Overexpression of matrix metalloproteinase-1 and -9 mRNA is associated with progression of oral dysplasia to cancer

Causal associations of MICB, CTSA, and MMP9 proteins with oral cancer: Mendelian randomization study

Oral cancer (ORCA) is the most prevalent histological subtype of oral malignancies in which immune modulation is relevant. The goal of this work was to employ Mendelian randomization (MR) to investigate the causal connection between the immune-related proteins MICB, CTSA, MMP9, and ORCA. The Open GWAS database of the Integrative Epidemiology Unit (IEU) was accessed to collect GWAS data for ORCA (ieu-b-4961), MICB (prot-a-1898), CTSA (prot-a-717) and MMP9 (prot-a-1921). From 372,373 samples, the ORCA dataset comprises 7,723,107 single nucleotide polymorphisms (SNPs). MICB, CTSA, and MMP9 all have 10,534,735 SNPs and 3,301 sample sizes. Then, the primary SVMR implementation approaches were weighted mode, simple mode, inverse variance weighted (IVW), weighted median, and MR-Egger. IVW was the most effective technique. A sensitivity study was also carried out to assess the correctness of SVMR data, with special focus devoted to heterogeneity, horizontal pleiotropy, and Leave-One-Out (LOO). MVMR was eventually implemented as well. A Mendelian randomization analysis of the three exposure factors in the dataset (ieu-b-94, ebi-a-GCST012237) was also performed to validate the study results. According to the SVMR results, there was a noteworthy causal interaction between ORCA and MICB (P = 0.0014), MMP9 (P = 0.0343), and CTSA (P = 0.0003). Furthermore, odds ratios (ORs) values revealed that MMP9 (OR = 1.0005) was an ORCA risk factor, whereas MICB (OR = 0.9994) and CTSA (OR = 0.9993) were security factors. The robustness of the SVMR findings was confirmed by the p-values of the heterogeneity and horizontal pleiotropy, both of which were greater than 0.05. The MVMR result did not affect any of the safety or hazard features of these three exposure factors. However, the P value for MMP9 was greater than 0.05, implying that MICB and CTSA may have a greater influence on ORCA than MMP9. The validation outcomes in both datasets harmonized with the findings from previous research, thereby solidifying the reliability of results. Our investigation provided a crucial resource for further research on the subject by demonstrating a causal relationship between ORCA and MICB, CTSA, and MMP9.

Prognostic biomarkers for malignant progression of oral epithelial dysplasia: an updated systematic review and meta-analysis

Oral epithelial dysplasia (OED) is a premalignant condition that carries an appreciable risk of malignant progression. The current grading system for severity, as defined by the World Health Organization, is a valuable clinical tool, but further work is required to improve the accuracy of predicting OED malignant progression. This systematic review aimed to assess progress in prognostic biomarker discovery in OED over the past 16 years. The primary objective was to update the latest evidence on prognostic biomarkers that may predict malignant progression of OED, with strict inclusion criteria of studies with a longitudinal design and long-term follow-up data to enhance the robustness and translational clinical potential of the findings. Of 2829 studies identified through the searching of five databases, 20 met our inclusion criteria. These studies investigated a total of 32 biomarkers, 20 of which demonstrated significant potential to predict malignant progression of OED. Meta-analysis demonstrated the significant prognostic value of four biomarkers: podoplanin, EGFR expression, p16 methylation, and DNA aneuploidy. Our review has identified 20 reported biomarkers with prognostic potential to predict malignant progression in OED, but their translation into clinical practice remains elusive. Further research is required, and this should focus on validating the promising biomarkers identified in large cohort studies, with adherence to standardised reporting guidelines.

Matrix Metalloproteinases and Their Inhibitors as Potential Prognostic Biomarkers in Head and Neck Cancer after Radiotherapy

Head and neck cancer (HNC) is among the ten most frequent tumours, with 5-year survival rates varying from 30% to 70% depending on the stage and location of the tumour. HNC is traditionally known as head and neck squamous cell carcinoma (HNSCC), since 90% arises from epithelial cells. Metastasis remains a major cause of mortality in patients with HNSCC. HNSCC patients with metastatic disease have an extremely poor prognosis with a survival rate of less than a year. Matrix metalloproteinases (MMPs) have been described as biomarkers that promote cell migration and invasion. Radiotherapy is widely used to treat HNSCC, being a determining factor in the alteration of the tumour's biology and microenvironment. This review focuses on analysing the current state of the scientific literature on this topic. Although few studies have focused on the role of these proteinases in HNC, some authors have concluded that radiotherapy alters the behaviour of MMPs and tissue inhibitors of metalloproteinases (TIMPs). Therefore, more research is needed to understand the roles played by MMPs and their inhibitors (TIMPs) as prognostic biomarkers in patients with HNC and their involvement in the response to radiotherapy.

Immunolocalization of epithelial cell adhesion molecule and matrix metalloproteinase-9 in oral epithelial dysplasia and oral squamous cell carcinoma

INTRODUCTION

Cancers are complex tissues composed of multiple distinct cell types that participate in heterotypic interactions with one another. Physiologically cell-to-cell contacts formed by dense populations of normal cells operate to suppress further cell proliferation.

OBJECTIVES

The objective of the study is to evaluate and compare the immunoexpression of matrix metalloproteinase-9 (MMP-9) and epithelial cell adhesion molecule (EpCAM) in oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC) and to hypothesize their role in the progression in varying grades of these lesions.

MATERIALS AND METHODS

A total of 60 samples comprising of 30 cases each of OED and OSCC. Three micrometers thin sections were taken and subjected for hematoxylin and eosin stain and immunohistochemical procedure. The sections were incubated with monoclonal anti-EpCAM anti-MMP-9 antibody. The data were analyzed using SPSS software version 19.

RESULTS

The results of the study show EpCAM immunoexpression decreased in OSCC when compared to OED. MMP-9 immunoexpression increased in OSCC when compared to OED (statistically significant, P ≤ 0.05).

CONCLUSION

Correlation between EpCAM and MMP-9 may help to unravel the signaling cascades involved in the carcinomatous changes, tumor cell invasion, and progression of OSCCs.

The Ca2+ channel ORAI1 is a regulator of oral cancer growth and nociceptive pain

Oral cancer causes pain associated with cancer progression. We report here that the function of the Ca2+ channel ORAI1 is an important regulator of oral cancer pain. ORAI1 was highly expressed in tumor samples from patients with oral cancer, and ORAI1 activation caused sustained Ca2+ influx in human oral cancer cells. RNA-seq analysis showed that ORAI1 regulated many genes encoding oral cancer markers such as metalloproteases (MMPs) and pain modulators. Compared with control cells, oral cancer cells lacking ORAI1 formed smaller tumors that elicited decreased allodynia when inoculated into mouse paws. Exposure of trigeminal ganglia neurons to MMP1 evoked an increase in action potentials. These data demonstrate an important role of ORAI1 in oral cancer progression and pain, potentially by controlling MMP1 abundance.

