Oral squamous cell carcinoma is associated with decreased bcl-2/bax expression ratio and increased apoptosis

Enhancing oral squamous cell carcinoma prediction: the prognostic power of the worst pattern of invasion and the limited impact of molecular resection margins

Objective

Oral squamous cell carcinoma (OSCC) originates from the mucosal lining of the oral cavity. Almost half of newly diagnosed cases are classified as advanced stage IV disease, which makes resection difficult. In this study, we investigated the pathological features and mutation profiles of tumor margins in OSCC.

Methods

We performed hierarchical clustering of principal components to identify distinct patterns of tumor growth and their association with patient prognosis. We also used next-generation sequencing to analyze somatic mutations in tumor and marginal tissue samples.

Results

Our analyses uncovered that the grade of worst pattern of invasion (WPOI) is strongly associated with depth of invasion and patient survival in multivariable analysis. Mutations were primarily detected in the DNA isolated from tumors, but several mutations were also identified in marginal tissue. In total, we uncovered 29 mutated genes, mainly tumor suppressor genes involved in DNA repair including BRCA genes; however none of these mutations significantly correlated with a higher chance of relapse in our medium-size cohort. Some resection margins that appeared histologically normal harbored tumorigenic mutations in TP53 and CDKN2A genes.

Conclusion

Even histologically normal margins may contain molecular alterations that are not detectable by conventional histopathological methods, but NCCN classification system still outperforms other methods in the prediction of the probability of disease relapse.

Apoptotic dysregulation mediates stem cell competition and tissue regeneration

Since adult stem cells are responsible for replenishing tissues throughout life, it is vital to understand how failure to undergo apoptosis can dictate stem cell behavior both intrinsically and non-autonomously. Here, we report that depletion of pro-apoptotic Bax protein bestows hair follicle stem cells with the capacity to eliminate viable neighboring cells by sequestration of TNFα in their membrane. This in turn induces apoptosis in "loser" cells in a contact-dependent manner. Examining the underlying mechanism, we find that Bax loss-of-function competitive phenotype is mediated by the intrinsic activation of NFκB. Notably, winner stem cells differentially respond to TNFα, owing to their elevated expression of TNFR2. Finally, we report that in vivo depletion of Bax results in an increased stem cell pool, accelerating wound-repair and de novo hair follicle regeneration. Collectively, we establish a mechanism of mammalian cell competition, which can have broad therapeutic implications for tissue regeneration and tumorigenesis.

A Comprehensive Review of Natural Products as Therapeutic or Chemopreventive Agents against Head and Neck Squamous Cell Carcinoma Cells Using Preclinical Models

Head and neck squamous cell carcinoma (HNSCC) is a type of cancer that arises from the epithelium lining of the oral cavity, hypopharynx, oropharynx, and larynx. Despite the advancement of current treatments, including surgery, chemotherapy, and radiotherapy, the overall survival rate of patients afflicted with HNSCC remains poor. The reasons for these poor outcomes are due to late diagnoses and patient-acquired resistance to treatment. Natural products have been extensively explored as a safer and more acceptable alternative therapy to the current treatments, with numerous studies displaying their potential against HNSCC. This review highlights preclinical studies in the past 5 years involving natural products against HNSCC and explores the signaling pathways altered by these products. This review also addresses challenges and future directions of natural products as chemotherapeutic and chemoprevention agents against HNSCC.

Immunohistochemical expression of COX-2, Ki-67, Bcl-2, Bax, VEGF and CD105 according to histological grading in oral squamous cell carcinoma

INTRODUCTION

Oral squamous cell carcinoma (OSCC) is the most prevalent head and neck cancer. Few studies have analyzed the expression of proteins related to inflammation (COX-2) and tumor progression according to the histological grade of OSCC.

OBJECTIVE

Analyze the immunohistochemical expression of COX-2, Ki-67 (cell proliferation), Bcl-2/Bax (apoptosis), VEGF, and CD105 (angiogenesis) according to histological grades of OSCC.

MATERIAL AND METHODS

The immunohistochemical expression of COX-2, Ki-67, Bcl-2, Bax, VEGF, and CD105 of 58 cases of OSCC was analyzed. 13 cases of oral mucosa (OM) were analyzed as controls.

