Oral squamous cell carcinoma: overview of current understanding of aetiopathogenesis and clinical implications

Dissecting the Proton Transport Pathway in Oral Squamous Cell Carcinoma: State of the Art and Theranostics Implications

Cancer cells overexpress proton exchangers at the plasma membrane in order acidify the extracellular matrix and maintain the optimal pH for sustaining cancer growth. Among the families of proton exchangers implicated in carcinogenesis, carbonic anhydrases (CAs), monocarboxylate transporters (MCTs), Na⁺/H⁺ exchangers (NHEs), sodium bicarbonate cotransporters (NBCs), and vacuolar ATPases (V-ATPases) are highlighted. Considerable research has been carried out into the utility of the understanding of these machineries in the diagnosis and prognosis of several solid tumors. In addition, as therapeutic targets, the interference of their functions has contributed to the discovery or optimization of cancer therapies. According to recent reports, the study of these mechanisms seems promising in the particular case of oral squamous cell carcinoma (OSCC). In the present review, the latest advances in these fields are summarized, in particular, the usefulness of proton exchangers as potential prognostic biomarkers and therapeutic targets in OSCC.

Immunoexpression of human leukocyte antigen-DR in actinic cheilitis and lower lip squamous cell carcinoma

The aim of this study was to evaluate the immunoexpression of human leukocyte antigen-DR (HLA-DR) in actinic cheilitis (AC) and lower lip squamous cell carcinoma (LLSCC), and to correlate the findings with clinical (tumor size/extent, regional lymph node metastasis, and clinical stage) and histopathological (grade of epithelial dysplasia and inflammatory infiltrate for AC and histopathological grade of malignancy for LLSCC) parameters. Twenty-four AC and 48 LLSCC cases (24 with regional nodal metastasis and 24 without regional nodal metastasis) were selected. The scores of immunopositive cells for HLA-DR in the epithelial component of the lesions were assessed and the results were analyzed statistically using the nonparametric Mann-Whitney test. Epithelial expression of HLA-DR was observed in only five (20.8%) cases of AC (two low-grade and three high-grade lesions), with a very low median score of immunopositivity. By contrast, expression of HLA-DR was found in most LLSCC (97.9%), with a relatively high median score of positive cells. The score of HLA-DR-positive cells tended to be higher in tumors with regional lymph node metastasis, tumors in advanced clinical stages, and low-grade tumors, but the difference was not statistically significant (p > 0.05). In addition, there was a tendency towards higher expression of HLA-DR in highly/moderately keratinized tumors, and tumors with little/moderate nuclear pleomorphism (p > 0.05). The results suggest a potential role of HLA-DR in lip carcinogenesis, particularly in the development and progression of LLSCC. The expression of this protein can be related to the degree of cell differentiation in these tumors.

Endothelin Signaling Contributes to Modulation of Nociception in Early-stage Tongue Cancer in Rats

BACKGROUND

Patients with early stage tongue cancer do not frequently complain of tongue pain. Endothelin-1 signaling is upregulated in the cancerous tongue at the early stage. We tested the hypothesis that endothelin-1 signaling contributes to the modulation of tongue nociception.

METHODS

Squamous cell carcinoma cells were inoculated into the tongue under general anesthesia. Lingual mechanical sensitivity under light anesthesia using forceps from days 1 to 21 (n = 8) and the amounts of endothelin-1 and β-endorphin in the tongue on days 6, 14, and 21 (n = 5 to 7) were examined after the inoculation. The effect of endothelin-A or µ-opioid receptor antagonism on the mechanical sensitivity was examined (n = 5 to 7).

RESULTS

Lingual mechanical sensitivity did not change at the early stage (days 5 to 6) but increased at the late stage (days 13 to 14). The amount of endothelin-1 increased (25.4 ± 4.8 pg/ml vs. 15.0 ± 5.2 pg/ml; P = 0.008), and endothelin-A receptor antagonism in the tongue induced mechanical hypersensitivity at the early stage (51 ± 9 g vs. 81 ± 6 g; P = 0.0001). The µ-opioid receptor antagonism enhanced mechanical hypersensitivity (39 ± 7 g vs. 81 ± 6 g; P < 0.0001), and the amount of β-endorphin increased at the early stage.

CONCLUSIONS

β-Endorphin released from the cancer cells via endothelin-1 signaling is involved in analgesic action in mechanical hypersensitivity at the early stage.

A combined analysis of maximum standardized uptake value on FDG-PET, genetic markers, and clinicopathological risk factors in the prognostic stratification of patients with resected oral cavity squamous cell carcinoma

OBJECTIVE

Clinical outcomes of patients with resected oral cavity squamous cell carcinoma (OCSCC) chiefly depend on the presence of specific clinicopathological risk factors (RFs). Here, we performed a combined analysis of FDG-PET, genetic markers, and clinicopathological RFs in an effort to improve prognostic stratification.

METHODS

We retrospectively reviewed the clinical records of 2036 consecutive patients with first primary OCSCC who underwent surgery between 1996 and 2016. Of them, 345 underwent ultra-deep targeted sequencing (UDTS, between 1996 and 2011) and 168 whole exome sequencing (WES, between 2007 and 2016). Preoperative FDG-PET imaging was performed in 1135 patients from 2001 to 2016. Complete data on FDG-PET, genetic markers, and clinicopathological RFs were available for 327 patients.

RESULTS

Using log-ranked tests based on 5-year disease-free survival (DFS), the optimal cutoff points for maximum standardized uptake values (SUV-max) of the primary tumor and neck metastatic nodes were 22.8 and 9.7, respectively. The 5-year DFS rates were as follows: SUVtumor-max ≥ 22.8 or SUVnodal-max ≥ 9.7 (n = 77) versus SUVtumor-max < 22.8 and SUVnodal-max < 9.7 (n = 250), 32%/62%, P < 0.001; positive UDTS or WES gene panel (n = 64) versus negative (n = 263), 25%/62%, P < 0.001; pN3b (n = 165) versus pN1-2 (n = 162), 42%/68%, P < 0.001. On multivariate analyses, SUVtumor-max ≥ 22.8 or SUVnodal-max ≥ 9.7, a positive UDTS/WES gene panel, and pN3b disease were identified as independent prognosticators for 5-year outcomes. Based on these variables, we devised a scoring system that identified four distinct prognostic groups. The 5-year rates for patients with a score from 0 to 3 were as follows: loco-regional control, 80%/67%/47%/24% (P < 0.001); distant metastases, 13%/23%/55%/92% (P < 0.001); DFS, 74%/58%/28%/7% (P < 0.001); and disease-specific survival, 80%/64%/35%/7% (P < 0.001) respectively.

CONCLUSIONS

The combined assessment of tumor and nodal SUV-max, genetic markers, and pathological node status may refine the prognostic stratification of OCSCC patients.

Changes in oral microbial profiles associated with oral squamous cell carcinoma vs leukoplakia

AIM

Oral squamous cell carcinoma (OSCC) is the most frequently occurring cancer among head and neck SCC worldwide. The identification of novel effective biomarkers for early detection may greatly improve the survival rate and prognosis of patients with OSCC. This study aimed to identify specific oral microbial profiles associated with OSCC.