Systematic Review of Roles of Arecoline and Arecoline N-Oxide in Oral Cancer and Strategies to Block Carcinogenesis

Betel quid and areca nut are complex mixture carcinogens, but little is known about whether their derived single-agent arecoline or arecoline N-oxide (ANO) is carcinogenic, and the underlying mechanisms remain unclear. In this systematic review, we analyzed recent studies on the roles of arecoline and ANO in cancer and strategies to block carcinogenesis. In the oral cavity, flavin-containing monooxygenase 3 oxidizes arecoline to ANO, and both alkaloids conjugate with N-acetylcysteine to form mercapturic acid compounds, which are excreted in urine, reducing arecoline and ANO toxicity. However, detoxification may not be complete. Arecoline and ANO upregulated protein expression in oral cancer tissue from areca nut users compared to expression levels in adjacent normal tissue, suggesting a causal relationship between these compounds and oral cancer. Sublingual fibrosis, hyperplasia, and oral leukoplakia were diagnosed in mice subjected to oral mucosal smearing of ANO. ANO is more cytotoxic and genotoxic than arecoline. During carcinogenesis and metastasis, these compounds increase the expression of epithelial-mesenchymal transition (EMT) inducers such as reactive oxygen species, transforming growth factor-β1, Notch receptor-1, and inflammatory cytokines, and they activate EMT-related proteins. Arecoline-induced epigenetic markers such as sirtuin-1 hypermethylation, low protein expression of miR-22, and miR-886-3-p accelerate oral cancer progression. Antioxidants and targeted inhibitors of the EMT inducers used reduce the risk of oral cancer development and progression. Our review findings substantiate the association of arecoline and ANO with oral cancer. Both of these single compounds are likely carcinogenic to humans, and their mechanisms and pathways of carcinogenesis are useful indicators for cancer therapy and prognosis.

Developments on the Smart Hydrogel-Based Drug Delivery System for Oral Tumor Therapy

At present, an oral tumor is usually treated by surgery combined with preoperative or postoperative radiotherapies and chemotherapies. However, traditional chemotherapies frequently result in substantial toxic side effects, including bone marrow suppression, malfunction of the liver and kidneys, and neurotoxicity. As a new local drug delivery system, the smart drug delivery system based on hydrogel can control drug release in time and space, and effectively alleviate or avoid these problems. Environmentally responsive hydrogels for smart drug delivery could be triggered by temperature, photoelectricity, enzyme, and pH. An overview of the most recent research on smart hydrogels and their controlled-release drug delivery systems for the treatment of oral cancer is given in this review. It is anticipated that the local drug release method and environment-responsive benefits of smart hydrogels will offer a novel technique for the low-toxicity and highly effective treatment of oral malignancy.

Molecular Biomarkers of Malignant Transformation in Head and Neck Dysplasia

Head and neck squamous cell carcinoma (HNSCC) and its treatments are associated with substantial morbidity, often resulting in cosmetic deformity and loss of physiologic functions including speech and swallowing. Despite advancements in treatment, 5-year survival rates for mucosal malignancies remain below 70%. Effective prevention of HNSCC demands an understanding of the molecular pathways of carcinogenesis. Specifically, defining features of pre-cancerous dysplastic lesions that indicate a better or worse prognosis is necessary to help identify patients who are likely to develop a carcinoma and allow a more aggressive approach to management. There remains a need for identification of biomarkers that can provide both early prognostic and predictive value in clinical decision-making by serving as both therapeutic targets as well as predictors of therapy response. Here, we comprehensively review the most frequently altered molecular biomarkers of malignant transformation in head and neck dysplasia. These markers are involved in a wide range of cellular processes in head and neck carcinogenesis, including extracellular matrix degradation, cell motility and invasion, cell-cell adhesion, solute transport, immortalization, metabolism, the cell cycle and apoptosis, transcription, and cell signaling.

Evolutionary Relationships Between Dysregulated Genes in Oral Squamous Cell Carcinoma and Oral Microbiota

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers in the world. Changes in the composition and abundance of oral microbiota are associated with the development and metastasis of OSCC. To elucidate the exact roles of the oral microbiota in OSCC, it is essential to reveal the evolutionary relationships between the dysregulated genes in OSCC progression and the oral microbiota. Thus, we interrogated the microarray and high-throughput sequencing datasets to obtain the transcriptional landscape of OSCC. After identifying differentially expressed genes (DEGs) with three different methods, pathway and functional analyses were also performed. A total of 127 genes were identified as common DEGs, which were enriched in extracellular matrix organization and cytokine related pathways. Furthermore, we established a predictive pipeline for detecting the coevolutionary of dysregulated host genes and microbial proteomes based on the homology method, and this pipeline was employed to analyze the evolutionary relations between the seven most dysregulated genes (MMP13, MMP7, MMP1, CXCL13, CRISPO3, CYP3A4, and CRNN) and microbiota obtained from the eHOMD database. We found that cytochrome P450 3A4 (CYP3A4), a member of the cytochrome P450 family of oxidizing enzymes, was associated with 45 microbes from the eHOMD database and involved in the oral habitat of Comamonas testosteroni and Arachnia rubra. The peptidase M10 family of matrix metalloproteinases (MMP13, MMP7, and MMP1) was associated with Lacticaseibacillus paracasei, Lacticaseibacillus rhamnosus, Streptococcus salivarius, Tannerella sp._HMT_286, and Streptococcus infantis in the oral cavity. Overall, this study revealed the dysregulated genes in OSCC and explored their evolutionary relationship with oral microbiota, which provides new insight for exploring the microbiota–host interactions in diseases.

Multiple approaches to oral epithelial dysplasia degree analyses: a pilot study

BACKGROUND

Oral epithelial dysplasia (OED) is the presence of cells of an abnormal type within a tissue, which may signify a stage preceding the development of cancer. Our aim was to determine the interrelation between the expression of multiple molecular markers and the histological features of oral dysplasia.

METHODS

Fifteen samples of OED (five for each severity degree) were analyzed through software assisted image cytometry nuclear morphology. p53 (wild-type and mutated form), Bax and Bcl2 expression was immunohistochemically determined, and the gene expression of MMP1, MMP2, MMP9 and hTERT was determined by RT-PCR. The mean, standard deviation, ANOVA and Fisher's Exact Test (P<0.05) were performed.

RESULTS

Our analysis indicated congruence between the software-assisted measurement of nuclear morphology and severity degree. Only five samples were positive to p53-mutated form; and Bax was more expressed than Bcl-2. hTERT expression was significantly expressed in relation to severity, and MMP1 was predominantly expressed, followed by MMP9 and MMP2.

CONCLUSIONS

Our results reinforce that software-assisted measurement is an alternative to severity degree determination. MMP1 is an important marker for severity dysplasia degree; however, the predominant expression of Bax over Bcl-2 suggests that this pro-apoptotic state could be used to minorize the progression, perhaps, as a future therapeutic target.

Understanding the complex pathogenesis of oral cancer: A comprehensive review

The pathogenesis of oral cancer is a complex and multifactorial process that requires a deep understanding of the underlying mechanisms involved in the development and progress of malignancy. The ever-improving comprehension of the diverse molecular characteristics of cancer, the genetic and epigenetic alterations of tumor cells, and the complex signaling pathways that are activated and frequently cross talk open up promising horizons for the discovery and application of diagnostic molecular markers and set the basis for an era of individualized management of the molecular defects underlying and governing oral premalignancy and cancer. The purpose of this article is to review the key molecular concepts that are implicated in oral carcinogenesis, especially focusing on oral squamous cell carcinoma, and to review selected biomarkers that play a substantial role in controlling the so-called "hallmarks of cancer," with special reference to recent advances that shed light on their deregulation during the different steps of oral cancer development and progression.

