Advances and applications of oral cancer basic research

Monitoring carcinogenesis in a case of oral squamous cell carcinoma using a panel of new metabolic blood biomarkers as liquid biopsies

INTRODUCTION

One of the common malignant tumors of the head and neck worldwide with generally unfavorable prognosis is squamous cell carcinoma (OSCC) of the oral cavity. Early detection of primary, secondary, or recurrent OSCC by liquid biopsy tools is much needed.

CASE PRESENTATION

Twelve blood biomarkers were used for monitoring a case of OSCC suffering from precancerous oral lichen ruber planus mucosae (OLP). After curative R0 tumor resection of primary OSCC (buccal mucosa), elevated epitope detection in monocytes (EDIM)-Apo10, EDIM-transketolase-like-1 (TKTL1), squamous cell carcinoma antigen (SCC-Ag), total serum lactate dehydrogenase (LDH), and its anaerobic isoforms (LDH-4, LDH-5) decreased to normal levels. Three and six months after surgery, transformation of suspicious mucosal lesions has been accompanied with an increase of EDIM scores, total serum LDH values, and a metabolic shift from aerobic (decrease of LDH-1, LDH-2) to anaerobic (increase of LDH-4, LDH-5) conditions. Two months later, secondary OSCC was histopathologically analyzed after tissue biopsy. Cytokeratin fraction 21-1 (CYFRA 21-1), carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9) were not affected during the clinical course of carcinogenesis.

CONCLUSIONS

A combination strategy using a standardized panel of established (metabolic) blood biomarkers (TKTL1, LDH, LDH isoenzymes) is worth and can be recommended among others (apoptosis resistance-related Apo10, SCC-Ag) for early detection and diagnosis of primary, secondary, and recurrent OSCC. A tandem strategy utilizing (metabolic pronounced) routine liquid biopsies with imaging techniques may enhance diagnosis of OSCC in the future. Although we demonstrated the diagnostic utility of separated liquid biopsies in our previous study cohorts, further investigations in a larger patient cohort are necessary to recommend this combination strategy (EDIM blood test, LDH value, metabolic shift of LDH isoenzymes, and others, e.g., SCC-Ag or immunophenotyping) as a diagnostic tool for the addition to the OSCC staging system and as a routine procedure in the aftercare.

Gelsolin rs1078305 and rs10818524 polymorphisms were associated with risk of oral squamous cell carcinoma in a Chinese Han population

BACKGROUND

Gelsolin (GSN) is one of the most abundant actin-binding proteins, and is involved in cancer development and progression.

PATIENTS AND METHODS

A hospital-based case-control study including 201 patients with OSCC and 199 healthy controls was conducted. Seventeen single-nucleotide polymorphisms (SNPs) of GSN were investigated by Sequenom Mass ARRAY and iPLEX-MALDI-TOF technology.

RESULTS

Through comparison of the 17 SNPs on GSN gene between the two groups, SNP rs1078305 and rs10818524 were verified to be significantly associated with an increased risk of OSCC. For GSN rs1078305, the TT genotype was associated with increased risk for OSCC (OR = 1.92, 95% CI = 1.11-3.32, p = 0.028). CT/TT variants were also associated with increased risk for OSCC compared to the CC genotype (OR = 1.83, 95% CI = 1.25-3.84, p = 0.032).

CONCLUSION

The rs1078305 and rs10818524 SNPs of GSN were associated with increased risk for OSCC development in a Chinese Han population.

Association of the XPD and XRCC3 gene polymorphisms with oral squamous cell carcinoma in a Northeastern Brazilian population: A pilot study

OBJECTIVE

to evaluate the association between XPD and XRCC3 polymorphisms and oral squamous cell carcinoma (OSCC).

DESIGN

the sample consisted of 54 cases of OSCC and 40 cases of inflammatory fibrous hyperplasia (IFH). Genotypes were determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

XPD-Lys/Gln was more common in IFH (n=28; 70%) than in OSCC (n=24; 44.4%) (OR: 0.3; p<0.05). XPD-Gln was more frequent in high-grade lesions (0.48) than in low-grade lesions (0.21) (OR: 3.4; p<0.05). The Gln/Gln genotype was associated with III and IV clinical stages (OR: 0.07; p<0.05). XRCC3-Met was more frequent in OSCC (0.49) than in IFH (0.35) (OR: 2.6; p<0.05). The Met/Met genotype was associated with the presence of metastases (OR: 8.1; p<0.05) and with III and IV clinical stages (OR: 0.07; p<0.05).

CONCLUSIONS

in this sample, the frequency of XPD-Gln in IFH suggests that this variant may protect against OSCC. The presence of the XRCC3-Met allele seems to contribute to the development of OSCC, metastases and more advanced stages in these lesions.

A targeted proteomic strategy for the measurement of oral cancer candidate biomarkers in human saliva

Head and neck cancers, including oral squamous cell carcinoma (OSCC), are the sixth most common malignancy in the world and are characterized by poor prognosis and a low survival rate. Saliva is oral fluid with intimate contact with OSCC. Besides non-invasive, simple, and rapid to collect, saliva is a potential source of biomarkers. In this study, we build an SRM assay that targets fourteen OSCC candidate biomarker proteins, which were evaluated in a set of clinically-derived saliva samples. Using Skyline software package, we demonstrated a statistically significant higher abundance of the C1R, LCN2, SLPI, FAM49B, TAGLN2, CFB, C3, C4B, LRG1, SERPINA1 candidate biomarkers in the saliva of OSCC patients. Furthermore, our study also demonstrated that CFB, C3, C4B, SERPINA1 and LRG1 are associated with the risk of developing OSCC. Overall, this study successfully used targeted proteomics to measure in saliva a panel of biomarker candidates for OSCC.

Insights into immune responses in oral cancer through proteomic analysis of saliva and salivary extracellular vesicles

The development and progression of oral cavity squamous cell carcinoma (OSCC) involves complex cellular mechanisms that contribute to the low five-year survival rate of approximately 20% among diagnosed patients. However, the biological processes essential to tumor progression are not completely understood. Therefore, detecting alterations in the salivary proteome may assist in elucidating the cellular mechanisms modulated in OSCC and improve the clinical prognosis of the disease. The proteome of whole saliva and salivary extracellular vesicles (EVs) from patients with OSCC and healthy individuals were analyzed by LC-MS/MS and label-free protein quantification. Proteome data analysis was performed using statistical, machine learning and feature selection methods with additional functional annotation. Biological processes related to immune responses, peptidase inhibitor activity, iron coordination and protease binding were overrepresented in the group of differentially expressed proteins. Proteins related to the inflammatory system, transport of metals and cellular growth and proliferation were identified in the proteome of salivary EVs. The proteomics data were robust and could classify OSCC with 90% accuracy. The saliva proteome analysis revealed that immune processes are related to the presence of OSCC and indicate that proteomics data can contribute to determining OSCC prognosis.