METHODS

Saliva samples were collected from oral leukoplakia (OLK) and OSCC patients (N = 6 each) and healthy controls (HC; N = 4). Total bacterial genomic DNA was isolated and 16S rRNA gene survey was performed by next-generation sequencing of the V4 region. The relative distribution of abundance for phylogenetic groups was compared among the OSCC and OLK groups.

RESULTS

The 448 operational taxonomic units detected from the libraries were classified into 133 genera, 69 families, 41 orders, 26 classes and 12 phyla. The abundance of phyla Bacteroidetes and genus Solobacterium was notably higher in the OSCC group when compared with the OLK group, whereas those of genus Streptococcus was significantly lower in the OSCC group when compared with the OLK.

CONCLUSION

These changes in the salivary microbiome may have potential applications as a novel diagnostic tool for the early detection of OSCC.

Staphylococcus aureus induces COX-2-dependent proliferation and malignant transformation in oral keratinocytes

The COX-2/PGE₂ axis can play roles in mediating the progression of tumor. COX-2 induction was observed in oral cancer. In our previous study, we found Staphylococcus aureus, a pathogen prevalent in oral cancer, can activate the COX-2/PGE₂ pathway in human oral keratinocyte (HOK) cells. Here, we investigated the proliferation of HOK cells affected by COX-2 induction and the role of COX-2 induction in the malignant transformation of HOK cells. We found S. aureus was able to facilitate HOK cell proliferation through upregulating COX-2 expression. With the induction of COX-2, expression of oral cancer-associated genes cyclin D1 was upregulated and p16 was downregulated. Transcriptome analysis showed that the “NF−kappa B signaling pathway” and “TNF signaling pathway” had the highest enrichment of differentially expressed genes (DEGs) with COX-2 over-expression. Seven upregulated genes (jun, tlr4, cxcl1, lif, cxcl3, tnfrsf1β, and il1β) in these two pathways were critical for the increased proliferation of HOK cells and might be associated with COX-2. Malignant transformation of cells was evaluated by soft agar colony formation assay and S. aureus infection promoted HOK cell colony formation. These results suggest the potential of S. aureus to induce the infection-associated malignant transformation of oral epitheliums through COX-2 activation.

Inhibition of ROS/NUPR1-dependent autophagy antagonises repeated cadmium exposure -induced oral squamous cell carcinoma cell migration and invasion

Cadmium (Cd), an established carcinogen, is a risk factor for oral squamous cell carcinoma (OSCC). Macroautophagy/autophagy is proposed to play a pivotal role in Cd-mediated carcinogenic activity. However, the mechanisms underlying Cd-induced autophagy are poorly understood. In the present study, a CAL27 OSCC cell line exposed to 10^-6 M Cd for 8 weeks was used as a model system. Repeated Cd exposure induced significant migration and invasion of CAL27 cells. Furthermore, we showed that Cd increased the autophagic flux in CAL27 cells, as evidenced by the upregulation of LC3-II and the downregulation of P62/SQSTM1. The genetic blocking of autophagy inhibited Cd-induced migration and invasion, indicating a carcinogenic role of autophagy in Cd-treated CAL27 cells. Cd-induced NUPR1 expression, which contributes to lysosomal biogenesis and expression of autophagy-related gene, was found to mechanistically initiate autophagy in CAL27 cells. Of note, NUPR1 shRNA abolished Cd-induced autophagy both in vitro and in vivo. We also found that Cd triggered the generation of MDA in a xenograft tumour model and that N-acetyl-l-cysteine, a reactive oxygen species (ROS) scavenger, abrogated the effects of Cd on NUPR1-dependent autophagy in vivo. Taken together, these results demonstrate that ROS-dependent NUPR1-mediated autophagy plays an important role in repeated Cd exposure -induced cell growth, migration and invasion in OSCC cells.

Esophageal cancer related gene-4 inhibits the migration and proliferation of oral squamous cell carcinoma through BC200 lncRNA/MMP-9 and -13 signaling pathway

Esophageal cancer related gene-4 (ECRG4) inhibits the malignant phenotype of oral squamous cell carcinoma. However, the molecular mechanisms remain to be explored. Using the tongue carcinoma cell line, TCA8113 as a cell model, we showed that forced expression of ECRG4 down-regulated the expression of the BC200 long non-coding RNA (lncRNA) and matrix metalloproteinases (MMP-9 and MMP-13). Restoration of BC200 lncRNA rescued ECRG4-mediated down-regulation of MMP-9 and -13. Furthermore, over-expression of Ecrg4 inhibited cell proliferation and migration, which was abolished by forced expression of BC200 lncRNA in TCA8113 cells. Our results indicate that ECRG4 inhibits the malignant phenotype of TCA8113 cells most likely through suppression of BC200 lncRNA/MMPs signaling pathway, rationalizing that BC200 lncRNA may be a potential target for oral squamous cell carcinoma (OSCC) therapy.

Oral lichen planus and other confounding factors in narrow band imaging (NBI) during routine inspection of oral cavity for early detection of oral squamous cell carcinoma: a retrospective pilot study

Background

Narrow Band Imaging is a noninvasive optical diagnostic tool. It allows the visualization of sub-mucosal vasculature; four patterns of shapes of submucosal capillaries can be recognized, increasingly associated with neoplastic transformation. With such characteristics, it has showed high effectiveness for detection of Oral Squamous Cell Carcinoma. Still, scientific literature highlights several bias/confounding factors, such as Oral Lichen Planus. We performed a retrospective observational study on patients routinely examined with Narrow Band Imaging, investigating for bias, confounding factors and conditions that may limit its applicability.

Methods

Age, sex, smoking, use of dentures, history of head & neck radiotherapy, history of Oral Squamous Cell Carcinoma, site of the lesion and thickness of the epithelium of origin were statistically evaluated as possible bias/confounding factors. Pearson’s Chi-squared test, multivariate logistic regression, Positive Predictive Value, Negative Predictive Value, Sensitivity, Specificity, Positive Likelihood Ratio, Negative Likelihood Ratio and accuracy were calculated, normalizing the cohort with/without patients affected by Oral Lichen Planus, to acknowledge its role as bias/confounding factor.

Results

Five hundred fifty-six inspections were performed on 106 oral cavity lesions from 98 patients. Age, sex, smoking, use of dentures and anamnesis of Oral Squamous Cell Carcinoma were not found to influence Narrow Band Imaging. History of head & neck radiotherapy was not assessed due to insufficient sample. Epithelium thickness does not seem to interfere with feasibility. Presence of Oral Lichen Planus patients in the cohort led to false positives but not to false negatives. Among capillary patterns, number IV was the most significantly associated to Oral Squamous Cell Carcinoma (p < 0.001), not impaired by the presence of Oral Lichen Planus patients in the cohort (accuracy: 94.3, 95% confidence interval: 88.1–97.9%; odds ratio: 261.7, 95% confidence interval: 37.7–1815.5).