Estimation of serum and salivary matrix metalloproteinase levels in oral squamous cell carcinoma patients: a systematic review and meta-analysis

Introduction

Matrix metalloproteinases (MMPs) play a pivotal role in the cancer progression, invasion, and angiogenesis.

Aim

This meta-analysis was conducted to evaluate the difference between oral squamous cell carcinoma (OSCC) patients and healthy controls in the serum and salivary MMP levels.

Material and methods

Four databases – Web of Science, PubMed, Scopus, and Cochrane Library – were searched up to March 2019. The pooled standard mean difference (SMD) and 95% confidence interval (CI) were obtained to explain the difference between the patients and controls in the salivary and serum MMP levels. Both Egger’s and Begg’s tests were considered as the significant publication bias.

Results

Thirteen case-control studies were included in the meta-analysis. Among the analyses of serum MMP levels, the serum MMP7 (SMD = 0.78; 95% CI: 0.15–1.41; p = 0.02) and MMP9 (SMD = 1.18; 95% CI: 0.51–1.84; p = 0.0005) levels were significantly higher in the OSCC patients than in the controls. In addition, the analyses of salivary MMP levels showed that the MMP1 (SMD = 0.46; 95% CI: 0.22–0.70; p = 0.0001) and MMP9 (SMD = 0.66; 95% CI: 0.19–1.12; p = 0.005) levels were significantly higher in the OSCC patients than in the controls.

Conclusions

The meta-analysis showed that the serum MMP7 and MPP9 levels as well as the salivary MMP1 and MPP9 levels were significantly higher in the OSCC patients than in the controls.

Evaluation of the presence of myofibroblasts and matrix metalloproteinase 1 expression in the stroma of oral verrucous hyperplasia and verrucous carcinoma

Background

Oral verrucous carcinoma is a low-grade subtype of oral squamous cell carcinoma that should be differentiated from oral verrucous hyperplasia, a premalignant lesion. Stromal activated myofibroblasts known as cancer-associated fibroblasts have an active role in the initiation and progression of the cancers via secretion of different molecules including matrix metalloproteinases.

Aims

This study is designed to understand the differences in the presence of myofibroblasts and expression of matrix metalloproteinase-1 in the adjacent stroma of verrucous carcinoma and oral verrucous hyperplasia (OVH).

Settings and Design

Cross-sectional study.

Material and Methods

Twenty-seven OVH, 19 oral verrucous carcinoma (OVC), and 8 cutaneous verrucous carcinoma (CVC) specimens were analyzed for immunohistochemical (IHC) expression of α-smooth muscle actin (αSMA) and MMP-1.

Results

IHC studies for αSMA expression in nonvascular stromal cells of the adjacent stroma revealed mild or no expression in 81.4%, 73.7%, and 62.5% of the cases of OVH, OVC, and CVC groups, respectively. No significant difference was seen in αSMA expression index between OVH and OVC groups (Adj. Sig. = 0.220) and between OVC and CVC groups (Adj. Sig. = 1.00). Pairwise analysis revealed a significant difference in MMP-1 expression index between the groups. No significant correlation was observed between MMP-1 expression index and αSMA expression index in OVH (pv = 0.358) and OVC (pv = 0.388) groups.

Conclusion

The differences in MMP-1 expression between OVH and OVC can be used as an adjunctive aid in challenging cases including disoriented or inadequate samples.

Genes and pathways monotonically dysregulated during progression from normal through leukoplakia to gingivo-buccal oral cancer

Oral squamous cell carcinoma of the gingivo-buccal region (OSCC-GB) accounts for the highest cancer morbidity and mortality among men in India. It has been observed that about one-third of individuals with oral leukoplakia, a dysplastic precancerous lesion in the oral cavity, progress to oral cancer. We aimed to identify systematic transcriptomic changes as a normal tissue in the oral cavity progresses to frank OSCC-GB. Seventy-two OSCC-GB patients, from multiple hospitals, were recruited, and transcriptome analysis of tumor and adjacent normal tissue (of all patients) and adjacent leukoplakia tissue (of a subset of 25 unselected patients with concomitant leukoplakia) was performed. We have identified many differences in the transcriptomic profiles between OSCC-GB and squamous cell carcinoma of the head and neck regions. Compared to the normal/precancerous tissue, significant enrichment of ECM−receptor interaction, PI3K-Akt signaling, cytokine−cytokine receptor interaction, focal adhesion, and cell cycle pathways were observed in OSCC-GB. Using gene set enrichment analysis, we identified a profound role of interferon receptor signaling in tumor growth by activating immune evasion mechanisms. The role of tumor-infiltrating immune cells further supported the growth and immunosuppressive mechanism of tumor tissues. Some immune evasion genes—CD274, CD80, and IDO1—were found to be activated even in the precancerous tissue. Taken together, our findings provide a clear insight into the sequential genetic dysregulation associated with progression to oral cancer. This insight provides a window to the development of predictive biomarkers and therapeutic targets for gingivo-buccal oral cancer.

Oral potentially malignant disorders: A scoping review of prognostic biomarkers

This scoping review aimed to map evidence regarding biomarkers for malignant transformation of oral potentially malignant disorders (OPMD). Seventy-three longitudinal studies investigating prognostic biomarkers for OPMD malignant transformation were included, encompassing 5612 disorders and 108 biomarkers, of which 72 were investigated by immunohistochemistry. Most biomarkers were assessed in one or two studies, while five (p53, Ki-67, podoplanin, p16, and DNA ploidy) were analyzed in five or more studies. All studies investigating podoplanin (n = 8) reported a significant association between positive/high immunoexpression and malignant transformation. Similarly, all studies assessing DNA ploidy (n = 5) found that aneuploidy or gross genomic aberrations were significantly associated with malignant transformation. Included studies often presented mixed data from different OPMD subtypes, inadequate description of population characteristics, and lack of adjusted analysis for confounding factors. One hundred and eight biomarkers were identified and, from these, podoplanin immunoexpression and DNA ploidy were considered promising candidates for future long-term clinical research.

Differential in vitro sensitivity of oral precancerous and squamous cell carcinoma cell lines to 5-aminolevulinic acid-mediated photodynamic therapy

OBJECTIVES

The clinical effect of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) may be correlated with the degree of dysplasia of cancer tissues, but much is still unknown regarding the differences in its effectiveness, especially in oral cancer and precancerous lesions. The aim of this study is to compare the effects of ALA-PDT on a human oral precancerous cell line (DOK) and an oral squamous cell carcinoma cell line (CAL-27).

METHODS

First, we explored the dose- and time-dependent responses of DOK and CAL-27 cells to ALA-PDT. DOK and CAL-27 cells were incubated with various concentrations of ALA (from 0.25 to 2 mM), followed by PDT using laser irradiation at 635 nm. The resulting photocytotoxicity was assessed in both cell lines using MTT assays. Further, apoptosis was assessed using flow cytometry, reactive oxygen species (ROS) generation was evaluated with 2,7-dichlorofluorescein diacetate (DCFH2-DA), and the response to treatment was examined via RT-qPCR and Western blotting to measure the mRNA and protein expression levels of matrix metallopeptidase 2 (MMP-2) and MMP-9.