MicroRNA-101 polymorphisms and risk of head and neck squamous cell carcinoma in a Chinese population

MicroRNAs (miRNAs) play important roles in regulation of gene expressions and likely have involvement in cancer susceptibility and disease progression. MicroRNA-101 (miR-101) has been well established as a tumor suppressor, and aberrant expression of miR-101 levels has been previously reported in different malignancies including head and neck squamous cell carcinoma (HNSCC). However, the role of single nucleotide polymorphisms (SNPs) of miR-101 in the susceptibility to HNSCC remains unclear. In this study, we genotyped 11 selected SNPs of the miR-101 genes (including miR-101-1 and miR-101-2) in a case-control study including 576 HNSCC cases and 1552 cancer-free controls. For the main effect analysis, none of the 11 selected SNPs was associated with HNSCC risk. However, in the stratification analysis by tumor sites, rs578481 and rs705509 in pri-miR-101-1 were significantly associated with risk of oral squamous cell carcinoma (OSCC) (rs578481: adjusted odds ratio (OR) = 1.19, 95 % confidence interval (CI) 1.01-1.39, P = 0.036; rs705509: adjusted OR = 0.85, 95 % CI 0.73-0.98, P = 0.030). Furthermore, combined analysis of the two SNPs revealed that subjects carrying the risk alleles of rs578481 and rs705509 had increased risk of OSCC in a dose-response manner (P trend = 0.022). Compared with subjects carrying "0-2" risk alleles, subjects carrying "3-4" risk alleles presented a 1.38-fold increased risk of OSCC. In conclusion, our findings suggested that the SNPs rs578481 and rs705509 locating in pri-miR-101-1 may play a role in genetic susceptibility to OSCC, which may improve our understanding of the potential contribution of miRNA SNPs to cancer pathogenesis.

Trends in the incidence of Oral and Pharyngeal Cancer (ICD00-14) in Guilan, North of Iran

AIM

This study sought to assess the incidence of oral and pharyngeal cancer based on ICD-10 in Guilan, Iran, from 2004 to 2009.

METHOD

This retrospective study assessed data collected from the Iranian cancer registries and publications. The rate, age-standardized incidence, type, and location of lesions according to ICD-10 were evaluated. Annual percent changes (APC) were estimated.

RESULTS

A total of 1533 head and neck cancers were recorded. Of them, 290 cases (185 males and 105 females) were identified with oral and pharyngeal carcinoma (ICD00-14) with a mean age of 58.92 ± 17.94 years. The most common type of cancer was oral squamous cell carcinoma (n = 156). Cancer of the oropharynx (ICD 06) and lips (ICD00) had high incidence. APC was 1.36%. ASR was 3.5 and 2.04 per 100 000 among males and females, respectively. The mean crude rate was 3.69 per 1 000 000.

CONCLUSION

In contrast to the global cancer statistics (ICD 00-14), Guilan showed lower incidence of oral and pharyngeal cancer during the understudy years. Oral squamous cell carcinoma was the most common type of cancer in this region.

β-Catenin Alterations in Squamous Cell Carcinoma of the Lip

This study aimed to investigate the correlation between β-catenin immunoexpression and histopathological grades of lower lip squamous cell carcinoma (LSCC). β-Catenin abnormal expression was found in 29% of the squamous cells of well differentiated LSCC, 63% of moderately differentiated and 86% of poorly differentiated, and therefor was significantly associated with histological grade (p=0.000). Nuclear β-catenin expression appeared in 5% of the cells and was also correlated with the histological grades (p=0.000). In 14.7% of the cells it was localized in the cytoplasm, again correlating with histology (p=0.002). According to this study the expression of β-catenin is an independent prognostic factor for histological grade and to the tumor differentiation. This appears to reflect a structural association and the role of β-catenin in tumor progression.

Daxx and TCF4 interaction links to oral squamous cell carcinoma growth by promoting cell cycle progression via induction of cyclin D1 expression

Objectives

Death domain-associated protein (Daxx) has been recently implicated as a positive factor in ovarian cancer and prostate cancer, but the role of Daxx in oral squamous cell carcinoma (OSCC) has never been addressed. Herein, we investigate the expression and function of Daxx in OSCC.

Materials and methods

RT-quantitative PCR, Western blotting, and immunohistochemistry were used to evaluation of the expression of Daxx in human OSCC cell lines and clinical surgical specimens. Short hairpin RNA targeting Daxx was transduced by lentivirus infection to knockdown the expression of Daxx in SAS and SCC25 cell lines, and the influence of this knockdown was evaluated by analyzing the growth and the cell cycle in transduced cells. Immunoprecipitation and sequential chromatin immunoprecipitation-quantitative PCR were used to analyze the associations between Daxx, TCF4, and cyclin D1 promoter. Xenograft tumor model was used to evaluate the in vivo tumorigenicity of Daxx in OSCC.

Results

Daxx mRNA and protein expression are elevated in several OSCC cell lines and human OSCC samples in comparison to those in normal tissue. We further find that depletion of Daxx decreases OSCC cell growth activity through G1 cell cycle arrest. Daxx silencing reduces cyclin D1 expression via a Daxx-TCF4 interaction, whereas the Daxx depletion-mediated G1 arrest can be relieved by ectopic expression of cyclin D1. Moreover, we show that in OSCC clinical samples, the expression of Daxx is significantly correlated with that of cyclin D1.

Conclusion

Our data demonstrate the importance of Daxx in regulation of cyclin D1 expression and provide the first evidence that Daxx exhibits tumor-promoting activity in OSCC.

Clinical relevance

Daxx plays an important role in malignant transformation of OSCC and may serves as a target for cancer prevention and treatment.

Evaluation of a biomarker based blood test for monitoring surgical resection of oral squamous cell carcinomas

INTRODUCTION

The potential use of determination of biomarkers in blood for the monitoring of surgical removal of oral squamous cell carcinomas (OSCC) was evaluated using the epitope detection in monocytes (EDIM) technology.

MATERIALS AND METHODS

In tumor specimen, elevated Apo10 and transketolase-like 1 (TKTL1) expression was analyzed by immunohistochemistry. Apo10 and TKTL1 biomarkers have been used prospectively for EDIM blood test in patients with primary and/or recurrent OSCC (n = 92) before surgery and after curative tumor resection (n = 45).

RESULTS

There were highly significant (p < 0.0001) correlations found between EDIM blood scores and the tissue expression of both biomarkers measured by immunohistochemistry (Apo10: n = 89/92, 97%; TKTL1: n = 90/92, 98%). EDIMApo10 and EDIM-TKTL1 scores were positive in 92% (EDIM-Apo10: n = 85/92) and 93% (EDIM-TKTL1: n = 86/92), respectively, in patients with OSCC before surgery. The combined score EDIM-Apo10/EDIM-TKTL1 increased significantly the detection rate of tumors to 97% (n = 89/92). After surgery, the EDIM-TKTL1 and EDIMApo10 scores significantly decreased in 75.6 and 86.7% of the patients (p < 0.0001), respectively, in the aftercare.

CONCLUSIONS

The correlation of TKTL1 and Apo10 immunohistochemistry with the blood test results indicates that the EDIM blood test could serve as a non-invasive diagnostic tool (liquid biopsy) to assess surgical removal of OSCC by determination of two biomarkers.

CLINICAL RELEVANCE

This is the first study that has been demonstrated a reliable and successful monitoring of OSCC cancer patients by a blood test. The specific and significant decrease of EDIM-TKTL1 and EDIM-Apo10 scores after surgery could serve as a new tool for monitoring surgical removal of OSCC.