Conclusion

Narrow Band Imaging showed high reliability in detection of Oral Squamous Cell Carcinoma in a cohort of patients with oral cavity lesions not normalized for bias/confounding factors. Still, Oral Lichen Planus may lead to false positives. Narrow Band Imaging could help in the follow-up of patients with multiple lesions through detection of capillary pattern IV, which seems to be the most significantly associated to neoplastic epithelium.

Molecular alterations of mitochondrial D-loop in oral leukoplakia

BACKGROUND

Over the years, numerous studies proposed a crucial role of mutations of nuclear DNA in the carcinogenesis process. Of late, many researchers suppose that alterations of mitochondrial DNA should not be excepted from this analysis. Mutational analysis of mitochondrial DNA displayed that mitochondrial D-loop is assessed as a hotspot for molecular alterations in various types of malignant tumors encompassing oral squamous cell carcinoma. Squamous cell carcinoma is believed to emerge through precancerous stages, which might be merely morphologic aspects of cumulative genetic variations.

METHODS

In keeping with this model of molecular tumor progression, this study aimed to investigate the qualitative and quantitative alterations that might occur in mitochondrial D-loop in oral leukoplakia whether dysplastic or not by semiquantitation of a product of the polymerase chain reaction and sequence analyses of mitochondrial D-loop gene.

RESULTS

Statistically significant increases in the mean values of D-loop concentrations were observed across the dysplasia gradient of oral leukoplakia. Sequence analyses revealed the presence of point mutations in both dysplastic and nondysplastic oral leukoplakia but not in normal mucosa.

CONCLUSION

The results of this study suggested that quantitative and qualitative alterations in mitochondrial D-loop could be a promising molecular marker for early detection and progression of the malignancy.

Combination of 5-Florouracil and polyphenol EGCG exerts suppressive effects on oral cancer cells exposed to radiation

OBJECTIVE

Natural compounds such as epigallocatechin-3-gallate (EGCG) have previously shown chemotherapeutic properties with few side-effects. In our study, we evaluated the effects of combining EGCG with 5-fluorouracil (5-FU) and radiotherapy on oral squamous cell cancer. We evaluated whether the combination of lower doses of 5-FU with EGCG could be equally or more effective than the use of higher doses of 5-FU alone.

METHODS

Cell viability, migration and cell cycles were assayed in oral cancer cell lines treated with 5-FU, 5-FU + EGCG and radiation (0, 2.5 and 5 Gy).

RESULTS

This study found that the combination of EGCG with 5-FU reduced cell viability and migration distance compared to control samples and the same dose of 5-FU alone. Addition of EGCG increased the number of cells in the G2/M phase, while 5-FU arrested the cell cycle in phase S. Moreover, cell exposure to 5 Gy radiation decreased the effects of combining with EGCG.

CONCLUSIONS

In summary, the combination of EGCG and 5-FU reduced both cell viability and migration as well as altered the cell cycle to a greater extent than 5-FU alone.

Changes in the expression of the potassium channels TASK1, TASK3 and TRESK in a rat model of oral squamous cell carcinoma and their relation to malignancy

OBJECTIVES

Potassium channels have been proposed to promote cancer cell proliferation and metastases. Thus, we investigated the expression pattern of three 2-pore domain potassium channels (K2Ps) TASK1, TASK3 and TRESK in advanced oral squamous cell carcinoma (OSCC), the commonest oral malignancy.

DESIGN

We used 4-nitroquinoline-1-oxide (4-NQO) to induce high grade OSCC in male adult rats. We then used immunohistochemistry and Western blotting to study the distribution and expression pattern of TASK1, TASK3 and TRESK in normal versus cancerous tissue. We also examined the expression of β-tubulin III (β-tub3), a marker associated with resistance to taxane-based chemotherapy and poor patient prognosis, and its correlation with the K2Ps. Finally, we studied the expression of TASK1, TASK3 and TRESK in human samples of SCC of oral origin.

RESULTS

We found that TASK3 was significantly up-regulated whereas TASK1 and TRESK were both significantly down-regulated in advanced, poorly differentiated OSCC. Both, rat and human SCC showed a significant increase in the expression of β-tub3. Interestingly, the expression of the latter correlated positively and significantly with TASK3 and TRESK but not TASK1 in rat OSCC. Our initial results showed a similar pattern of up and down regulation and correlation with β-tub3 for these three K2Ps in human SCC.

CONCLUSIONS

The changes in expression and the co-localization with a marker of resistance to taxanes like β-tub3 turn TASK1, TASK3 and TRESK into potentially new prognostic tools and possibly new therapeutic targets for OSCC.

Dental management prior to radiation therapy in patients with head and neck cancer

INTRODUCTION

Patients diagnosed with head and neck tumors, are treated by surgery, radiation therapy (RT), chemotherapy (CT) or a combination thereof. The goal is to describe the management protocol for patients subjected to radiation therapy (RT) and to study their long-term oral health status.

MATERIALS AND METHODS

A retrospective study was performed in a sample of 50 patients. We analyzed the oral health status and all the variables included applying the adapted protocol of pre-RT.

RESULTS

Prior to RT, 84% of patients required scaling and 32% conservative treatment. Around 74% of patients required at least one exodontia. The mean of exodontias for patients presenting Grade 3 of oral hygiene was 6.50 per person (p<0.0001). The pre-RT study of possible candida infection showed that 78% of patients were negative for this infection. The mean resting saliva production was 39.10 (SD: 23.30; range: 13-145), with a stimulated value of 64.78 (SD: 33.92; range: 16-200).

CONCLUSIONS

All patients should be protocoled to ensure that they present optimal oral conditions prior to initiating RT treatment.

Honey in oral health and care: A mini review

BACKGROUND

Honey is a natural product made from the nectar of flowers by honey bees and has over 200 compounds in it, including sugars, water, organic acids, minerals and polyphenols - the exact structure and composition of honey often determined by which plant source(s) the honey bee took the nectar from. Honey has been used in diets and medicines for thousands of years; however, this review, for the first time, aims to look at its place in modern medicine concerning oral health.

HIGHLIGHT

The present review for the first time attempted to address the protective effect of honey in the oral care.

CONCLUSION

For the first time this review addresses the usefulness of honey against Streptococcus mutans infections, dental plaque and caries, gingivitis and halitosis. Honey was also useful in preventing side effects associated with treatment of cancers of the head and neck, namely, radiation induced mucositis, xerostomia and poor wound healing. This is well supported by evidence in literature and was examined in this review.

Evodiamine inactivates NF-κB and potentiates the antitumor effects of gemcitabine on tongue cancer both in vitro and in vivo

Objective

The aim of this study was to investigate whether evodiamine (EVO) could potentiate the antitumor activity of gemcitabine (GEM) in tongue cancer cells and determine its potential underlying mechanisms.

Materials and methods

Human Tca8113 and CAL-27 tongue squamous carcinoma cell lines were treated with EVO and GEM in different sequences and doses, after which cell proliferation was measured. Drug interactions were analyzed using the Chou–Talalay method with CompuSyn software. Clonality, apoptosis, and migration were measured using the plate clone formation assay, annexin V/propidium iodide (PI) staining, Hoechst 33342 staining, and the wound-healing test. The activity of the nuclear factor kappa light-chain enhancer of activated B cell (NF-κB) p65 subunit and its downstream proteins was quantified by Western blotting. The effects of the drug combination in vivo were assessed using a CAL-27 heterotopic xenograft model.