RESULTS

ALA-PDT inhibited the proliferation of DOK and CAL-27 cells in a dose- and time-dependent manner. Dose-effect and inhibition-time relationships were also found. The rates of DOK and CAL-27 cell apoptosis when the ALA dose was 1 mM were 30.66 ± 3.10% and 75.40 ± 1.29%, respectively (P < 0.01). Following PDT, compared with DOK cells, the ROS level in CAL-27 cells was significantly increased and was correlated with an increase in the ALA concentration. Mechanistically, both the mRNA and protein expression levels of MMP-2 and MMP-9 were found to be regulated in both cell types after ALA-PDT.

CONCLUSION

ALA-PDT effectively killed DOK and CAL-27 cells in a dose- and time-dependent manner in vitro. However, under the same conditions, the susceptibilities of these cell lines to ALA-PDT were different. Further studies are necessary to confirm whether this difference is present in clinical oral cancer and precancerous lesions.

Matrix metalloproteinase 9 inhibits the motility of highly aggressive HSC-3 oral squamous cell carcinoma cells

Pro-tumorigenic activities of matrix metalloproteinase (MMP) 9 have been linked to many cancers, but recently the tumour-suppressing role of MMP9 has also been elucidated. The multifaceted evidence on this subject prompted us to examine the role of MMP9 in the behaviour of oral tongue squamous cell carcinoma (OTSCC) cells. We used gelatinase-specific inhibitor, CTT2, and short hairpin (sh) RNA gene silencing to study the effects of MMP9 on proliferation, motility and invasion of an aggressive OTSCC cell line, HSC-3. We found that the migration and invasion of HSC-3 cells were increased by CTT2 and shRNA silencing of MMP9. Proliferation, in turn, was decreased by MMP9 inhibition. Furthermore, arresten-overexpressing HSC-3 cells expressed increased levels of MMP9, but exhibited decreased motility compared with controls. Interestingly, these cells restored their migratory capabilities by CTT2 inhibition of MMP9. Hence, although higher MMP9 expression could give rise to an increased tumour growth in vivo due to increased proliferation, in some circumstances, it may participate in yet unidentified molecular mechanisms that reduce the cell movement in OTSCC.

"Omics" in oral cancer: New approaches for biomarker discovery

OBJECTIVES

In this review paper, we explored the application of "omics" approaches in the study of oral cancer (OC). It will provide a better understanding of how "omics" approaches may lead to novel biomarker molecules or molecular signatures with potential value in clinical practice. A future direction of "omics"-driven research in OC is also discussed.

METHODS

Studies on "omics"-based approaches [genomics/proteomics/transcriptomics/metabolomics] were investigated for differentiating oral squamous cell carcinoma,oral sub-mucous fibrosis, oral leukoplakia, oral lichen planus, oral erythroplakia from normal cases. Electronic databases viz., PubMed, Springer, and Google Scholar were searched.

RESULTS

One eighty-one studies were included in this review. The review shows that the fields of genomics, transcriptomics, proteomics, and metabolomics-based marker identification have implemented advanced tools to screen early changes in DNA, RNA, protein, and metabolite expression in OC population.

CONCLUSIONS

It may be concluded that despite advances in OC therapy, symptomatic presentation occurs at an advanced stage, where various curative treatment options become very limited. A molecular level study is essential for detecting an OC biomarker at an early stage. Modern "Omics" strategies can potentially make a major contribution to meet this need.

The interplay of matrix metalloproteinase-8, transforming growth factor-β1 and vascular endothelial growth factor-C cooperatively contributes to the aggressiveness of oral tongue squamous cell carcinoma

Background:

Matrix metalloproteinase-8 (MMP-8) has oncosuppressive properties in various cancers. We attempted to assess MMP-8 function in oral tongue squamous cell carcinoma (OTSCC).

Methods:

MMP-8 overexpressing OTSCC cells were used to study the effect of MMP-8 on proliferation, apoptosis, migration, invasion and gene and protein expression. Moreover, MMP-8 functions were assessed in the orthotopic mouse tongue cancer model and by immunohistochemistry in patient samples.

Results:

MMP-8 reduced the invasion and migration of OTSCC cells and decreased the expression of MMP-1, cathepsin-K and vascular endothelial growth factor-C (VEGF-C). VEGF-C was induced by transforming growth factor-β1 (TGF-β1) in control cells, but not in MMP-8 overexpressing cells. In human OTSCC samples, low MMP-8 in combination with high VEGF-C was an independent predictor of poor cancer-specific survival. TGF-β1 treatment also restored the migration of MMP-8 overexpressing cells to the level of control cells. In mouse tongue cancer, MMP-8 did not inhibit metastasis, possibly because it was eliminated in the peripheral carcinoma cells.

Conclusions:

The suppressive effects of MMP-8 in OTSCC may be mediated through interference of TGF-β1 and VEGF-C function and altered proteinase expression. Together, low MMP-8 and high VEGF-C expression have strong independent prognostic value in OTSCC.

Salivary MMP-1, MMP-2, MMP-3 and MMP-13 Levels in Patients with Oral Lichen Planus and Squamous Cell Carcinoma

The aim of present study was to evaluate salivary matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-3 and MMP-13 levels in patients with oral lichen planus (OLP) and squamous cell carcinomas (SCC) as well as in healthy controls. Thirty cases of OLP (bilateral lesions, papular and reticular lesions, and Wickham lines) clinically and histopathologically (group A), 30 with oral SCCs (group B), and 30 with no history of oral cancer, other lesions or lichen planus (group C) were enrolled at the Department of Oral Medicine School of Dentistry, Zahedan, Iran. Unstimulated whole saliva was collected and laboratory measurement of salivary concentration of MMP-1, MMP-2, MMP-3 and MMP-13 was conducted by immuno-sorbent enzyme-linked methods. Data analysis was performed with Kruskal-Wallis and Mann-Whitney tests and Pearson’s correlation coefficients. In the present study, MMP-2 and MMP-13 levels were higher in oral SCC patients than in OLP and healthy individuals. More research is required to assess MMP links with tumor invasion.

Anatomy-Based Algorithms for Detecting Oral Cancer Using Reflectance and Fluorescence Spectroscopy

Objective

We used reflectance and fluorescence spectroscopy to noninvasively and quantitatively distinguish benign from dysplastic/malignant oral lesions. We designed diagnostic algorithms to account for differences in the spectral properties among anatomic sites (gingiva, buccal mucosa, etc).

Methods

In vivo reflectance and fluorescence spectra were collected from 71 patients with oral lesions. The tissue was then biopsied and the specimen evaluated by histopathology. Quantitative parameters related to tissue morphology and biochemistry were extracted from the spectra. Diagnostic algorithms specific for combinations of sites with similar spectral properties were developed.

Results

Discrimination of benign from dysplastic/malignant lesions was most successful when algorithms were designed for individual sites (area under the receiver operator characteristic curve [ROC-AUC], 0.75 for the lateral surface of the tongue) and was least accurate when all sites were combined (ROC-AUC, 0.60). The combination of sites with similar spectral properties (floor of mouth and lateral surface of the tongue) yielded an ROC-AUC of 0.71.