Therapeutic Efficacy of Orally Delivered Doxorubicin Nanoparticles in Rat Tongue Cancer Induced by 4-Nitroquinoline 1-Oxide

PURPOSE

Oral cancer is one of the most significant cancers in the world, and squamous cell carcinoma makes up about 94% of oral malignancies. The aim of the present study was to compare the efficacy of doxorubicin plus methotrexate - loaded nanoparticles on tongue squamous cell carcinoma induced by 4NQO and compare it with the commercial doxorubicin and methotrexate delivered orally on seventy SD male rats.

METHODS

70 rats were divided into five groups. During the study, the animals were weighed by a digital scale once a week. Number of mortalities was recorded in the data collection forms. At the end of the treatment, biopsy samples were taken from rat tongues in order to evaluate the severity of dysplasia and the extent of cell proliferation. The results were analyzed using ANOVA, descriptive statistics and chi-square test.

RESULTS

No statistically significant difference was found in the mean weight of five groups (p>0.05). No significant relationship was found between groups and mortality rate (P = 0. 39). In addition, there was a significant relationship between groups and the degree of dysplasia (P <0.001). The statistical analysis showed a significant relationship between groups and the rate of cell proliferation (p <0.001).

CONCLUSION

The results of the present study showed that the use of doxorubicin plus methotrexate - loaded nanoparticles orally had more therapeutic effects than commercial doxorubicin plus methotrexate.

Antibody and lectin target podoplanin to inhibit oral squamous carcinoma cell migration and viability by distinct mechanisms

Podoplanin (PDPN) is a unique transmembrane receptor that promotes tumor cell motility. Indeed, PDPN may serve as a chemotherapeutic target for primary and metastatic cancer cells, particularly oral squamous cell carcinoma (OSCC) cells that cause most oral cancers. Here, we studied how a monoclonal antibody (NZ-1) and lectin (MASL) that target PDPN affect human OSCC cell motility and viability. Both reagents inhibited the migration of PDPN expressing OSCC cells at nanomolar concentrations before inhibiting cell viability at micromolar concentrations. In addition, both reagents induced mitochondrial membrane permeability transition to kill OSCC cells that express PDPN by caspase independent nonapoptotic necrosis. Furthermore, MASL displayed a surprisingly robust ability to target PDPN on OSCC cells within minutes of exposure, and significantly inhibited human OSCC dissemination in zebrafish embryos. Moreover, we report that human OSCC cells formed tumors that expressed PDPN in mice, and induced PDPN expression in infiltrating host murine cancer associated fibroblasts. Taken together, these data suggest that antibodies and lectins may be utilized to combat OSCC and other cancers that express PDPN.

Gelsolin regulates proliferation, apoptosis, migration and invasion in human oral carcinoma cells

Gelsolin (GSN) is one of the most abundant actin-binding proteins, and is involved in several pathological processes, including Alzheimer's disease, cardiac injury and cancer. The aim of the present study was to assess the effect of GSN on the growth and motility of oral squamous cell carcinoma Tca8113 cells. The overexpression vector pcDNA3.1-GSN was transfected into Tca8113 cells and the stable GSN overexpression cell line was identified based on G418 antibiotic selection. The effect of GSN overexpression on the proliferation, apoptosis, migration and invasion of Tca8113 cells was examined using a cell counting kit-8 assay, flow cytometry and Transwell assays. The results revealed that GSN overexpression significantly promoted the cell proliferation and apoptosis of Tca8113 cells. In addition, Transwell assays demonstrated that the migration and invasion abilities of Tca8113 cells were enhanced by GSN overexpression. Therefore, the upregulation of GSN promotes cell growth and motility, indicating that it may perform a vital function in the progression of human oral cancers.

Molecular genetic study of novel biomarkers for early diagnosis of oral squamous cell carcinoma

Objectives: Early detection and treatment of an oral squamous cell carcinoma (OSCC) is critical because of its rapid growth, frequent lymph-node metastasis, and poor prognosis. However, no clinically-valuable methods of early diagnosis exist, and genetic analysis of OSCCs has yielded no biomarkers. Study Design: We investigated the expression of genes associated with inflammation in OSCCs via a quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis of microarray data. Tumor and normal tissues from five patients with an OSCC were used for microarray analysis. Differentially-expressed genes, identified using permutation, local pooled error (LPE), t-tests, and significance analysis of microarrays (SAM), were selected as candidate genetic markers. Results: Two groups corresponding to tissue identity were evident, implying that their differentially-expressed genes represented biological differences between tissues. Fifteen genes were identified using the Student’s paired t-test (p<0.05) and the SAM, with a false discovery rate of less than 0.02. Based on gene expression, these 15 genes can be used to classify an OSCC. A genetic analysis of functional networks and ontologies, validated by using a qRT-PCR analysis of the tissue samples, identified four genes, ADAM15, CDC7, IL12RB2 and TNFRSF8, that demonstrated excellent concordance with the microarray data. Conclusions: Our study demonstrated that four genes (ADAM15, CDC7, IL12RB2 and TNFRSF8) had potential as novel biomarkers for the diagnosis and the treatment of an OSCC.

Key words:Biomarker, microarray, quantitative reverse transcription polymerase chain reaction, oral squamous cell carcinoma, gene expression profiling.

Vascular endothelial growth factor receptor isoforms: are they present in oral squamous cell carcinoma?

PURPOSE

Although the clinical importance of vascular endothelial growth factor (VEGF) overexpression in oral squamous cell carcinoma (OSCC) has been investigated, there are limited data about the overexpression of VEGF receptors (VEGF-Rs) and their clinical importance. VEGF-R isoforms have proven influence on proliferation rates, metastasis, and survival in different neoplasms. This study was conducted to investigate VEGF-R expression levels in OSCC samples and to identify any clinical relevance.

MATERIALS AND METHODS

A retrospective cohort study design (n = 50) was used. Clinical data were gathered from patient charts. Validated immunohistochemical methods were applied to determine VEGF-R isoform expression by tumor cells. Descriptive and inferential statistics with respect to the variable scale were computed. The significance level was set at a P value less than or equal to .05.

RESULTS

This study found overexpression of different VEGF-R isoforms in 88% of examined specimens. Statistically important associations were detected between overexpression of specific VEGF-Rs and tumor size, neck node metastasis, and tumor-associated death. Furthermore, a history of common OSCC risk factors (smoking and alcohol consumption) were found considerably more often in patients whose OSCC specimens displayed VEGF-R overexpression.

CONCLUSION

These findings show that VEGF-R overexpression occurs frequently in OSCC and could have clinical implications.