Results

EVO and GEM had synergistic effects on CAL-27 and Tca8113 cell lines in time- and concentration-dependent manners. Combination of drugs inhibited cell proliferation and migration and reduced the expression of NF-κB p65, B cell lymphoma 2 (Bcl-2), and B cell lymphoma extra large (Bcl-xl) compared with the control and either drug alone. In vivo, combination treatment of the xenograft model with EVO and GEM led to a significant reduction in tumor volume growth and inhibited the activation of NF-κB p65 with no obvious adverse reactions.

Conclusion

The results of this study showed that EVO may inhibit cancer cells by suppressing NF-κB activity, and in combination with GEM, it may increase the chemosensitivity of tongue squamous cancer cells, thereby improving the treatment response.

Inactivation of RUNX3 protein expression in tongue squamous cell carcinoma and its association with clinicopathological characteristics

The function of runt-related transcription factor 3 (RUNX3) in oral cancer remains controversial. The present study aimed to determine the status of RUNX3 protein expression and its association with clinicopathological characteristics in tongue squamous cell carcinomas (SCC). The present study used three pairs of tongue SCC and non-cancerous tissues to assess RUNX3 protein expression by western blot analysis, and two tongue SCC cell lines to determine RUNX3 protein localization by immunofluorescence and immunocytochemistry. Tissue microarray immunohistochemistry was performed to detect the clinical relevance of RUNX3 in 79 patients with tongue SCC. The results demonstrated that RUNX3 protein expression was reduced in tongue SCC tissues compared with in paired non-cancerous tissues. Similarly, the expression of RUNX3 was low in SCC25 and Cal27 cells, and was predominantly localized to the cytoplasm. In the 79 patients with tongue SCC, RUNX3 protein expression was presented in different manners in carcinoma nests and tumor stroma. RUNX3 in carcinoma nests (nRUNX3) exhibited nuclear positive staining in 24/79 samples, cytoplasmic mislocalization in 41/79 samples and was undetectable in 14/79 samples. RUNX3 in stroma (sRUNX3) exhibited nuclear positive staining in 40/79 samples and nuclear negative staining in 39/79 samples. Negative nRUNX3 expression was significantly associated with lymph node metastasis (P=0.014), clinical stage (P=0.027), and overall and disease-free survival (P=0.008 and P=0.007, respectively). In addition, negative sRUNX3 expression was associated with lymph node metastasis (P=0.003) and clinical stage (P=0.003); however, not with overall survival. The findings of the present study preliminarily suggested that cytoplasmic mislocalization of RUNX3 protein may be a common event in tongue SCC, and that sRUNX3 protein expression may be a potential prognostic biomarker.

Interleukin-18 expression in oral squamous cell carcinoma: its role in tumor cell migration and invasion, and growth of tumor cell xenografts

Oral squamous cell carcinoma (OSCC) is one of the most common head and neck malignancies. Advanced stages of the disease are associated with poor survival, highlighting a need for new treatment modalities. We previously showed that the proinflammatory cytokine interleukin‐18 (IL‐18) has a tumor suppressive role in OSCC. Here, we investigated the effects of IL‐18 on proliferation, migration, and invasion of OSCC cells ex vivo and in vitro, and in nude mouse xenografts. We report that expression of tankyrase 2 (TNKS2), β‐catenin, and N‐cadherin was higher in tumor cells than in normal mucosae, whereas the expression of IL‐18 and E‐cadherin was higher in normal than in tumor tissues. Elevated expression of IL‐18 (P < 0.01) and E‐cadherin (P = 0.034) was associated with tumor differentiation, whereas expression of TNKS2 (P < 0.01), β‐catenin (P = 0.012), and N‐cadherin (P < 0.01) was associated with tumor de‐differentiation. Furthermore, compared with the vector control, IL‐18 overexpression promoted tumor cell migration and invasion (P < 0.01), but inhibited growth of tumor cell xenografts (P < 0.05). At the protein level, expression levels of IL‐18 (P < 0.01), TNKS2 (P = 0.045), β‐catenin (P = 0.028), and N‐cadherin (P = 0.068) were upregulated in tumor cells after IL‐18 overexpression compared with those of the vector control mice, whereas expression levels of E‐cadherin (P = 0.045) were decreased. In conclusion, our data suggest that IL‐18 overexpression induces oral SCC cell invasion and metastasis by promoting the tumor cell epithelial–mesenchymal transition via the Wnt/β‐catenin signaling pathway.

MicroRNA-342-3p functions as a tumor suppressor by targeting LIM and SH3 protein 1 in oral squamous cell carcinoma

Although microRNA-342-3p (miR-342-3p) deregulation has been implicated in the development of a variety of cancer types, its role in oral squamous cell carcinoma (OSCC) progression remains unclear. Overexpression of LIM and SH3 protein 1 (LASP1) in OSCC tissues, and its promotion of OSCC cell proliferation were recently reported. However, the regulatory mechanism underlining LASP1 expression remains unknown. In the present study, the notable downregulation of miR-342-3p in OSCC cell lines and clinical specimens was revealed. The Cell Counting kit-8 and 5-bromo-2-deoxyuridine-incorporation assays demonstrated that miR-342-3p suppressed OSCC cell proliferation. Additionally, LASP1 was identified as a target gene of miR-342-3p through bioinformatics analysis and luciferase reporter assays. Further experiments suggested that overexpression of LASP1 attenuated the suppressive effect of miR-342-3p on the proliferation of OSCC cells. In conclusion, the present data suggest that miR-342-3p functions as a tumor suppressor in OSCC via targeting of LASP1 and may be a promising therapeutic target for OSCC.

Insights into the human oral microbiome

Human oral cavity harbors the second most abundant microbiota after the gastrointestinal tract. The expanded Human Oral Microbiome Database (eHOMD) that was last updated on November 22, 2017, contains the information of approximately 772 prokaryotic species, where 70% is cultivable, and 30% belong to the uncultivable class of microorganisms along with whole genome sequences of 482 taxa. Out of 70% culturable species, 57% have already been assigned to their names. The 16S rDNA profiling of the healthy oral cavity categorized the inhabitant bacteria into six broad phyla, viz. Firmicutes, Actinobacteria, Proteobacteria, Fusobacteria, Bacteroidetes and Spirochaetes constituting 96% of total oral bacteria. These hidden oral micro-inhabitants exhibit a direct influence on human health, from host's metabolism to immune responses. Altered oral microflora has been observed in several diseases such as diabetes, bacteremia, endocarditis, cancer, autoimmune disease and preterm births. Therefore, it becomes crucial to understand the oral microbial diversity and how it fluctuates under diseased/perturbed conditions. Advances in metagenomics and next-generation sequencing techniques generate rapid sequences and provide extensive information of inhabitant microorganisms of a niche. Thus, the retrieved information can be utilized for developing microbiome-based biomarkers for their use in early diagnosis of oral and associated diseases. Besides, several apex companies have shown keen interest in oral microbiome for its diagnostic and therapeutic potential indicating a vast market opportunity. This review gives an insight of various associated aspects of the human oral microbiome.