Conclusions

Accurate spectroscopic detection of oral disease must account for spectral variations among anatomic sites. Anatomy-based algorithms for single sites or combinations of sites demonstrated good diagnostic performance in distinguishing benign lesions from dysplastic/malignant lesions and consistently performed better than algorithms developed for all sites combined.

Upregulated expression of MMP-9 in gingival epithelial cells induced by prolonged stimulation with arecoline

Betel quid chewing is implicated in the high prevalence of oral cancer in Southeast Asian countries. One of the major components of betel quid is arecoline. In the present study, in order to characterize the association between chronic arecoline stimulation and carcinogenesis the expression level of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 mRNA in human gingival epithelial progenitor cells (HGEPs) stimulated with arecoline was assessed. The HGEPs were alternated between 3 days of incubation with arecoline (50 µg/ml), and 3 days without arecoline, for up to 30 days. The expression levels of the MMPs and TIMPs in the cells stimulated with arecoline were evaluated by reverse transcription-quantitative polymerase chain reaction at 18 and 30 days. The expression of MMP-9 mRNA in the experimental group was significantly increased compared with in the control group (P<0.01). No significant differences in the expression of MMP-2, TIMP-1 or TIMP-2 mRNA were observed between the experimental and control groups. Using an MMP-9 activity assay, the levels of MMP-9 activity in the experimental group were demonstrated to be significantly higher than in the control group (P<0.05). To investigate associated cellular signaling pathways, PDTC [a nuclear factor (NF)-κB/inhibitor of NF-κB (IκB) inhibitor], PD98059 [a mitogen-activated protein kinase kinase (MAPKK)1 and MAPKK2 inhibitor], SB203580 (a p38 MAPK inhibitor) and 5,15-DPP [a signal transduction and activator of transcription (STAT) 3 inhibitor] were used. All inhibitors decreased the extent of MMP-9 upregulation induced by stimulation with arecoline. Based on the data, it is hypothesized that MMP-9 activity may be involved in the pathological alterations of oral epithelium induced by betel quid chewing, and that the NF-κB/IκB, MAPK, p38 MAPK and STAT3 signaling pathways may be involved in the production of MMP-9 induced by betel quid chewing.

Serum and salivary levels of chemerin and MMP-9 in oral squamous cell carcinoma and oral premalignant lesions

OBJECTIVE

The objective of this study was to investigate serum and salivary levels of chemerin and MMP-9 as early diagnostic biomarkers for patients with oral premalignant lesions (OPMLs) and oral squamous cell carcinoma (OSCC).

METHODS

This study included 45 individuals; 15 healthy control, 15 patients with OPMLs, and 15 patients with early stage OSCC. Chemerin and MMP-9 were determined in serum and saliva samples utilizing enzyme-linked immunosorbent assays.

RESULTS

Serum and salivary levels of chemerin and MMP-9 in patients with OSCC were significantly higher than OPMLs and control group. Patients with OPMLs showed also elevated profiles for serum and salivary chemerin and MMP-9 compared to control group. Receiver operator characteristic curve analysis revealed that all tested biomarkers have 100 % sensitivity and 100 % specificity with area under the curve (AUC) of 1.00 in detecting early stage OSCC and OPMLs. In distinguishing OSCC from OPMLs, salivary MMP-9, serum chemerin, and salivary chemerin showed AUC of 0.99, 0.92, and 0.88, respectively, showing higher sensitivity and specificity compared with serum MMP-9 (AUC; 0.6) which failed to differentiate between the two conditions.

CONCLUSION

Chemerin and MMP-9 might be considered as salivary diagnostic biomarkers for OPMLs and early detection of OSCC and also for detecting early cancerization of OPMLs.

CLINICAL RELEVANCE

This research implied that salivary chemerin was a novel diagnostic factor for patients with OPML and early stage OSCC patients, and chemerin could be a new therapeutic target for regulating cancer angiogenesis and blocking malignization of OPMLs.

Can MMP-9 be a Prognosticator Marker for Oral Squamous Cell Carcinoma?

INTRODUCTION

Invasion and metastasis of malignant tumours severely endanger the life of cancer patients. Squamous cell carcinoma is one of the commonly found malignancies in the oral cavity and its survival rate has not improved from past few decades. Since an important risk factor for oral squamous cell carcinoma is the presence of epithelial dysplasia, it is necessary to check the presence of a prognosticator marker in both of them. As matrix metalloproteinase's (MMP's) are involved in degradation of type IV collagen, which are one of the important components of extracellular matrix components which play a relevant role in several steps of tumour progression such as invasion and metastasis. We have studied MMP-9 expression to evaluate its prognostic potential in oral cancers as well as oral epithelial dysplasia along with tissues of normal oral epithelium.

MATERIALS AND METHODS

The expression was examined using immunohistochemistry procedure with MMP-9 in 100 samples including cases of epithelium from normal oral mucosa, oral dysplastic lesions and oral squamous cell carcinoma. One set of formalin fixed, paraffin embedded sections of the three categories were stained by haematoxylin and eosin. The sections were then evaluated under microscope. Data was examined for statistical significance using SPSS 13.0 by Mann-Whitney Test and Kruskal-Wallis Test.

RESULTS

With MMP-9 gain of expression was noted from Control group to oral squamous cell carcinoma. Cytoplasmic staining was seen with MMP-9. Statistically highly significant differences were seen between oral epithelial dysplasia and oral squamous cell carcinoma and statistically significant differences were found between the control group and the oral squamous cell carcinoma group.

CONCLUSION

This study suggested that oral squamous cell carcinoma shows higher MMP-9 expression as compared to oral epithelial dysplasia followed by epithelium from normal oral mucosa. However, no correlation was found among the histological grades of oral squamous cell carcinoma.

Biomarkers in saliva for the detection of oral squamous cell carcinoma and their potential use for early diagnosis: a systematic review

Objective To determine the capacity of salivary biomarkers in the early diagnosis of oral squamous cell carcinoma. Study design A systematic review of the literature was performed based on the English titles listed in the PubMed, EBSCO, Cochrane, Science Direct, ISI web Science and SciELO databases using the following search descriptors: Oral cancer, diagnosis, biomarkers, saliva and oral squamous cell carcinoma. Abstracts and full-text articles were assessed independently by two reviewers. International checklists for assessment of methodological quality were used. Levels of evidence and grades of recommendation through the Scottish Intercollegiate Guidelines Network (SIGN) template were recognized. The units of analysis were identified through a reference matrix. Results Through the research strategy and after application of different filters and considering choosing criteria, six studies were obtained for analysis. Salivary biomarkers for oral cancer most frequently found were mRNA and proteins for IL-8, CD44, MMP-1 and MMP-3. New peptide-biomarkers such as Cyfra 21-1 and ZNF510 were found. ZNF 510 was the only biomarker which increased in the population with tumour stage T1 + T2 and T3 + T4. Only one study showed a sensitivity and specificity of 96% when the biomarker ZNF 510 is employed to discriminate early and late tumour stages. Conclusions There is no sufficient scientific evidence to support the capacity of the identified salivary biomarkers for the early diagnosis of oral cancer (sub-clinical stages of the pathogenic period before cancer phenotypes are manifested). Salivary biomarkers, however, may be employed to discriminate between healthy and cancer patients.