Agrin and perlecan mediate tumorigenic processes in oral squamous cell carcinoma

Oral squamous cell carcinoma is the most common type of cancer in the oral cavity, representing more than 90% of all oral cancers. The characterization of altered molecules in oral cancer is essential to understand molecular mechanisms underlying tumor progression as well as to contribute to cancer biomarker and therapeutic target discovery. Proteoglycans are key molecular effectors of cell surface and pericellular microenvironments, performing multiple functions in cancer. Two of the major basement membrane proteoglycans, agrin and perlecan, were investigated in this study regarding their role in oral cancer. Using real time quantitative PCR (qRT-PCR), we showed that agrin and perlecan are highly expressed in oral squamous cell carcinoma. Interestingly, cell lines originated from distinct sites showed different expression of agrin and perlecan. Enzymatically targeting chondroitin sulfate modification by chondroitinase, oral squamous carcinoma cell line had a reduced ability to adhere to extracellular matrix proteins and increased sensibility to cisplatin. Additionally, knockdown of agrin and perlecan promoted a decrease on cell migration and adhesion, and on resistance of cells to cisplatin. Our study showed, for the first time, a negative regulation on oral cancer-associated events by either targeting chondroitin sulfate content or agrin and perlecan levels.

Identification of host-immune response protein candidates in the sera of human oral squamous cell carcinoma patients

One of the most common cancers worldwide is oral squamous cell carcinoma (OSCC), which is associated with a significant death rate and has been linked to several risk factors. Notably, failure to detect these neoplasms at an early stage represents a fundamental barrier to improving the survival and quality of life of OSCC patients. In the present study, serum samples from OSCC patients (n = 25) and healthy controls (n = 25) were subjected to two-dimensional gel electrophoresis (2-DE) and silver staining in order to identify biomarkers that might allow early diagnosis. In this regard, 2-DE spots corresponding to various up- and down-regulated proteins were sequenced via high-resolution MALDI-TOF mass spectrometry and analyzed using the MASCOT database. We identified the following differentially expressed host-specific proteins within sera from OSCC patients: leucine-rich α2-glycoprotein (LRG), alpha-1-B-glycoprotein (ABG), clusterin (CLU), PRO2044, haptoglobin (HAP), complement C3c (C3), proapolipoprotein A1 (proapo-A1), and retinol-binding protein 4 precursor (RBP4). Moreover, five non-host factors were detected, including bacterial antigens from Acinetobacter lwoffii, Burkholderia multivorans, Myxococcus xanthus, Laribacter hongkongensis, and Streptococcus salivarius. Subsequently, we analyzed the immunogenicity of these proteins using pooled sera from OSCC patients. In this regard, five of these candidate biomarkers were found to be immunoreactive: CLU, HAP, C3, proapo-A1 and RBP4. Taken together, our immunoproteomics approach has identified various serum biomarkers that could facilitate the development of early diagnostic tools for OSCC.

Unraveling the molecular genetics of head and neck cancer through genome-wide approaches

The past decade has seen an unprecedented increase in our understanding of the biology and etiology of head and neck squamous cell carcinomas (HNSCC). Genome-wide sequencing projects have identified a number of recurrently mutated genes, including unexpected alterations in the NOTCH pathway and chromatin related genes. Gene-expression profiling has identified 4 distinct genetic subtypes which show some parallels to lung squamous cell carcinoma biology. The identification of the human papilloma virus as one causative agent in a subset of oropharyngeal cancers and their association with a favorable prognosis has opened up avenues for new therapeutic strategies. The expanding knowledge of the underlying molecular abnormalities in this once very poorly understood cancer should allow for increasingly rational clinical trial design and improved patient outcomes.

The hMLH1 -93G>A promoter polymorphism is associates with outcomes in oral squamous cell carcinoma patients

BACKGROUND

The aim of this study was to investigate the impact of hMLH1 polymorphisms on treatment outcomes in patients with oral squamous cell carcinoma (OSCC).

METHODS

Genotypings were performed by direct DNA sequencing in peripheral blood leukocytes from 185 male OSCC patients. Patients received primary surgery with or without adjuvant radiotherapy. Two hMLH1 tag single nucleotide polymorphisms (SNPs)-rs1800734 (-93G>A in the promoter) and rs1540354 (in the third intron)-were chosen from the HapMap project. Overall survival (OS) and disease-free survival (DFS) were compared between different genotypes.

RESULTS

The hMLH1 rs1800734 and rs1540354 polymorphisms were in weak linkage disequilibrium (r (2) = 0.456). OSCC patients with the rs1800734 AA genotype had a significantly poor prognosis in both OS and DFS. This SNP can also predict the outcomes of OSCC patients with postoperative adjuvant radiotherapy, especially in advanced stage; however, no significant differences in patient outcomes were found for the hMLH1 rs1540354 genotypes.

CONCLUSIONS

Our results demonstrate that the hMLH1 -93G>A SNP is found to be associated with patient outcomes in OSCC. This SNP can also predict their treatment outcome of radiotherapy.

QKI impairs self-renewal and tumorigenicity of oral cancer cells via repression of SOX2

Cancer stem cells (CSCs) may contribute to tumor initiation, distant metastasis and chemo-resistance. One of RNA-binding proteins, Quaking (QKI), was reported to be a tumor suppressor. Here we showed that reduced QKI levels were observed in many human oral cancer samples. Moreover further reduction of QKI expression in CSCs was detected compared with non-CSCs in oral cancer cell lines. Overexpressing QKI in oral cancer cells significantly reduced CSC sphere formation and stem cell-associated genes. In tumor implanting nude mice model, QKI significantly impeded tumor initiation rates, tumor sizes and lung metastasis rates. As a contrast, knocking down QKI enhanced the above effects. Among the putative CSC target genes, SOX2 expression was negatively affected by QKI, mechanism study revealed that QKI may directly regulate SOX2 expression via specific binding with its 3'UTR in a cis element-dependent way. Loss of SOX2 even completely reversed the sphere forming ability in QKI knockdown cell line. Taken together, these data demonstrated that SOX2 is an important CSC regulator in oral cancer. QKI is a novel CSC inhibitor and impaired multiple oral CSC properties via partial repression of SOX2. Therefore, reduced expression of QKI may provide a novel diagnostic marker for oral cancer.

Promoter region hypermethylation and mRNA expression of MGMT and p16 genes in tissue and blood samples of human premalignant oral lesions and oral squamous cell carcinoma

Promoter methylation and relative gene expression of O(6)-methyguanine-DNA-methyltransferase (MGMT) and p16 genes were examined in tissue and blood samples of patients with premalignant oral lesions (PMOLs) and oral squamous cell carcinoma (OSCC). Methylation-specific PCR and reverse transcriptase PCR were performed in 146 tissue and blood samples from controls and patients with PMOLs and OSCC. In PMOL group, significant promoter methylation of MGMT and p16 genes was observed in 59% (P = 0.0010) and 57% (P = 0.0016) of tissue samples, respectively, and 39% (P = 0.0135) and 33% (P = 0.0074) of blood samples, respectively. Promoter methylation of both genes was more frequent in patients with OSCC, that is, 76% (P = 0.0001) and 82% (P = 0.0001) in tissue and 57% (P = 0.0002) and 70% (P = 0.0001) in blood, respectively. Significant downregulation of MGMT and p16 mRNA expression was observed in both tissue and blood samples from patients with PMOLs and OSCC. Hypermethylation-induced transcriptional silencing of MGMT and p16 genes in both precancer and cancer suggests important role of these changes in progression of premalignant state to malignancy. Results support use of blood as potential surrogate to tissue samples for screening or diagnosing PMOLs and early OSCC.

