epidemiologic studies unequivocally pointing to the protective effect of estrogen in women, an increased expression of both nuclear ERs, ERα, and ERβ, and membrane ERs, ERα36, GPER1, and NaV1.2, was present in different types of HNSCC, for which anti-estrogens could be used as an effective therapeutic approach.

RUVBL1 accelerates tongue squamous cell carcinoma by mediating CRaf/MEK/ERK pathway

RAF/MEK/ERK pathway is frequently activated in tumor. Therefore, this study will investigate the function of RUVBL1 (RAF-binding protein) in tongue squamous cell carcinoma (TSCC). Bioinformatics was performed to identify differentially expressed mRNAs (DE-mRNAs) in TCGA-oral squamous cell carcinoma, GSE13601, and GSE34105 datasets. A total of 672 shared DE-mRNAs were identified in three datasets, and they are regulating metastasis and angiogenesis. Patients with RUVBL1 low expression had high overall survival. Overexpressing RUVBL1 enhanced the viability, wound healing percentage, invasion, sphere formation, angiogenesis, and resistance to cisplatin and 5-fluorouracil in CAL-27 and SCC-4 cells, and the opposite results were obtained by knocking down RUVBL1. Moreover, overexpression of RUVBL1 bolstered tumor growth in vivo. Strikingly, RUVBL1 diminished the phosphorylation of CRAF Ser259, which led to activation of the MEK/ERK pathway. In conclusion, RUVBL1 contributes to the malignant biological behavior of TSCC via activating the CRAF/MEK/ERK pathway. This provides molecular mechanisms and perspectives for targeted therapy of the CRAF/MEK/ERK pathway.

Understanding PI3K/Akt/mTOR signaling in squamous cell carcinoma: mutated PIK3CA as an example

Compared with those in adenocarcinoma, PIK3CA mutations are more common in squamous cell carcinoma (SCC), which arises from stratified squamous epithelia that are usually exposed to adverse environmental factors. Although hotspot mutations in exons 9 and 20 of PIK3CA, including E542K, E545K, H1047L and H1047R, are frequently encountered in the clinic, their clinicopathological meaning remains to be determined in the context of SCC. Considering that few reviews on PIK3CA mutations in SCC are available in the literature, we undertook this review to shed light on the clinical significance of PIK3CA mutations, mainly regarding the implications and ramifications of PIK3CA mutations in malignant cell behavior, prognosis, relapse or recurrence and chemo- or radioresistance of SCC. It should be noted that only those studies regarding SCC in which PIK3CA was mutated were cherry-picked, which fell within the scope of this review. However, the role of mutated PIK3CA in adenocarcinoma has not been discussed. In addition, mutations occurring in other main members of the PI3K-AKT-mTOR signaling pathway other than PIK3CA were also excluded.

Second primary squamous cell carcinoma of the oral cavity - a retrospective cohort study of therapeutic procedures and oncological outcome

OBJECTIVES

In the presented study, the occurrence rates of second primary oral carcinomas and their prognostic relevance were analyzed.

MATERIALS AND METHODS

All patients with surgically treated oral squamous cell carcinomas within the years 2010 and 2022 in our department were included in this retrospective cohort study. Two groups were designed including patients with second primary carcinomas and patients with local tumor recurrences. Occurrence rates, tumor stages and applied therapies were assessed. Primary outcome was overall survival in dependence of the index tumor. Secondary outcomes were overall survival in dependence of local recurrences or second primary tumors.

RESULTS

An overall number of 908 patients was included in the analysis. 98 patients (10.8%) developed a second primary oral squamous cell carcinoma. Patients with second primary tumors presented significantly (p < 0.001) better overall survival in dependence of the index tumor compared to patients suffering from local recurrences. There was no significant difference in overall survival (p = 0.4) in dependence of the date of second primary tumor or local recurrence. Patients with second primary tumors were more likely to receive surgery-based therapy compared to patients with local recurrences who more frequently received definitive radiotherapy.

CONCLUSION

Our data indicates different clinical courses in terms of therapy and survival of patients suffering from second primary tumors compared to patients with local tumor recurrences. This may be due to a more aggressive biology of local recurrences and earlier detection of second primaries due to oncological follow-up of the index tumor.

CLINICAL RELEVANCE

The differentiation of local tumor recurrences and second primary tumors is of clinical relevance, as applicable therapies and resulting prognosis may differ significantly.

Serum cell division control 42 reflects treatment response and survival profiles in recurrent or metastatic oral squamous cell carcinoma patients who receive programmed death-1 inhibitors

OBJECTIVES

Cell division control 42 (CDC42) facilitates tumor growth, migration, and immune escape to accelerate the pathogenesis and progression of oral squamous cell carcinoma (OSCC). This study intended to explore the optimal cut-value of serum CDC42 for predicting treatment response to programmed death-1 (PD-1) inhibitors and survival in recurrent or metastatic (R/M) OSCC patients.

METHODS

CDC42 was detected from serum by enzyme-linked immunosorbent assay in 45 R/M OSCC patients before initiating PD-1 inhibitors with or without chemotherapy. Different cutoff values (500, 600, 700, and 800 pg/mL) of CDC42 were selected for further analyses.