Screening pathogenic genes in oral squamous cell carcinoma based on the mRNA expression microarray data

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies and its survival rate has barely improved over the past few decades. The purpose of this study was to screen pathogenic genes of OSCC via microarray analysis. The mRNA expression microarray datasets (GSE2280 and GSE3524) were downloaded from the Gene Expression Omnibus (GEO) database. In GSE2280, there were 22 OSCC samples without metastasis and 5 OSCC samples with lymph node metastasis. In GSE3524, there were 16 OSCC samples and 4 normal tissue samples. The differentially expressed genes (DEGs) in OSCC samples with lymph node metastasis compared with those without metastasis (named as DEGs-1), and the DEGs in OSCC samples compared with normal tissue samples (named as DEGs-2), were obtained via limma package. The Database for Annotation, Visualization and Integrated Discovery (DAVID) was used to perform the functional enrichment analyses of DEGs-1 and DEGs-2. The miRNA-gene pairs of overlaps among DEGs were screened out with the TargetScan database, and the miRNA-gene regulated network was constructed by Cytoscape software. A total of 233 and 410 DEGs were identified in the sets of DEGs-1 and DEGs-2, respectively. DEGs-1 were enriched in 188 Gene Ontology (GO) terms and 8 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and DEGs-2 were enriched in 228 GO terms and 6 KEGG pathways. In total, 126 nodes and 135 regulated pairs were involved in the miRNA-gene regulated network. Our study indicated that transglutaminase 2 (TGM2) and Islet 1 (ISL1) may be biomarkers of OSCC and their metastases. Moreover, it provided some potential pathogenic genes (e.g. P2RY2 and RAPGEFL1) in OSCC.

Hedgehog and TGFβ signaling converge on Gli2 to control bony invasion and bone destruction in oral squamous cell carcinoma

Oral Squamous Cell Carcinoma (OSCC) is the sixth most common cancer worldwide. OSCC invasion into the lymph nodes and mandible correlates with increased rates of recurrence and lower overall survival. Tumors that infiltrate mandibular bone proliferate rapidly and induce bone destruction. While survival rates have increased 12% over the last 20 years, this improvement is attributed to general advances in prevention, earlier detection, and updated treatments. Additionally, despite decades of research, the molecular mechanisms of OSCC invasion into the mandible are not well understood. Parathyroid Hormone-related Protein (PTHrP), has been shown to be essential for mandibular invasion in OSCC animal models, and our previous studies demonstrate that the transcription factor Gli2 increases PTHrP expression in tumor metastasis to bone. In OSCC, we investigated regulators of Gli2, including Hedgehog, TGFβ, and Wnt signaling to elucidate how PTHrP expression is controlled. Here we show that canonical Hedgehog and TGFβ signaling cooperate to increase PTHrP expression and mandibular invasion in a Gli2-dependent manner. Additionally, in an orthotopic model of mandibular invasion, inhibition of Gli2 using shRNA resulted in a significant decrease of both PTHrP expression and bony invasion. Collectively, our findings demonstrate that multiple signaling pathways converge on Gli2 to mediate PTHrP expression and bony invasion, highlighting Gli2 as a therapeutic target to prevent bony invasion in OSCC.

Metabolic Profile of Oral Squamous Carcinoma Cell Lines Relies on a Higher Demand of Lipid Metabolism in Metastatic Cells

Tumor cells are subjected to a broad range of selective pressures. As a result of the imposed stress, subpopulations of surviving cells exhibit individual biochemical phenotypes that reflect metabolic reprograming. The present work aimed at investigating metabolic parameters of cells displaying increasing degrees of metastatic potential. The metabolites present in cell extracts fraction of tongue fibroblasts and of cell lines derived from human tongue squamous cell carcinoma lineages displaying increasing metastatic potential (SCC9 ZsG, LN1 and LN2) were analyzed by ¹H NMR (nuclear magnetic resonance) spectroscopy. Living, intact cells were also examined by the non-invasive method of fluorescence lifetime imaging microscopy (FLIM) based on the auto fluorescence of endogenous NADH. The cell lines reproducibly exhibited distinct metabolic profiles confirmed by Partial Least-Square Discriminant Analysis (PLS-DA) of the spectra. Measurement of endogenous free and bound NAD(P)H relative concentrations in the intact cell lines showed that ZsG and LN1 cells displayed high heterogeneity in the energy metabolism, indicating that the cells would oscillate between glycolysis and oxidative metabolism depending on the microenvironment’s composition. However, LN2 cells appeared to have more contributions to the oxidative status, displaying a lower NAD(P)H free/bound ratio. Functional experiments of energy metabolism, mitochondrial physiology, and proliferation assays revealed that all lineages exhibited similar energy features, although resorting to different bioenergetics strategies to face metabolic demands. These differentiated functions may also promote metastasis. We propose that lipid metabolism is related to the increased invasiveness as a result of the accumulation of malonate, methyl malonic acid, n-acetyl and unsaturated fatty acids (CH₂)_n in parallel with the metastatic potential progression, thus suggesting that the NAD(P)H reflected the lipid catabolic/anabolic pathways.

Epigenetic regulation of integrin β6 transcription induced by TGF-β1 in human oral squamous cell carcinoma cells

Overexpression of integrin αvβ6 is believed to play an important role in the invasion and metastasis of oral squamous cell carcinoma (OSCC). However, little is known about the molecular mechanisms leading to αvβ6 upregulation in OSCC. As the integrin β6 (ITGB6) is the only partner with αv, the expression of αvβ6 is dependent on ITGB6, it is, therefore, pivotal to investigate the mechanisms underlying ITGB6 overexpression in OSCC. We previously reported the cloning and characterization of human ITGB6 gene. In the current study, we further investigated the molecular mechanisms of ITGB6 expression and the upregulation by carcinogenesis related cytokine-transforming growth factor-β1 (TGF-β1) in OSCC cells. We first demonstrated that TGF-β1 can induce ITGB6 mRNA and protein express in a time and concentration dependent manner, and the induced-ITGB6 mRNA was not due to increase the mRNA stability, but regulated at transcriptional level. By using a luciferase reporter assay, site-mutation, RNA interference, and chromatin immunoprecipitation assay, we revealed for the first time that JunB, a member of the activator protein-1 (AP-1) family, is involved in the positive regulation to the ITGB6 transcription induced by TGF-β1 in OSCC cells. Furthermore, our data also demonstrated that histone acetyltransferase (HAT) CBP mediated histone H3 and H4 hyperacetylation, and RNA Polymerase II recruitment to ITGB6 promoter, facilitated the binding of transcription factor JunB to ITGB6 promoter after TGF-β1 stimulation. Collectively, these findings demonstrate that JunB and CBP-mediated histone hyperacetylation are responsible for TGF-β1 induced ITGB6 transcription in OSCC cells, suggesting that epigenetic mechanisms are responsible for the active transcription expression of ITGB6 induced by TGF-β1 in OSCC cells.