Cyclin D1 overexpression is associated with poor clinicopathological outcome and survival in oral squamous cell carcinoma in Asian populations: insights from a meta-analysis

Background

The clinicopathological significance of cyclin D1 overexpression and prognosis of oral squamous cell carcinoma has not been fully quantified. We performed a comprehensive meta-analysis for evaluation of cyclin D1 overexpression in oral squamous cell carcinoma to determine the strength of this association.

Methods

Using both medical subheadings and free terms, we searched PubMed, Embase and the Institute for Scientific Information Web of Science for all eligible studies published before Nov. 2013. We retrieved 1674 citations, determining that 15 met the selection criteria. We used the odds ratio (OR) and hazard ratio (HR) as the common measures of association to quantitatively determine the correlation between cyclin D1 overexpression and outcomes of oral cancer. We performed a meta-analysis and heterogeneity, sensitivity, and subgroup analyses to clarify and validate the pooled results.

Results

The pooled results provided compelling evidence that cyclin D1 overexpression was significantly correlated with increased tumor size (OR = 1.617, 95% confidence interval [CI] = 1.046–2.498, p = 0.031), lymphoid node metastasis (OR = 2.035, 95% CI = 1.572–2.635, p<0.001), tumor differentiation (OR = 1.976, 95% CI = 1.363–2.866, p<0.001), and advancement of clinical stages (OR = 1.516, 95% CI = 1.140–2.015, p = 0.004), and adversely influenced overall survival of OSCC patients (HR = 1.897, 95% CI = 1.577–2.282, p<0.001). The strength of association varied in different oral cavity subsites.

Conclusion

Our findings indicated that cyclin D1 expression correlates with detrimental clinicopathological outcome and poor prognosis in oral squamous cell carcinoma. Our results may be useful in the management of oral cancer.

Nonparametric network design and analysis of disease genes in oral cancer progression

Biological networks in living organisms can be seen as the ultimate means of understanding the underlying mechanisms in complex diseases, such as oral cancer. During the last decade, many algorithms based on high-throughput genomic data have been developed to unravel the complexity of gene network construction and their progression in time. However, the small size of samples compared to the number of observed genes makes the inference of the network structure quite challenging. In this study, we propose a framework for constructing and analyzing gene networks from sparse experimental temporal data and investigate its potential in oral cancer. We use two network models based on partial correlations and kernel density estimation, in order to capture the genetic interactions. Using this network construction framework on real clinical data of the tissue and blood at different time stages, we identified common disease-related structures that may decipher the association between disease state and biological processes in oral cancer. Our study emphasizes an altered MET (hepatocyte growth factor receptor) network during oral cancer progression. In addition, we demonstrate that the functional changes of gene interactions during oral cancer progression might be particularly useful for patient categorization at the time of diagnosis and/or at follow-up periods.

Expression of matriptase correlates with tumour progression and clinical prognosis in oral squamous cell carcinoma

AIMS

To investigate the relationship of matriptase expression in oral squamous cell carcinoma (OSCC) to clinicopathological characteristics, patient survival and cell-invasive properties.

METHODS AND RESULTS

Matriptase expression in OSCC was evaluated by immunohistochemical staining, and its relationship to clinicopathological features and outcomes was assessed statistically. The shRNA-mediated stable knockdown of matriptase in OSCC cells was used to analyse cell proliferation, migration and invasion in vitro. Matriptase immunostaining score was correlated with histopathological grade, clinical stage, positive lymph node and distant metastasis, and higher matriptase immunostaining score was associated significantly with poor prognosis. Elevated matriptase expression in oral cancer cell lines was a significant promoter of oral cancer cell migration and invasion.

CONCLUSIONS

Matriptase expression correlates with tumour progression and invasive capability in OSCC and may be an adverse prognostic marker for this cancer.

ADAM17 mediates OSCC development in an orthotopic murine model

BACKGROUND

ADAM17 is one of the main sheddases of the cells and it is responsible for the cleavage and the release of ectodomains of important signaling molecules, such as EGFR ligands. Despite the known crosstalk between ADAM17 and EGFR, which has been considered a promising targeted therapy in oral squamous cell carcinoma (OSCC), the role of ADAM17 in OSCC development is not clear.

METHOD

In this study the effect of overexpressing ADAM17 in cell migration, viability, adhesion and proliferation was comprehensively appraised in vitro. In addition, the tumor size, tumor proliferative activity, tumor collagenase activity and MS-based proteomics of tumor tissues have been evaluated by injecting tumorigenic squamous carcinoma cells (SCC-9) overexpressing ADAM17 in immunodeficient mice.

RESULTS

The proteomic analysis has effectively identified a total of 2,194 proteins in control and tumor tissues. Among these, 110 proteins have been down-regulated and 90 have been up-regulated in tumor tissues. Biological network analysis has uncovered that overexpression of ADAM17 regulates Erk pathway in OSCC and further indicates proteins regulated by the overexpression of ADAM17 in the respective pathway. These results are also supported by the evidences of higher viability, migration, adhesion and proliferation in SCC-9 or A431 cells in vitro along with the increase of tumor size and proliferative activity and higher tissue collagenase activity as an outcome of ADAM17 overexpression.

CONCLUSION

These findings contribute to understand the role of ADAM17 in oral cancer development and as a potential therapeutic target in oral cancer. In addition, our study also provides the basis for the development of novel and refined OSCC-targeting approaches.

COX-2, MMP-7 expression in oral lichen planus and oral squamous cell carcinoma

OBJECTIVE

To observe cyclooxygenase (COX)-2 expression in normal oral mucosa (NOM), oral lichen planus (OLP) and oral squamous cell carcinoma (OSCC) and explore its significance in the incidence of oral cancer.

METHODS

The immunohistochemical method and RT-PCR method were applied to detect the expression of COX-2 and MMP-7 in 10 cases with NOM, 33 cases of with OLP and 38 cases with OSCC.

RESULTS

The expression of COX-2 mRNA in OSCC tissues (68.4%, 26/38) was significantly higher than in the OLP (24.2%, 8/33) and NOM (0.0%, 0/10) (P<0.01). The expression of MMP-7 mRNA in OSCC tissues (65.8%, 25/38) was significantly higher than in the OLP (30.3%, 10/33) and NOM (0.0%, 0/10) (P<0.01). The expression of MMP-7 in OLP was significantly higher than in the NOM (P<0.05). There was no significant expression of COX-2 protein in NOM, and the positive rate was 42.4% (14/33) and 89.5% (34/38) in OLP and OSCC group, respectively. The COX-2 expression in cancer tissues was significantly higher than in NOM and OLP (P<0.05). The MMP-7 protein expression in cancer tissues (84.2%, 32/38) was significantly higher than in NOM (10.0%, 1/10) and in OLP (42.4%, 14/33), and the positive rate in OLP was significantly higher than in NOM (P< 0.01). The COX-2 expression was associated with clinical stage (P<0.05), the MMP-7 expression was associated with clinical stage and lymph node metastasis (P<0.05). The expressions of COX-2 and MMP-7 mRNA were positively correlated with OSCC.

CONCLUSIONS

The abnormal expressions of COX-2 and MMP-7 are closely related to the biological behavior of OSCC, the MMP-7 may be induced by COX-2, and further lead to the invasion and metastasis of OSCC.