Modulating Effect of Enicostemma littorale on the Expression Pattern of Apoptotic, Cell Proliferative, Inflammatory and Angiogenic Markers During 7, 12-Dimethylbenz (a) Anthracene Induced Hamster Buccal Pouch Carcinogenesis

Enicostemma littorale leaves are traditionally used for the treatment of several diseases, including inflammation and cancer. This study has taken effort to explore the antitumor initiating potential of E. littorale leaves (ElELet) by analyzing the expression pattern of apoptotic (p53, Bcl-2 and Bcl-2 associated X-protein), cell-proliferative (cyclin D1 and proliferating cell nuclear antigen), angiogenic (vascular endothelial growth factor), invasive (matrix metalloproteinase-2 and 9), and inflammatory (NF-κB and cyclooxygenase-2) markers during 7, 12-dimethylbenz (a) anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Oral tumors were induced in the buccal pouches of hamsters using the potent site and organ specific carcinogen, DMBA. DMBA application 3 times a week for 14 weeks resulted in tumor formation in the buccal pouches. Hundred percent tumor formations with dysregulation in the expression pattern of apoptotic, cell proliferative, inflammatory, angiogenic, and invasive markers were observed in the buccal pouches of hamsters treated with DMBA alone. ElELet at a dose of 250 mg/kg body weight orally to DMBA treated hamsters significantly prevented the tumor formation as well as corrected the abnormalities in the expression pattern of above mentioned molecular markers. ElELet thus modulated the expression pattern of all the above mentioned molecular markers in favor of the suppression of cell proliferation occurring in DMBA induced hamster buccal pouch carcinogenesis.

BMP-2 promotes oral squamous carcinoma cell invasion by inducing CCL5 release

Bone morphogenetic protein-2 (BMP-2)-containing bone grafts are useful regenerative materials for oral and maxillofacial surgery; however, several in vitro and in vivo studies previously reported cancer progression-related adverse effects caused by BMP-2. In this study, by quantifying the rhBMP-2 content released from bone grafts, the rhBMP-2 concentration that did not show cytotoxicity in each cell line was determined and applied to the in vitro monoculture or coculture model in the invasion assay. Our results showed that 1 ng/ml rhBMP-2, while not affecting cancer cell viability, significantly increased the invasion ability of the cancer cells cocultured with fibroblasts. Cocultured medium with rhBMP-2 also contained increased levels of matrix metalloproteinases. rhBMP-2-treated cocultured fibroblasts did not show a prominent difference in mRNA expression profile. Some cytokines, however, were detected in the conditioned medium by a human cytokine antibody array. Among them, the cancer invasion-related factor CCL5 was quantified by ELISA. Interestingly, CCL5 neutralizing antibodies significantly reduced the invasion of oral cancer cells. In conclusion, our results suggest that 1 ng/ml rhBMP-2 may induce invasion of oral squamous cell carcinoma (OSCC) cells by CCL5 release in coculture models. Therefore, we propose that a careful clinical examination before the use of rhBMP-2-containing biomaterials is indispensable for using rhBMP-2 treatment to prevent cancer progression.

Identification of human papillomavirus status specific biomarker in head and neck cancer

BACKGROUND

In an attempt to improve the prognosis of patients with head and neck cancer, it could be necessary to identify biomarkers in homogeneous subgroups of patients with head and neck cancer.

METHODS

We explored the necessity of human papillomavirus (HPV) status-specific biomarkers in patients with head and neck cancer and identified an HPV status-specific gene set. The identified gene set was validated with the external microarray datasets. For this purpose, we used 4 microarray datasets obtained from a public database. One dataset was used for identifying the HPV status specific gene set, and the other datasets were used for validation.

RESULTS

The identified gene set for distinguishing head and neck cancer from head and neck normal, did not accurately discriminate the HPV specific patients with head and neck cancer from the head and neck normal group. Also, it was demonstrated that some HPV-positive (HPV+) head and neck cancer-specific genes may not be significant in HPV-negative (HPV-) head and neck cancer patients. The identified HPV specific gene sets showed good performance in validation datasets. The HPV+ head and neck cancer-specific gene set included various metabolism-related pathways, and the HPV- head and neck cancer-specific gene set included several pathways; fibroblast, collagen degradation, actin-binding, and actin cytoskeleton.

CONCLUSION

The identification of HPV status-specific significant gene set was necessary. It is expected that HPV status-specific biomarkers can be helpful in deciding therapeutic methods for patients with head and neck cancer, after biological validation and large prospective trials.

Salivary biomarkers for detection of oral squamous cell carcinoma - current state and recent advances

Oral squamous cell carcinoma (OSCC) is the most common malignant neoplasm of the oral cavity. Detection of OSCC is currently based on thorough clinical oral examination combined with biopsy for histological analysis. Most cases of OSCC are not detected until the cancer has developed into advanced stages; thus, a reliable early stage diagnostic marker is needed. This literature review presents an overview of the status of current advances in salivary diagnostics for OSCC. Though many protein and mRNA salivary biomarkers have been identified that can detect OSCC with high sensitivity and specificity, the most discernable findings occur with the use of multiple markers. Studies that incorporate proteomic, transcriptomic, and potentially additional "omics", including methylomics, need to be initiated to bring technology to clinical applications and allow the best use of saliva in diagnosing OSCC.

Can immunohistochemistry serve as an alternative to subjective histopathological diagnosis of oral epithelial dysplasia?

Many attempts have been made to identify objective molecular biomarkers to diagnose and prognosticate oral epithelial dysplasia (OED) because histopathological interpretation is subjective and lacks sensitivity. The majority of these efforts describe changes in gene expression at protein level in OED as determined by immunohistochemistry (IHC). However, the literature on these putative markers of oral cancer progression is vast and varied. The main purpose of this article is to review current knowledge on biomarkers of protein expression for OED by IHC approaches. We further discuss these findings in terms of the proposed essential hallmarks of cancer cells to better understand their role in oral oncogenesis.

Reflux induces DNA strand breaks and expression changes of MMP1+9+14 in a human miniorgan culture model

Gastroesophageal reflux disease has been implicated in the pathogenesis of adenocarcinoma of the oesophagus. The same applies to laryngopharyngeal reflux (LPR) and squamous cell cancer of the head and neck, but so far, this link has not been proven. The impact of low pH and bile acids has not been studied extensively in cells other than oesophageal cancer cell lines and tissue. The aims of this study were to investigate the pathogenic potential of reflux and its single components on the mucosa of the upper respiratory tract. We measured DNA stability in human miniorgan cultures (MOCs) and primary epithelial cell cultures (EpCs) in response to reflux by the alkaline comet assay. As matrix metalloproteinases (MMPs) are involved in extracellular matrix remodelling processes and may contribute to cancer progression, we studied the expression of MMP1, -9, and -14 in MOCs, EpC, UM-SCC-22B, and FADUDD. DNA strand breaks (DNA-SBs) increased significantly at low pH and after incubation with human or artificial gastric juice. Single incubation with glycochenodeoxycholic acid also showed a significant increase in DNA-SBs. In epithelial cell cultures, human gastric juice increased the number of DNA-SBs at pH 4.5 and 5.5. Artificial gastric juice significantly up regulated the gene expression of MMP9. Western blot analysis confirmed the results of gene expression analysis, but the up regulation of MMP1, -9, and -14 was donor-specific. Reflux has the ability to promote genomic instability and may contribute to micro environmental changes suitable for the initiation of malignancy. Further functional gene analysis may elucidate the role of laryngopharyngeal reflux in the development of head neck squamous cell carcinoma (HNSCC).