Evaluation of glutathione peroxidase in the blood and tumor tissue of oral squamous cell carcinoma patients

Aims and Objectives:

The lowered antioxidant capacity and the oxidant–antioxidant imbalance have been considered to play a role in multistage carcinogenesis. The deleterious effects produced by reactive oxygen species depend on the imbalance between oxidant and antioxidant status in the body, so this study is aimed to evaluate the levels of antioxidant enzyme, glutathione peroxidase (GPx), in the blood and tumor tissues of oral squamous cell carcinoma (OSCC) patients in comparison with healthy controls.

Materials and Methods:

The study comprised of 38 participants divided into two groups. Group 1 comprised of 20 patients with OSCC and Group 2 comprised of age- and sex-matched 18 healthy individuals free of any habits and systemic illness. The levels of GPx were estimated in the blood and tissue samples in both groups by Paglia and Valentine method using a Commercial Biochemical assay kit (RANDOX), by ultraviolet-visible spectrophotometer.

Results:

The GPx levels were elevated in the whole blood and the tissue samples of OSCC cases as compared to the control group. It was also found that the GPx levels were increased in the tumor tissue with respect to the histopathological grading of the OSCC cases.

Conclusion:

Detection of antioxidant status may be useful to choose correct radiotherapy or chemotherapy, to monitor the effectiveness of the therapeutic strategy and to determine tumor resistance to therapy. Hence, the evaluation of GPx enzyme level can be used as a prognostic marker in patients with OSCC.

Effects of Damnacanthal and Nordamnacanthal on Proliferation, Apoptosis, and Migration of Oral Squamous Cell Carcinoma Cells

Cancer is one of the most common causes of death in the developed world, with one-third of people diagnosed with cancer during their lifetime. Oral cancer commonly occurs involving the buccal mucosa (cheeks), tongue, floor of the mouth and lip. It is one of the most devastating and disfiguring of malignancies. Morinda citrifolia L., commonly known as ‘noni’, belongs to the Rubiaceae family. It is native to the Pacific islands, Hawaii, Caribbean, Asia and Australia. The plant displays broad curative effects in pharmacological studies. Damnacanthal (DAM) and Nordamnacanthal (NDAM), anthraquinone compounds isolated from the roots of Morinda citrifolia L., has been used for the treatment of several chronic diseases including cancer. The objectives of this study were to evaluate cytotoxicity, morphological changes, cell death mode (apoptosis/necrosis), and cell migration induced by DAM and NDAM on the most common type of oral cancer, oral squamous cell carcinoma (OSCC)cells. Anti-proliferative effects of these compounds against OSCC cell lines were determined by MTT assay. The mode of cell death was analysed by phase contrast and fluorescent microscopy as well as flow cytometry. In addition, cell migration was assessed. The results showed that DAM and NDAM exerted cytotoxicity against OSCC cells with IC₅₀ values of 1.9 to >30 μg/ml after 72 h treatment. Maximum growth inhibition among the tested cell lines for both compounds was observed in H400 cells, and thus it was selected for further study. The study demonstrated inhibition of H400 OSCC cell proliferation, marked apoptotic morphological changes, induction of early apoptosis, and inhibition of cell migration by DAM and NDAM. Therefore, this information suggests that these compounds from noni have potential for used as anti tumor agents for oral cancer therapy.

Analysis of the Epithelium-Mesenchymal Transition Process on Oral Squamous Cell Carcinomas

The aim of this study is to evaluate the immunohistochemical expression of E-cadherin, N-cadherin and Bmi-1, and their association with clinical parameters and with the degree of histopathological differentiation in oral squamous cell carcinomas. 65 squamous cell carcinoma samples were used for constructing a tissue microarray block, and then immunohistochemistry was performed for different markers. A semi-quantitative analysis of the amount of positive tumor cells was performed by two blind and calibrated observers (Kappa>0.75). The statistical Mann-Whitney and Kruskal-Wallis tests were used to evaluate the data. The correlation between variables was investigated by the Spearman test, and the significance level set at p<0.05. We observed higher expression of Bmi-1 in tumors located in the palate (p<0.0001). In addition, poorly differentiated tumors had a greater amount of Bmi-1 positive cells (p=0.0011). Regarding the other correlations between variables, no significant associations were detected. In conclusion, poorly differentiated squamous cell carcinomas located in the palate have higher immunostaining of Bmi-1, which can characterize activation of the Epithelial-Mesenchymal Transition process in these tumors.

Elevated autocrine chemokine ligand 18 expression promotes oral cancer cell growth and invasion via Akt activation

Chemokine (C-C motif) ligand 18 (CCL18) has been implicated in the pathogenesis and progression of various cancers; however, in oral squamous cell carcinoma (OSCC), the role of CCL18 is unknown. In this study, we found that CCL18 was overexpressed in primary OSCC tissues and was associated with an advanced clinical stage. CCL18 was found in both the cytoplasm and cell membrane of OSCC cells and was predominantly produced by cancer epithelial cells, as opposed to tumor-infiltrating macrophages. In vitro studies indicated that the effects of endogenous CCL18 on OSCC cell growth, migration, and invasion could be blocked by treatment with a neutralizing anti-CCL18 antibody or CCL18 knockdown, while exogenous recombinant CCL18 (rCCL18) rescued those effects. Akt was activated in rCCL18-treated OSCC cells, while LY294002, a pan-PI3K inhibitor, abolished both endogenous and exogenous CCL18-induced OSCC cell invasion. In vivo, LY294002 treatment attenuated rCCL18-induced OSCC cell growth. Our results indicate that CCL18 acts in an autocrine manner via Akt activation to stimulate OSCC cell growth and invasion during OSCC progression. They also provide a potential therapeutic target for the treatment of oral cancer.

The Microbiome of Potentially Malignant Oral Leukoplakia Exhibits Enrichment for Fusobacterium, Leptotrichia, Campylobacter, and Rothia Species

Oral leukoplakia presents as a white patch on the oral mucosa and is recognized as having significant malignant potential. Although colonization of these patches with Candida albicans is common, little is known about the bacterial microbiota of these patches. In the current study we analyzed the microbiome of oral leukoplakia in 36 patients compared to healthy mucosal tissue from the same patients and healthy control subjects to determine if specific microbial enrichments could be identified early in the malignant process that could play a role in the progression of the disease. This was carried out by sequence analysis of the V1–V2 region of the bacterial 16S rRNA gene using the Illumina MiSeq. Oral leukoplakia exhibited increased abundance of Fusobacteria and reduced levels of Firmicutes (Metastats P < 0.01). Candida colonization was also more prevalent in leukoplakia patients relative to healthy controls (P = 0.025). Bacterial colonization patterns on oral leukoplakia were highly variable and five distinct bacterial clusters were discerned. These clusters exhibited co-occurrence of Fusobacterium, Leptotrichia, and Campylobacter species (Pearson P < 0.01), which is strikingly similar to the microbial co-occurrence patterns observed on colorectal cancers (Warren et al., 2013). Increased abundance of the acetaldehydogenic microorganism Rothia mucilaginosa was also apparent on oral leukoplakias from lingual sites (P 0.0012). Severe dysplasia was associated with elevated levels of Leptotrichia spp. and Campylobacter concisus (P < 0.05). Oral leukoplakia exhibits an altered microbiota that has similarities to the microbiome of colorectal cancer.