Additional cytosine inside mitochondrial C-tract D-loop as a progression risk factor in oral precancer cases

INTRODUCTION

Alterations inside Polycytosine tract (C-tract) of mitochondrial DNA (mtDNA) have been described in many different tumor types. The Poly-Cytosine region is located within the mtDNA D-loop region which acts as point of mitochondrial replication origin. A suggested pathogenesis is that it interferes with the replication process of mtDNA which in turn affects the mitochondrial functioning and generates disease.

METHODOLOGY

100 premalignant cases (50 leukoplakia & 50 oral submucous fibrosis) were selected and the mitochondrial DNA were isolated from the lesion tissues and from the blood samples. Polycytosine tract in mtDNA was sequenced by direct capillary sequencing.

RESULTS

40 (25 leukoplakia & 15 oral submucous fibrosis) patients harbored lesions that displayed one additional cytosine after nucleotide thymidine (7CT6C) at nt position 316 in C-tract of mtDNA which were absent in corresponding mtDNA derived from blood samples.

CONCLUSION

Our results show an additional cytosine in the mtDNA at polycytosine site in oral precancer cases. It is postulated that any increase/decrease in the number of cytosine residues in the Poly-Cytosine region may affect the rate of mtDNA replication by impairing the binding of polymerase and other transacting factors. By promoting mitochondrial genomic instability, it may have a central role in the dysregulation of mtDNA functioning, for example alterations in energy metabolism that may promote tumor development. We, therefore, report and propose that this alteration may represent the early development of oral cancer. Further studies with large number of samples are needed in to confirm the role of such mutation in carcinogenesis.

The fatty acid synthase inhibitor orlistat reduces the growth and metastasis of orthotopic tongue oral squamous cell carcinomas

Fatty acid synthase (FASN) is the biosynthetic enzyme responsible for the endogenous synthesis of fatty acids. It is downregulated in most normal cells, except in lipogenic tissues such as liver, lactating breast, fetal lung, and adipose tissue. Conversely, several human cancers, including head and neck squamous cell carcinomas (HNSCC), overexpress FASN, which has been associated with poor prognosis and recently suggested as a metabolic oncoprotein. Orlistat is an irreversible inhibitor of FASN activity with cytotoxic properties on several cancer cell lines that inhibits tumor progression and metastasis in prostate cancer xenografts and experimental melanomas, respectively. To explore whether the inhibition of FASN could impact oral tongue squamous cell carcinoma (OTSCC) metastatic spread, an orthotopic model was developed by the implantation of SCC-9 ZsGreen LN-1 cells into the tongue of BALB/c nude mice. These cells were isolated through in vivo selection, show a more invasive behavior in vitro than the parental cells, and generate orthotopic tumors that spontaneously metastasize to cervical lymph nodes in 10 to 15 days only. SCC-9 ZsGreen LN-1 cells also exhibit enhanced production of MMP-2, ERBB2, and CDH2. The treatment with orlistat reduced proliferation and migration, promoted apoptosis, and stimulated the secretion of VEGFA165b by SCC-9 ZsGreen LN-1 cells. In vivo, the drug was able to decrease both the volume and proliferation indexes of the tongue orthotopic tumors and, importantly, reduced the number of metastatic cervical lymph nodes by 43%. These results suggest that FASN is a potential molecular target for the chemotherapy of patients with OTSCC.

Cytokines and tumor metastasis gene variants in oral cancer and precancer in Puerto Rico

Objectives

A cross-sectional epidemiological study explored genetic susceptibility to oral precancer and cancer in Puerto Rico (PR).

Materials and Methods

Three hundred three individuals with a benign oral condition, oral precancer (oral epithelial hyperplasia/hyperkeratosis, oral epithelial dysplasia), or oral squamous cell carcinoma (SCCA) were identified via PR pathology laboratories. A standardized, structured questionnaire obtained information on epidemiological variables; buccal cells were collected for genetic analysis. Genotyping was performed using Taqman® assays. Allelic frequencies of single nucleotide polymorphisms (SNPs) were evaluated in cytokine genes and genes influencing tumor metastasis. Risk estimates for a diagnosis of oral precancer or SCCA while having a variant allele were generated using logistic regression. Adjusted models controlled for age, gender, ancestry, education, smoking and alcohol consumption.

Results

Relative to persons with a benign oral lesion, individuals with homozygous recessive allelic variants of tumor necrosis factor (TNF-α) −238 A/G SNP had a reduced odds of having an oral precancer (OR_adjusted = 0.15; 95% CI 0.03–0.70). The transforming growth factor beta-1 (TGFβ-1 −509 C/T) polymorphism was inversely associated with having an oral SCCA among persons homozygous for the recessive variant (OR_crude = 0.27; 95% CI 0.09–0.79). The matrix metalloproteinase gene (MMP-1) variant, rs5854, was associated with oral SCCA; participants with even one variant allele were more likely to have oral SCCA (OR_adjusted = 2.62, 95% CI 1.05–6.53) compared to people with ancestral alleles.

Conclusion

Our exploratory analyses suggest that genetic alterations in immune system genes and genes with metastatic potential are associated with oral precancer and SCCA risk in PR.

Oral squamous cell carcinoma and serum paraoxonase 1

BACKGROUND

Serum paraoxonase 1 is involved in mechanisms that protect cells from oxidative stress damage. This study aimed to investigate the correlation between serum paraoxonase 1 activity and polymorphisms in patients with oral squamous cell carcinoma.

METHODS AND MATERIALS

Fifty-seven patients with oral squamous cell carcinoma and 59 matched healthy controls participated in the study. Serum paraoxonase 1 activity and polymorphisms in blood samples were compared with results for polymerase chain reaction and restriction fragment length polymorphism tests.

RESULTS

Mean serum paraoxonase 1 activity levels were lower in patients than controls (mean ± standard deviation, 21.9 ± 5 units/l and 120.4 ± 2 units/l, respectively) (p = 0.001). The serum paraoxonase 1 192 glutamine polymorphism was more common in patients than controls.

CONCLUSION

Patients with oral squamous cell carcinoma had significantly lower serum paraoxonase 1 activity levels and a greater prevalence of the serum paraoxonase 1 192 glutamine allele, compared with controls. Serum paraoxonase 1 may play a role in the aetiology of oral squamous cell carcinoma.

A survey of barriers to screening for oral cancer among rural Black Americans

OBJECTIVE

Research documents a disparity between Black and White Americans in mortality for oral cancer that appears to result in part from behaviors such as lower oral cancer screening among Black Americans. We examined barriers to oral cancer screening among Black Americans.

METHODS

We surveyed Black Americans (N = 366) living in rural Florida to identify barriers to getting screened for oral cancer.

RESULTS

Low knowledge/social attention, lack of resources, and fear/defensive avoidance predicted screening intentions, with lack of resources emerging as the largest barrier. Participants also reported that a recommendation from their provider was most likely to increase screening intentions, whereas encountering financial barriers was most likely to decrease screening intentions.

CONCLUSIONS

Low knowledge/social attention, lack of resources, and fear/defensive avoidance emerged as independent barriers to oral cancer screening, with the latter two barriers accounting for the most variance in intentions to get screened.