Functional polymorphisms of matrix metalloproteinase-9 and survival in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy

To investigate the prognostic role of major matrix metalloproteinase (MMP) gene polymorphisms in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) treated with chemoradiotherapy. Four hundred twenty-one consecutive NPC patients were prospectively recruited. Two hundred patients were randomly selected as the training cohort, and the remaining 221 patients were the validation cohort. Twelve polymorphisms in the MMP-1, 2, 3, 7, 8, and 9 genes were genotyped by ligase detection reaction-PCR. MMP-9 rs2250889 PR/RR (HR = 2.287, 95% CI 1.400-3.735) and rs17576 RQ/QQ (HR = 2.347, 95% CI 1.431-3.849) genotypes were significantly related with increased death risk in the training cohort. Analysis of the validation cohort confirmed these results (rs2250889: HR = 2.231, 95% CI 1.281-3.886; rs17576: HR = 2.987, 95% CI 1.674-5.330). Multivariate analysis showed that rs17576 (HR = 2.284, 95% CI 1.123-4.643, P = 0.023) was still an independent prognostic factor. The MMP-9 rs17576 is a novel independent prognostic marker in patients with locoregionally advanced NPC treated with chemoradiotherapy.

Matrix metalloproteinase-9 (mmp-9) expression in different subtypes of ameloblastoma

BACKGROUND

Ameloblastoma is a common benign odontogenic tumor of the jaw with a local invasive and highly destructive behavior and can develop in any age, with peak prevalence in 3rd-4th decade. Ameloblastoma can be divided into six histological types: follicular, plexiform, acanthomatous, desmoplastic, granular, and basal cell. Matrix metalloproteinase-9 (MMP-9) (92-kD gelatinase/type IV collagenases = gelatinase B) is involved in bone resorption by degradation of extracellular matrix and osteoclasts recruitment. Recent studies have found that MMP-9 is expressed by ameloblastoma and has a role in ameloblastoma local invasiveness.

OBJECTIVE

To analyze MMP-9 expression between different histological types of ameloblastoma.

MATERIAL AND METHOD

Forty samples of ameloblastoma were collected through consecutive sampling and the MMP-9 expression was detected using immunohistochemistry.

RESULT

All samples showed positive MMP-9 expression with moderate to strong intensity. 82.4 % plexiform type and 83.3 % mixed type have strong immunoexpression, significantly different with follicular type with only 36.4 % (P < 0.05).

CONCLUSION

Ameloblastoma plexiform and mixed type have higher MMP-9 expression than ameloblastoma follicular type. Different MMP-9 expression may contribute in different ameloblastoma biological behavior.

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.

The immunohistochemical characterization of MMP-2, MMP-10, TIMP-1, TIMP-2, and podoplanin in oral squamous cell carcinoma

OBJECTIVES

The aim of this study was to immunohistochemically evaluate the expression of matrix metalloproteinase (MMP)-1, MMP- 2, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, and podoplanin in oral squamous cell carcinoma (OSCC). Immunohistochemical staining of podoplanin-positive lymphatic vessel density (LVD) was also assessed.

STUDY DESIGN

Forty cases of OSCC were analyzed by immunohistochemistry.

RESULTS

MMP-2, MMP-10, TIMP-1, TIMP-2, and podoplanin were detected in each of the 40 OSCC cases. The expression of MMP-2 was significantly correlated with histologic grade. The expression of podoplanin was positively correlated with gender and negatively correlated with tumor size. A significant positive correlation was also detected between LVD and the presence of lymph node metastases, gender, age, and diameter of the lymph node (if involved), as well as histologic grade.

CONCLUSIONS

The results are suggestive of important roles that MMP-2, MMP-10, TIMP-2, and podoplanin play in pathologic processes of OSCC, including invasion. Our findings also suggest that LVD may play a role in lymphatic metastasis and tumor progression.

Comparative analysis of basal lamina type IV collagen α chains, matrix metalloproteinases-2 and -9 expressions in oral dysplasia and invasive carcinoma

The aim of this study was to compare the expressions of basal lamina (BL) collagen IV α chains and matrix metalloproteinases (MMP)-2 and MMP-9 in oral dysplasia (OED) and invasive carcinoma. Ten cases each of OEDs, carcinomas-in situ and oral squamous cell carcinomas (OSCCs) were examined by immunohistochemistry. Another 5 cases, each of normal and hyperplastic oral mucosa, served as controls. Results showed that α1(IV)/α2(IV) and α5(IV)/α6(IV) chains were intact in BLs of control and OEDs. In BLs of carcinoma-in situ, α1(IV)/α2(IV) chains preceded α5(IV)/α6(IV) chains in showing incipient signs of disruption. OSCCs exhibited varying degrees of collagen α(IV) chain degradation. MMP-2 and MMP-9 were absent in controls and OED, but weakly detectable in carcinoma-in situ. In OSCC, these proteolytic enzymes were expressed in areas corresponding to collagen α(IV) chain loss. Enzymatic activity was enhanced in higher grade OSCC, and along the tumor advancing front. Overall the present findings suggest that loss of BL collagen α(IV) chains coincided with gain of expression for MMP-2 and MMP-9, and that these protein alterations are crucial events during progression from OED to OSCC.

Urban legends series: oral leukoplakia

To date, the term oral leukoplakia (OL) should be used to recognize 'predominantly white plaques of questionable risk, having excluded (other) known diseases or disorders that carry no increased risk of cancer'. In this review, we addressed four controversial topics regarding oral leukoplakias (OLs): (i) Do tobacco and alcohol cause OLs?, (ii) What percentage of OLs transform into oral squamous cell carcinoma (OSCC)?, (iii) Can we distinguish between premalignant and innocent OLs?, and (iv) Is proliferative verrucous leukoplakia (PVL) a specific entity or just a form of multifocal leukoplakia? Results of extensive literature search suggest that (i) no definitive evidence for direct causal relationship between smoked tobacco and alcohol as causative factors of OLs, (ii and iii) the vast majority of OLs follow a benign course and do not progress into a cancer, and no widely accepted and/or validated clinical and/or biological factors can predict malignant transformation, and (iv) the distinction between multifocal/multiple leukoplakias and PVL in their early presentation is impossible; the temporal clinical progression and the high rate of recurrences and development of cancer of PVL are the most reliable features for diagnosis.

Fluctuating roles of matrix metalloproteinase-9 in oral squamous cell carcinoma

One hallmark of cancer is the degradation of the extracellular matrix (ECM), which is caused by proteinases. In oral cancers, matrix metalloproteinases (MMPs), especially MMP-9, are associated with this degradation. MMPs break down the ECM allowing cancer to spread; they also release various factors from their cryptic sites, including cytokines. These factors modulate cell behavior and enhance cancer progression by regulating angiogenesis, migration, proliferation, and invasion. The development of early metastases is typical for oral cancer, and increased MMP-9 expression is associated with a poor disease prognosis. However, many studies fail to relate MMP-9 expression with metastasis formation. Contrary to earlier models, recent studies show that MMP-9 plays a protective role in oral cancers. Therefore, the role of MMP-9 is complicated and may fluctuate throughout the different types and stages of oral cancers.