White oral mucosal lesions among the Yemeni population and their relation to local oral habits

AIMS

The aim of the present study was to assess the prevalence and risk factors of white oral mucosal lesions among Yemeni adults; in particular, those who chew khat and tobacco.

METHODS

The present cross-sectional study included 1052 dental patients aged 15 years and older. A detailed oral examination was performed by a single examiner in accordance with standard international criteria.

RESULTS

Overall, 25.2% of the study participants presented with one or more white lesions. The most prevalent lesions were khat-induced white lesion (8.8%), leukoedema (5.1%), and frictional keratosis (3.9%). Potentially malignant lesions, such as lichen planus, leukoplakia, and smokeless tobacco-induced lesions, were seen in 2.4%, 1.2%, and 1.7% of participants, respectively. Moreover, three cases of oral cancer were identified. The presence of white lesions was found to be significantly associated with advanced age (P = .004), male gender (P = .009), and khat/tobacco chewing habits (P < .001).

CONCLUSIONS

The present study demonstrates a high prevalence of oral benign and potentially malignant white lesions. Further, it highlights the urgent need to develop and implement new government policies to regulate the sale of these products to reduce the prevalence of these lesions and the overall incidence of oral cancers in the Yemeni population.

Prognostic Prediction of Oral Squamous Cell Carcinoma by E-Cadherin and N-Cadherin Expression in Overall Cells in Tumor Nests or Tumor Cells at the Invasive Front

Epithelial-mesenchymal transition (EMT) is a significant process in the invasion and metastasis of cancers including oral squamous cell carcinoma (OSCC), and the cadherin switch has been identified as one of the hallmarks of EMT. The aim of the present study was to evaluate the significance of the cadherin switch in the prognosis of OSCC and generate a model for prognostic predictions. Seventy-six biopsy and/or initial surgical specimens from OSCC patients were immunohistochemically analyzed for the expression of E-cadherin and N-cadherin in either overall OSCC cells in tumor nests or in OSCC cells at the invasive front. Among 76 OSCC cases, overall OSCC cells in tumor nests were negative for the expression of E-cadherin in 10 cases and positive for that of N-cadherin in 53 cases. Among 10 cases negative for the expression of E-cadherin, 4 cases were positive for that of N-cadherin. In OSCC cells at the invasive front, the expression of E-cadherin was negative in 62 cases, while that of N-cadherin was positive in 39 cases. Among 62 cases negative for the expression of E-cadherin, 33 cases were positive for that of N-cadherin. A logistic regression analysis showed that a model using the evaluation of N-cadherin expression in overall OSCC cells in tumor nests with a cut-off point of 70 years old was the best fit model. These results suggest that N-cadherin has significant value in prognostic predictions for OSCC patients.

Oral Cancer Knowledge and Diagnostic Ability Among Dental Students

The purpose of this study is to examine factors that influence the diagnostic ability of dental students with regards to oral cancer and oral potentially malignant disorders. Dental students at different levels of study were directly interviewed to examine their oral cancer knowledge and diagnostic ability using a validated and pre-tested survey instrument containing validated clinical images of oral cancer and oral potentially malignant disorders. An oral cancer knowledge scale (0 to 31) was generated from correct responses on oral cancer general knowledge, and a diagnostic ability scale (0 to 100) was generated from correct selections of suspicious oral lesions. Knowledge scores ranged from 0 to 27 (mean 10.1 ± 6.0); mean knowledge scores increased with year of study; 5th year students had the highest mean knowledge score (19.1 ± 4.0), while 1st year students had the lowest (5.6 ± 3.5). Diagnostic ability scores increased with year of study and ranged from 0 to 88.5 % (mean 41.8 % ± 15.6). The ability to recognize suspicious oral lesions was significantly correlated with knowledge about oral cancer and oral potentially malignant disorders (r = 0.28; P < 0.001). There is a need to improve oral cancer education curricula; increasing students' contact with patients who have oral lesions including oral cancer will help to improve their future diagnostic ability and early detection practices.

Effect of TET1 regulating MGMT on chemotherapy resistance of oral squamous cell carcinoma stem cells

The study was to evaluate the effect of ten-eleven translocation 1 (TET1) regulating o6-methylguanine-DNA methyltransferase (MGMT) in chemotherapy resistance of oral squamous cell carcinoma (OSCC) stem cells. OSCC stem cells were divided into the blank, negative control (NC), TET1-siRNA, TET1-siRNA + MGMT-OE, and MGMT-OE groups. Methylation-specific polymerase chain reaction (MSP), qRT-PCR and Western blotting were conducted to detect the methylation status of MGMT, expressions of TET1, MGMT, ABCG2, and Oct-4. Cell proliferation, cisplatin chemosensitivity, and cell cycle and apoptosis, were detected using CCK8 and flow cytometry. A chromatin immunoprecipitation (ChIP) assay was employed for detecting the link between TET1 and MGMT gene promoters. In comparison to the NC group, the TET1-siRNA group exhibited increased levels of MGMT methylation, the number of apoptotic cells and cisplatin chemosensitivity consisting of varying concentrations, however, decreased levels of mRNA and protein expressions of TET1 as well as MGMT, cell viability, the number of cells in the S phase, and protein expressions of ABCG2 and Oct-4 were all have diminished amounts. The TET1-siRNA + MGMT-OE and MGMT-OE groups had higher MGMT mRNA and protein expression, as well as increased protein expressions of ABCG2 and Oct-4, greater cell activity, higher number of cells in the S phase, decreased apoptotic rates in cells and decreased cisplatin chemosensitivity with different concentrations. Our study provided evidence that low-expression of TET1 in OSCC stem cells may stimulate MGMT promoter methylation, while inhibiting MGMT mRNA expression, this ultimately strengthens the sensitivity of OSCC stem cells in regards to chemotherapeutics.

Chemokine (CC motif) ligand 18 upregulates Slug expression to promote stem-cell like features by activating the mammalian target of rapamycin pathway in oral squamous cell carcinoma

Chemokine (CC motif) ligand 18 (CCL18) is involved in remodeling of the tumor microenvironment and plays critical roles in oncogenesis, invasiveness, and metastasis. We previously investigated the overexpression of CCL18 in primary oral squamous cell carcinoma (OSCC) tissues and its association with advanced clinical stage in OSCC patients. However, the underlying mechanisms of this CCL18‐derived activity remains unidentified. This study showed exogenous CCL18 increased cell migration and invasion and induced cell epithelial–mesenchymal transition (EMT), and that E‐cadherin, an epithelial marker, decreased and N‐cadherin, a mesenchymal marker, increased, compared to negative control in OSCC cells. Furthermore, we detected that CCL18 induced the acquisition of cancer stem(‐like) cell characteristics in oral cancer cells, but also found a significantly positive correlation between the expression of CCL18 and Bmi‐1 (P < 0.001) in OSCC surgical specimens by immunohistochemistry analysis. The expression of octamer‐binding transcription factor 4 and Bmi‐1 were significantly upregulated, and proportions of aldehyde dehydrogenase^high+ cells and CD133⁺ cells were markedly increased in CCL18‐treated cells compared to untreated cells. Sphere formation ability was observably enhanced when cells were continually exposed to high levels of CCL18. Moreover, CCL18 upregulated Slug expression by stimulating the mammalian target of rapamycin (mTOR) signaling pathway in OSCC cell lines. Inhibition of the mTOR pathway by INK128, or Slug knockdown by RNA interference, reversed CCL18‐induced EMT and the stemness response at both molecular and functional levels. In conclusion, our data suggested that CCL18 upregulated Slug expression to promote EMT and stem cell‐like features by activating the mTOR pathway in oral cancer. These findings provide new potential targets for the early diagnosis and treatment of OSCC.