Head and neck cancer: causes, prevention and treatment

Abstract

Although head and neck carcinoma ranks fifth among cancer types, patient survival rates have not changed significantly over the past years.

Objective

To determine the risk factors, causes, therapies, and prevention measures for head and neck cancer.

Method

Risk factors, causes, therapies, and preventive measures for this disease were searched on databases PUBMED, MEDLINE, and SciELO.

Results

Alcohol and tobacco are still atop risk factors. Other factors may influence the development of head and neck carcinoma. Surgery is the main treatment option, and the addition of radiotherapy following surgery is frequent for patients in the early stages of the disease. Other therapies target specific genetic molecular components connected to tumor development. Disease preventive measures include smoking cessation, limiting alcohol intake, preventing exposure to tobacco smoke and environmental carcinogenic agents, early detection of infection by HPV, maintaining oral health, good eating habits, and managing stress.

Conclusion

Additional research is needed for a more thorough understanding of the development of head and neck carcinomas and to shed light on new ways to improve therapeutic approaches and interventions.

Porphyromonas gingivalis promotes invasion of oral squamous cell carcinoma through induction of proMMP9 and its activation

Recent epidemiological studies have revealed a significant association between periodontitis and oral squamous cell carcinoma (OSCC). Furthermore, matrix metalloproteinase 9 (MMP9) is implicated in the invasion and metastasis of tumour cells. We examined the involvement of Porphyromonas gingivalis, a periodontal pathogen, in OSCC invasion through induced expression of proMMP and its activation. proMMP9 was continuously secreted from carcinoma SAS cells, while P. gingivalis infection increased proenzyme expression and subsequently processed it to active MMP9 in culture supernatant, which enhanced cellular invasion. In contrast, Fusobacterium nucleatum, another periodontal organism, failed to demonstrate such activities. The effects of P. gingivalis were observed with highly invasive cells, but not with the low invasivetype. P. gingivalis also stimulated proteinase-activated receptor 2 (PAR2) and enhanced proMMP9 expression, which promoted cellular invasion. P. gingivalis mutants deficient in gingipain proteases failed to activate MMP9. Infected SAS cells exhibited activation of ERK1/2, p38, and NF-kB, and their inhibitors diminished both proMMP9-overexpression and cellular invasion. Together, our results show that P. gingivalis activates the ERK1/2-Ets1, p38/HSP27, and PAR2/NF-kB pathways to induce proMMP9 expression, after which the proenzyme is activated by gingipains to promote cellular invasion of OSCC cell lines. These findings suggest a novel mechanism of progression and metastasis of OSCC associated with periodontitis.

Depth of invasion, tumor budding, and worst pattern of invasion: prognostic indicators in early-stage oral tongue cancer

Background

Oral (mobile) tongue squamous cell carcinoma (SCC) is characterized by a highly variable prognosis in early-stage disease (T1/T2 N0M0). The ability to classify early oral tongue SCCs into low-risk and high-risk categories would represent a major advancement in their management.

Methods

Depth of invasion, tumor budding, histologic risk-assessment score (HRS), and cancer-associated fibroblast (CAF) density were studied in 233 cases of T1/T2 N0M0 oral tongue SCC managed in 5 university hospitals in Finland.

Results

Tumor budding (≥5 clusters at the invasive front of the tumor) and depth of invasion (≥4 mm) were associated with poor prognosis in patients with early oral tongue SCC (hazard ratio [HR], 2.04; 95% confidence interval [CI], 1.17–3.55; HR, 2.55; 95% CI, 1.25–5.20, respectively) after multivariate analysis. The HRS and CAF density did not predict survival. However, high-risk worst pattern of invasion (WPOI), a component of HRS, was also an independent prognostic factor (HR, 4.47; 95% CI, 1.59–12.51).

Conclusion

Analyzing the depth of invasion, tumor budding, and/or WPOI in prognostication and treatment planning of T1/T2 N0M0 oral tongue SCC is recommended.

Co-expression of CD44+/RANKL+ tumor cells in the carcinogenesis of oral squamous cell carcinoma

Receptor activator of nuclear factor-kappa (RANK)/receptor activator of nuclear factor-kappa B ligand (RANKL) signaling helps putative cancer stem cells (CSC) to maintain their stemness. Expression of CD44 and RANKL was analyzed in oral squamous cell carcinoma specimen (n = 191). Moreover, RANKL expression was measured in cancer cell lines (BICR3, BICR56) by immunohistochemistry and western blot analysis. Scanned images were digitally analyzed using ImageJ and the immunomembrane plug-in. CD44 and RANKL expression on protein level was correlated with clinical characteristics and impact on survival. RANKL was co-labeled with CD44 in immunohistochemical and immunofluorescence double labeling experiments. Although high CD44+/RANKL+ co-expression was significantly associated with clinicopathological factors and worse survival, multivariate analysis did not demonstrate high CD44+/RANKL+ co-expression as independent prognostic factor. Immunohistochemical and immunofluorescence double labeling experiments revealed RANKL expression by CD44+ cancer cells. RANKL specificity was confirmed by western blot analysis. For the first time, this study provides evidence that RANKL expression in OSCC might be associated with disease recurrence and a cell compartment measured by CD44+/RANKL+ co-expression within the mucosal epithelial basal layer cells.

Chromosomal instability, aneuploidy and routine high-resolution DNA content analysis in oral cancer risk evaluation

Carcinogen exposure of the oral cavity is thought to create an extensive 'field cancerization'. According to this model, a very early precursor of oral cancer is a patch of normal-appearing mucosa in which stem cells share genetic/genomic aberrations. These precancerous fields then become clinically visible as white and red lesions (leuko- and erythro-plakias), which represent the vast majority of the oral potentially malignant disorders. This review focuses on aneuploidy (where it is from) and on biomarkers associated with DNA aneuploidy in oral mucosa and oral potentially malignant disorders, as detected by DNA image and flow cytometry. Data from the literature strongly support the association of DNA ploidy with dysplasia. However, work is still needed to prove the clinical value of DNA ploidy in large-scale prospective studies. Using high-resolution DNA flow cytometry with fresh/frozen material and the degree of DNA aneuploidy (DNA Index) might improve the prediction of risk of oral cancer development.

Chromosomal instability, DNA index, dysplasia, and subsite in oral premalignancy as intermediate endpoints of risk of cancer

BACKGROUND

Chromosomal instability and aneuploidy may represent biomarkers of oral exposure to damaging agents and early signs of clinical disease according to the theory of "oral field cancerization."

METHODS

The hypothesis was tested that the DNA index (DI) values, obtained by high-resolution DNA flow cytometry (DNA-FCM), may potentially contribute to oral cancer risk prediction. For this purpose, the DI of oral fields of normal-appearing mucosa and oral potentially malignant disorders (OPMDs) in 165 consecutive patients was tested for association with dysplasia and/or the oral subsites of tongue and floor of the mouth taken as high-risk intermediate endpoints surrogate of cancer clinical endpoints. The association was evaluated by logistic regression using patient gender, age, tobacco, cigarette smoking habit, and alcohol abuse as confounding variables.