Matrix metalloproteinase gene polymorphisms and oral cancer

Since oral squamous cell carcinoma (OSCC) is the most prevalent malignant cancer in the oral cavity, several researches have been performed to study the role of important enzymes in this disease. Among them, the matrix metalloproteinases (MMPs) are highlighted, due to the fact that they are proteinases responsible to degrade many extra-cellular matrix components, making possible the invasion of neoplasic cells. Important tools in cancer prognosis have been utilized aiming to correlate high levels of MMPs and OSCC, such as immunohistochemical, zymographic and mRNA detection methods. However, these techniques are usually applied after cancer detection, characterizing a curative but not a preventive medicine. Trying to make interventions before the development of the disease and making possible the identification of people at high risk and, analysis of modifications in MMP genes has been a chance for modern medicine. Recently, polymorphisms in MMP genes have been related to different neoplasias, including OSCC. Despite investigation is beginning, MMP gene polymorphisms seems to have a promising future in oral cancer research and some of the present results have shown that there are MMP polymorphisms related to an increased risk for developing oral cancer. Key words:Oral cancer, polymorphism, matrix metalloproteinase.

Immunoexpression of matrix metalloproteinases and their inhibitors in different areas of oral squamous cell carcinoma

BACKGROUND

Several studies have shown the participation of MMPs in oral squamous cell carcinoma, the most frequent malignant neoplasm of the oral cavity. The expression of some MMPs correlates with a more aggressive biological behaviour. The objective of this study was to determine which MMPs and TIMPs were expressed in both neoplastic and peritumoural stromal cells in different histopathology areas.

METHODS

Patients who underwent primary tumour neck dissection for oral squamous cell carcinoma were included. Immunoexpression of MMP-1, -2, -3, -7, -9, -11, -13, and TIMP-1 and -2 in different areas of pathologic specimens (in situ carcinoma, primary tumour, invasive front, distant invasion carcinoma, and lymph node metastasis) was evaluated. Enzyme expression on mucosa adjacent to tumour served as control.

RESULTS

Thirty cases were included. Only 6 MMPs and 1 TIMP were expressed in the studied areas. Statistically significant differences in the number of cases with positive MMPs or TIMP expression, in both neoplastic and peritumoural cells, between control and the rest of the areas were observed. MMP-2 expression was constant in the areas with a more aggressive biological behaviour.

CONCLUSIONS

MMP-2 expression may represent a dynamic interaction between host and tumour that favours the establishment of neoplastic cells at distant sites.

MMP-9 polymorphisms are related to serum lipids levels but not associated with colorectal cancer susceptibility in Chinese population

Matrix metalloproteinases (MMPs) play an important role in cancer development and aggression. MMP-9 polymorphisms may affect MMPs expression and contribute to interindividual differences in susceptibility to a wide spectrum of cancers. The purpose of this study was to investigate the association of MMP-9 P574R and R668Q polymorphisms with colorectal cancer (CRC); and to explore the relationship among the polymorphisms and clinicopathologic parameters, serum tumor markers and lipids. The genotypes were determined by polymerase chain reaction-restriction fragment lengthy polymorphism (PCR-RFLP). Tumor markers were measured with the Electro ChemiL uminescence method. Lipids levels were analyzed using an automatic biochemistry analyzer. The both polymorphisms were not associated with the risk of CRC risk. The clinicopathologic parameters, tumor markers were not associated with MMP-9 polymorphisms. Total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were significantly higher in patients with P574R PP genotype compared with patients with P574R PR combined RR genotypes (P = 0.043 and P = 0.038 respectively). Our data suggested that MMP-9 P574R and R668Q were not associated with CRC risk, but P574R affected serum LDL-C and TC levels in CRC patients.

Differential expression patterns of MMPs and their role in the invasion of epithelial premalignant tumors and invasive cutaneous squamous cell carcinoma

Co-expression of several members of the matrix metalloproteinase (MMP) family is characteristic of human malignant tumors. MMP-2, MMP-9, TIMP-2, and MT1-MMP are thought to be involved in the process of destruction of basement membranes and stromal invasion by neoplastic epithelial cells. In this study, we investigated the expression and role of MMPs in cutaneous oncogenesis. Tissue microarray consisting of 62 squamous cell carcinomas (SCC), 32 Bowen's disease (BD) samples, 25 normal epidermis samples were obtained for the study. MMP-2,-9, MT1-MMP and TIMP-2 proteins were examined by immunohistochemical staining and mRNA level was detected by quantitative RT-PCR in fresh tissues consisting of 5 cutaneous SCCs and paired normal epidermis samples. Gelatinase activity of MMP-2 and MMP-9 was investigated by gelatin zymography and protein levels of MT1-MMP and TIMP-2 were measured by western blot in 2 human SCC cell lines. The invasive property was evaluated with invasion assays using Transwell filters. SCC exhibited significantly increased MMP-2, MT1-MMP and decreased TIMP-2 mRNA and protein expression compared to that of the normal epithelium. Immunohistochemical staining revealed that MT1-MMP was strongly expressed on the invasive front of SCCs, whereas BD exhibited higher expression around the dyskeratotic cells in the epithelium. In comparison with the expression observed in BD, SCC exhibited significantly increased MMP-2 expression. In addition, high MMP-2 and MT1-MMP expression and low TIMP-2 expression had a significant positive correlation with the invasiveness of SCC cell lines in vitro. Our results revealed significantly increased MT1-MMP and MMP-2 expression and decreased TIMP-2 expression in cutaneous SCC, and the expression correlated with the invasiveness of SCC cell lines. Therefore, the expression of these factors in cutaneous tumors may serve as an indicator of tumor aggressiveness and invasion.

Clinical significance of molecular alterations in histologically negative surgical margins of head and neck cancer patients

The development of locoregional recurrence is the main reason for treatment failure in head and neck squamous cell carcinomas (HNSCC) and the remaining of tumor cells in surgical margins is associated with recurrence. Surgical margins are considered negative based on histologic assessment of the pathological specimen. However, this method lacks sensitivity in identifying cells that already started malignant transformation but have not yet developed a pathologic phenotype. We investigated the usefulness of assessing the expression of PTHLH, EPCAM, MMP9, LGALS1 and MET for the detection of molecular alterations in histologically negative surgical margins and determine the correlation of these tumor-related alterations with clinical and prognostic parameters. Differential gene expression was determined by quantitative RT-PCR analyses in normal mucosa, HNSCC and negative margin samples. Thirty-eight percent of the histologically negative surgical margins examined were margin-positive for overexpression of at least one of the genes evaluated. Moreover, MMP9 and PTHLH overexpression in the surgical margins was associated with the development of second primary tumors (p=0.002) and lower rates of local control (log rank test p=0.022; HR=4.186; p=0.035), respectively. These findings demonstrate that the overexpression of tumor-related genes in histologically negative surgical margins is a frequent event. The use of qRT-PCR may be an useful tool in detecting actually negative HNSCC surgical margins and the overexpression of specific genes in these margins could be helpful in the identification of patients with a higher risk of developing second primary tumors and local recurrences, thus aiding the surgeon in the delineation of the HNSCC resection extent and helping in the planning of adjuvant therapy.