RESULTS

The median (interquartile range) value of CDC42 was 604.0 (477.5-867.5) pg/mL in R/M OSCC patients. Generally, objective response rate (ORR) and disease control rate (DCR) were 37.8 % and 62.2 %. Additionally, ORR (P = 0.030) and DCR (P = 0.004) were decreased in patients with CDC42 ≥ 700 pg/mL versus those with CDC42 < 700 pg/mL; meanwhile, DCR was also reduced in patients with CDC42 ≥ 800 pg/mL versus those with CDC42 < 800 pg/mL (P = 0.014). Interestingly, CDC42 ≥ 600 (P = 0.023), 700 (P = 0.007), and 800 (P = 0.039) pg/mL were related to shorter progression-free survival (PFS). While only CDC42 ≥ 700 (P = 0.004) and 800 (P = 0.046) pg/mL were correlated with worse overall survival (OS). After adjustment, only CDC42 ≥ 700 pg/mL (yes vs. no) independently estimated poor PFS (hazard ratio (HR) = 2.637, P = 0.005) and OS (HR = 5.824, P < 0.001).

CONCLUSION

CDC42 ≥ 700 pg/mL exerts the optimal prognostic ability to reflect poor treatment response and survival profiles in R/M OSCC patients who receive PD-1 inhibitors.

The role of the epithelial sentinels, Langerhans cells and γδT cells, in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) arises in the oral epithelium, a tissue in which immune surveillance is mediated by its primary resident leukocytes, Langerhans cells (LCs), and γδT cells. Under steady-state conditions, LCs and γδT cells play a critical role in maintaining oral mucosal homeostasis. As antigen-presenting cells of stratified epithelia, LCs respond to various challenges faced by the epithelium, orchestrating innate, and adaptive immune responses in order to resolve them. γδT cells also sense diverse epithelial insults and react rapidly through cytokine production and cytolytic activity. These epithelial sentinels are also considered to be the first leukocytes in the oral epithelium to encounter early carcinogenic events that have the potential of becoming OSCC. As evident in many malignancies, leukocyte populations help prevent cancer development although they also promote tumor progression. OSCC is no exception, as studies have reported both anti- and pro-tumor roles of LCs and γδT cells. In this review, we summarize the ontogeny of LCs and γδT cells in the oral epithelium and discuss their role in OSCC.

The Interaction between CLSPN Gene Polymorphisms and Alcohol Consumption Contributes to Oral Cancer Progression

Most disease single nucleotide polymorphisms (SNPs) are regulatory and approximately half of heritability is occupied by the top 1% of genes, with the gene-level structure varying with the number of variants associated with the most common alleles. Cancer occurrence and progression are significantly affected by Claspin (CLSPN) gene polymorphism present in the population, which alters the expression, function, and regulation of the gene. CLSPN genotypes are associated with oral cancer, but the literature on this association is limited. As a result, the goal of this study is to investigate the correlation between CLSPN genotypes and oral cancers' development. This study will explore the presence of four CLSPN SNPs including rs12058760, rs16822339, rs535638 and rs7520495 gene polymorphisms, and analyze the expression of these genes in 304 cancer-free controls and 402 oral squamous cell carcinoma (OSCC) cases. Attempts have been made to obtain insight into the role of CLSPN gene polymorphisms in oral cancer through the analysis of this study. We demonstrated that the OSCC risk of individuals with four CLSPN SNPs relative to the wild type did not differ significantly from that of the wild type when the polymorphisms are analyzed according to individual habits. We further studied the mechanism by which CLSPN polymorphisms affect the progression of clinicopathological features in OSCC patients. The results of the degree of cell differentiation showed that compared with patients of rs7520495 SNP carrying the CC genotype, the incidence of poor cell differentiation in patients carrying the CC + GG genotype was higher (AOR: 1.998-fold; 95% CI, 1.127-3.545; p = 0.018). In particular, patients with the G genotype of rs7520495 had increased poor cell differentiation compared with patients with the C genotype (AOR: 4.736-fold; 95% CI, 1.306-17.178; p = 0.018), especially in the drinking group. On the basis of our analysis of the Cancer Genome Atlas dataset, we found that higher CLSPN levels were associated with poorer cell differentiation in oral cancers. In this study, we provide the first evidence showing that CLSPN SNPs contribute to oral cancer. Whether or not rs7520495 can be used as a confirmatory factor in the future is uncertain, but it seems likely that it can be used as an important factor in predicting recurrence, response to treatment and medication toxicity to patients with oral cancer.

Candida species as potential risk factors for oral squamous cell carcinoma: Systematic review and meta-analysis

Oral squamous cell carcinoma (OSCC) is considered a multifactorial disease and has been associated with microbial infections, although the association with Candida spp. is still controversial. This systematic review focused on clinical trials which evaluated the relation between oral Candida spp colonization and OSCC. PubMed; Scopus; Embase; Web of Science and Scientific Direct were assessed. Independent reviewers conducted the diagram steps. For data extraction the PRISMA protocol was followed. The quality analysis of case-control studies was performed based on the Newcastle-Ottawa scale. Meta-analysis was performed to evaluate the frequency of Candida spp and the levels of microbial acetaldehyde production (MAP) being odds ratio (OR) the effect-measure applied. Eight and six studies were included in the qualitative analysis and meta-analysis, respectively. It was noted that there was a significantly higher frequency of Candida species (p = 0.0003/OR = 9.50) in patients diagnosed with OSCC than healthy patients, especially Candida krusei (p = 0.0167/OR=4.62). Candida spp., from oral cancer patients demonstrated significantly greater biofilm, biofilm metabolic activity, phospholipase, proteinase activity and a higher production of MAP (p = 0.0111/OR = 2.67). Candida species may have a potential role in OSCC development. Further studies should be conducted to elucidate the mechanism of action of Candida spp and others risk factors in the development of OSCC.

Current Approach and Future Directions in the Diagnosis and Prognosis of Keratinocyte Carcinomas

Keratinocyte carcinomas (KCs) are malignancies developed from keratinocytes or their precursors [...].