RESULTS

Different DI models provided evidence of statistical significant associations. Subdividing the DI values in diploid, near-diploid aneuploid, and high or multiple aneuploid from both OPMDs and oral normal-appearing mucosa, ORs, respectively, of 1, 4.3 (P = 0.001), and 18.4 (P < 0.0005) were obtained.

CONCLUSION

Routine DI analysis by high-resolution DNA-FCM seems potentially useful to complement dysplasia and subsite analysis for assessment of oral cancer risk prediction and for a better management of the patients with OPMDs. Work is in progress to validate the present findings in a prospective study with clinical endpoints.

IMPACT

Identifying DNA abnormalities in oral premalignancy may lead to biomarkers of oral exposure and cancer risk and potentially to more effective prevention measures.

Honokiol Eliminates Human Oral Cancer Stem-Like Cells Accompanied with Suppression of Wnt/ β -Catenin Signaling and Apoptosis Induction

Honokiol, an active compound of Magnolia officinalis, exerted many anticancer effects on various types of cancer cells. We explored its effects on the elimination of cancer stem-like side population (SP) cells in human oral squamous cell carcinoma SAS cells. The sorted SP cells possessed much higher expression of stemness genes, such as ABCG2, ABCC5, EpCAM, OCT-4, CD133, CD44, and β-catenin, and more clonogenicity as compared with the Non-SP cells. After 48 h of treatment, honokiol dose dependently reduced the proportion of SP from 2.53% to 0.09%. Apoptosis of honokiol-treated SP cells was evidenced by increased annexin V staining and cleaved caspase-3 as well as decreased Survivin and Bcl-2. Mechanistically, honokiol inhibited the CD44 and Wnt/β-catenin signaling of SP cells. The Wnt signaling transducers such as β-catenin and TCF-4 were decreased in honokiol-treated SP cells, while the β-catenin degradation promoting kinase GSK-3α/β was increased. Consistently, the protein levels of β-catenin downstream targets such as c-Myc and Cyclin D1 were also downregulated. Furthermore, the β-catenin-related EMT markers such as Slug and Snail were markedly suppressed by honokiol. Our findings indicate honokiol may be able to eliminate oral cancer stem cells through apoptosis induction, suppression of Wnt/β-catenin signaling, and inhibition of EMT.

Survival of patients with oral cavity cancer in Germany

The purpose of the present study was to describe the survival of patients diagnosed with oral cavity cancer in Germany. The analyses relied on data from eleven population-based cancer registries in Germany covering a population of 33 million inhabitants. Patients with a diagnosis of oral cavity cancer (ICD-10: C00-06) between 1997 and 2006 are included. Period analysis for 2002-2006 was applied to estimate five-year age-standardized relative survival, taking into account patients' sex as well as grade and tumor stage. Overall five-year relative survival for oral cavity cancer patients was 54.6%. According to tumor localization, five-year survival was 86.5% for lip cancer, 48.1% for tongue cancer and 51.7% for other regions of the oral cavity. Differences in survival were identified with respect to age, sex, tumor grade and stage. The present study is the first to provide a comprehensive overview on survival of oral cavity cancer patients in Germany.

How should we manage oral leukoplakia?

The aim of this article is to review the management of oral leukoplakia. The topics of interest are clinical diagnosis, methods of management and their outcome, factors associated with malignant transformation, prognosis, and clinical follow-up. Global prevalence is estimated to range from 0.5 to 3.4%. The point prevalence is estimated to be 2.6% (95% CI 1.72-2.74) with a reported rate of malignant transformation ranging from 0.13 to 17.5%. Incisional biopsy with scalpel and histopathological examination of the suspicious tissue is still the gold standard for diagnosis. A number of factors such as age, type of lesion, site and size, dysplasia, and DNA content have been associated with increased risk of malignant transformation, but no single reliable biomarker has been shown to be predictive. Various non-surgical and surgical treatments have been reported, but currently there is no consensus on the most appropriate one. Randomised controlled trials for non-surgical treatment show no evidence of effective prevention of malignant transformation and recurrence. Conventional surgery has its own limitations with respect to the size and site of the lesion but laser surgery has shown some encouraging results. There is no universal consensus on the duration or interval of follow-up of patients with the condition.

Genetic variations in key microRNA processing genes and risk of head and neck cancer: a case-control study in Chinese population

MicroRNAs (miRNAs) have been reported to play a key role in oncogenesis. Genetic variations in miRNA processing genes and miRNA binding sites may affect the biogenesis of miRNA and the miRNA-mRNA interactions, hence promoting tumorigenesis. In the present study, we hypothesized that potentially functional polymorphisms in miRNA processing genes may contribute to head and neck cancer (HNC) susceptibility. To test this hypothesis, we genotyped three SNPs at miRNA binding sites of miRNA processing genes (rs1057035 in 3'UTR of DICER, rs3803012 in 3'UTR of RAN and rs10773771 in 3'UTR of HIWI) with a case-control study including 397 HNC cases and 900 controls matched by age and sex in Chinese. Although none of three SNPs was significantly associated with overall risk of HNC, rs1057035 in 3'UTR of DICER was associated with a significantly decreased risk of oral cancer (TC/CC vs. TT: adjusted OR  =  0.65, 95% CI  =  0.46-0.92). Furthermore, luciferase activity assay showed that rs1057035 variant C allele led to significantly lower expression levels as compared to the T allele, which may be due to the relatively high inhibition of hsa-miR-574-3p on DICER mRNA. These findings indicated that rs1057035 located at 3'UTR of DICER may contribute to the risk of oral cancer by affecting the binding of miRNAs to DICER. Large-scale and well-designed studies are warranted to validate our findings.

Racial disparity in oral and pharyngeal cancer in Florida in 1991-2008: mixed trends in stage of diagnosis

OBJECTIVES

To explore changes in distribution of stage at diagnosis among individuals with oral and pharyngeal cancers over the past two decades and whether the changes differ by race.

METHODS

We obtained 1991-2008 cancer incidence data for nine anatomic sites of the oral and pharyngeal structure from the Florida Cancer Data System. These cancers were grouped into oral squamous cell carcinoma (SCC), pharyngeal SCC, and other head and neck cancers. Annual percent change was calculated for each group to characterize trends in age-adjusted cancer incidence over time by race and stage at diagnosis.

RESULTS

During 1991-2008, the overall age-adjusted oral SCC incidence was decreasing for both races, with a greater decline observed among Blacks. There was a large drop in incidence of regional-stage diagnoses among Blacks. For pharyngeal SCC, the age-adjusted incidence of localized- and regional-stage diagnoses was increasing for Whites during 1991-2008, with the largest increase in the incidence of regional-stage diagnoses. The percentage of localized-stage diagnoses was increasing for both races for oral SCC. A slight increase in percentage of localized-stage diagnoses was observed for Blacks for pharyngeal SCC, whereas no obvious change was observed among Whites.

CONCLUSIONS

Blacks continued to have lower percentages of localized-stage diagnoses than Whites for nearly all sites, but an increasing percentage of localized-stage diagnoses was observed for oral SCC among Blacks. For pharyngeal SCC, the increase in incidence among Whites was accompanied by an increasing percentage of late-stage diagnoses. Coordinated public health approaches with a special emphasis on screening underserved populations are needed.