Concomitant-chemoradiotherapy-associated oral lesions in patients with oral squamous-cell carcinoma

OBJECTIVE

: Oral squamous-cell carcinoma (OSCC) accounts for >90% of oral cancers affecting adults mostly between the fourth to seventh decades of life. The most common OSCC treatment is concomitant chemoradiotherapy (CCRT) having both loco-regional and distant control, but CCRT has acute and chronic toxic effects on adjacent normal tissue. This study aimed to determine the side effects of CCRT on the oral mucosa and to characterize the clinicopathology of oral lesions in patients with OSCC.

METHODS

This descriptive, cross-sectional study was certified by the Ethical Review Committee (UHS/Education/126-12/2728) of the University of Health Sciences, Lahore, Pakistan. OSSC patients (n=81) with various histological subtypes, grades, and stages were recruited, and findings on their oral examination were recorded. These patients received 70, 90, and 119 Gy of radiotherapy dosages in combination with the chemotherapy drugs cisplatin and 5-fluorouracil. Data were analyzed using SPSS 20.0.

RESULTS

: The most common presentation of OSCC was a nonhealing ulcer (63%) involving tongue (55.6%). Clinical findings included mucositis (92.6%) and xerostomia of mild, moderate, and severe degrees in 11.1%, 46.9%, and 35.8% cases, respectively. Ulcers (87.7%), palpable lymph nodes (64.2%), limited mouth opening (64.2%) and fistula (40.7%) were also observed. In females, the association of radiotherapy dosage with limited mouth opening, xerostomia, and histological grading was statistically significant (P<0.05). The association of chemotherapy drugs with xerostomia (P=0.003) was also statistically significant.

CONCLUSIONS

: CCRT induced mucositis, xerostomia, and trismus in patients with OSCC.

Detection of Human Papillomavirus 16-Specific IgG and IgM Antibodies in Patient Sera: A Potential Indicator of Oral Squamous Cell Carcinoma Risk Factor

The association between human papillomavirus type 16 (HPV16) and oral cancer has been widely reported. However, detecting anti-HPV antibodies in patient sera to determine risk for oral squamous cell carcinoma (OSCC) has not been well studied. In the present investigation, a total of 206 OSCC serum samples from the Malaysian Oral Cancer Database & Tissue Bank System, with 134 control serum samples, were analyzed by enzyme-linked immunosorbant assay (ELISA) to detect HPV16-specific IgG and IgM antibodies. In addition, nested PCR analysis using comprehensive consensus primers (PGMY09/11 and GP5(+)/6(+)) was used to confirm the presence of HPV. Furthermore, we have evaluated the association of various additional causal factors (e.g., smoking, alcohol consumption, and betel quid chewing) in HPV-infected OSCC patients. Statistical analysis of the Malaysian population indicated that OSCC was more prevalent in female Indian patients that practices betel quid chewing. ELISA revealed that HPV16 IgG, which demonstrates past exposure, could be detected in 197 (95.6%) OSCC patients and HPV16-specific IgM was found in a total of 42 (20.4%) OSCC patients, indicating current exposure. Taken together, our study suggest that HPV infection may play a significant role in OSCC (OR: 13.6; 95% CI: 3.89-47.51) and HPV16-specific IgG and IgM antibodies could represent a significant indicator of risk factors in OSCC patients.

Mucoepidermoid Carcinoma of the Palatine Tonsil

Mucoepidermoid carcinoma (MEC) is the most common primary salivary gland malignancy in both adults and children. It has a slight female predilection and usually presents as a painless, rubber-like or soft mass, which may be fixed or mobile. Histologically, MEC is comprised of a mixture of cell types including mucous, epidermoid, and intermediate cells that can be arranged in solid nests or cystic structures. In the oral cavity, it most frequently occurs at the palate or buccal mucosa. The present paper aimed to describe an unusual case of MEC arising in the palatine tonsil.

A Tetrameric Peptide Derived from Bovine Lactoferricin Exhibits Specific Cytotoxic Effects against Oral Squamous-Cell Carcinoma Cell Lines

Several short linear peptides derived from cyclic bovine lactoferricin were synthesized and tested for their cytotoxic effect against the oral cavity squamous-cell carcinoma (OSCC) cell lines CAL27 and SCC15. As a control, an immortalized and nontumorigenic cell line, Het-1A, was used. Linear peptides based on the RRWQWR core sequence showed a moderate cytotoxic effect and specificity towards tumorigenic cells. A tetrameric peptide, LfcinB(20–25)₄, containing the RRWQWR motif, exhibited greater cytotoxic activity (>90%) in both OSCC cell lines compared to the linear lactoferricin peptide or the lactoferrin protein. Additionally, this tetrameric peptide showed the highest specificity towards tumorigenic cells among the tested peptides. Interestingly, this effect was very fast, with cell shrinkage, severe damage to cell membrane permeability, and lysis within one hour of treatment. Our results are consistent with a necrotic effect rather than an apoptotic one and suggest that this tetrameric peptide could be considered as a new candidate for the therapeutic treatment of OSCC.

How many individuals must be screened to reduce oral cancer mortality rate in the Western context? A challenge

OBJECTIVE

Controlling oral cancer (OC) through screening is appealing. Advantages of this are as follows: OC is often preceded by visible premalignant lesions, early-stage survival is threefold greater than late-stage survival, and visual screening is inexpensive. Disadvantages of this are as follows: high frequency of false positives, undemonstrated cost-effectiveness, and irregular screening attendance by high-risk individuals. Screening effectiveness in Western countries has not been proven, because of low OC prevalence, which disproportionally increases the number of individuals needed to screen (NNS) to decrease mortality. This study estimated the NNS to obtain an evident decrease in OC mortality rate in the UK.

METHODS

Data gathered from reliable databanks were used. NNS to detect one case (NNScase ) was estimated using a Bayesian approach. NNS to prevent one death (NNSdeath ) was assessed multiplying NNScase by the number of cases that must be screen-detected to prevent one death. NNS to decrease mortality rate by 1% (NNSmortality ) was assessed multiplying NNSdeath by 1% of annual OC deaths.

RESULTS

NNSmortality was overall 1 125 000 (95% confidence interval - 95CI, 690 000-1 870 000), males 551 000 (95CI, 337 000-916 000), and females 571 000 (95CI, 347 000-942 000).

CONCLUSIONS

An OC visual screening campaign capable of producing an evident decrease in mortality rate in the UK requires a large number of adults to be annually and regularly screened.