RESULTS

COX-2, VEGF, CD105, and Ki-67 were higher in OSCC than in OM, particularly in poorly differentiated OSCC (p<0.05). Bax expression was lower in poorly differentiated OSCC (p<0.001). The Bcl-2/Bax ratio was higher in OSCC compared to MO (p<0.05).

CONCLUSION

There are immunohistochemical differences according to histological grades of OSCC, which could influence clinical behavior.

Role of Toothbrushes as Gene Expression Profiling Tool for Oral Cancer Screening in Tobacco and Alcohol Users

AIM

The use of toothbrushes was investigated as a potential RNA source and gene expression profiling tool for oral cancer screening in tobacco and alcohol users.

METHODOLOGY

A total of 20 subjects were selected on the basis of inclusion and exclusion criteria. They were divided into two groups: group I-healthy controls (n = 6); group II-individuals who consume tobacco and alcohol (n = 14). After the volunteers brushed their teeth using a soft-bristle toothbrush with ~0.5 gm of toothpaste, the toothbrushes were collected, and the gene expression of BAX, BCL2, CDK4, CKDN2A, GNB3, and TCF7L2 was assessed.

RESULTS

The gene expression of BAX decreased significantly in alcoholics and smokers (0.13867 ± 0.12014), while the gene expression of BCL2 increased in alcoholics and smokers (1.91001 ± 0.90425) in comparison with healthy controls (p = 0.0054 and p = 0.0055). Although there was increased expression of CDK4, CKDN2A, and TCF7L2 and decreased expression of GNB3 in smokers and alcoholics, the results were not significant.

CONCLUSIONS

A toothbrush is a good source of RNA, and gene expression analysis can be performed using the genetic material retrieved from toothbrushes, which can aid in the early diagnosis of oral squamous cell carcinoma among tobacco and alcohol users. Further studies with a larger sample size and different durations of toothbrush use should be conducted to explore the role of toothbrushes as a noninvasive tool for disease diagnosis.

Proliferation and Apoptosis Pathways and Factors in Oral Squamous Cell Carcinoma

Oral cancer is the most common form of head and neck squamous cell carcinoma (HNSCC) and most frequently presents as oral squamous cell carcinoma (OSCC), which is associated with an alarmingly high mortality rate. Internationally, a plethora of research to further our understanding of the molecular pathways related to oral cancer is performed. This research is of value for early diagnosis, prognosis, and the investigation of new drugs that can ameliorate the harmful effects of oral cancer and provide optimal patient outcomes with minimal long-term complications. Two pathways on which the progression of OSCC depends on are those of proliferation and apoptosis, which overlap at many junctions. Herein, we aim to review these pathways and factors related to OSCC progression. Publicly available search engines, PubMed and Google Scholar, were used with the following keywords to identify relevant literature: oral cancer, proliferation, proliferation factors, genes, mutations, and tumor suppressor. We anticipate that the use of information provided through this review will further progress translational cancer research work in the field of oral cancer.

Intrinsic and extrinsic pathways of apoptosis: Role in cancer development and prognosis

Apoptosis, also named programmed cell death, is a fundament process required for morphogenetic homeostasis during early development and in pathophysiological conditions. It is come into existence in 1972 by work of Kerr, Wyllie and Currie and later on investigated during the research on development of the C. elegans. Trigger by several stimuli, apoptosis is necessary during the embryonic development and aging as homeostatic mechanism to control the cell population and also play a key role as defense mechanism against the immune responses and elimination of damaged cells. Cancer, a genetic disease, is a growing burden on the health and economy of both developing and developed countries. Every year there is tremendously increasing in the number of new cancer cases and mortality rate. Although, there is a significant improvement have been made in biotechnological and bioinformatic fields however, the therapeutic advantages and cancer etiology is still under explored. Several studies determined the deregulation of different apoptotic components during the cancer development and progression. Apoptosis relies on activation of distinct signaling pathways that are often deregulated in cancer. Thus, exploring the single or more than one apoptotic component underlying their expression in carcinogenesis could help to track the disease progression. Current book chapter will provide the several evidences supporting the use of different apoptotic components as prognosis and prediction markers in various human cancer types.

Apoptosis and genes involved in oral cancer - a comprehensive review

Oral cancers needs relentless research due to high mortality and morbidity associated with it. Despite of the comparable ease in accessibility to these sites, more than 2/3^rd cases are diagnosed in advanced stages. Molecular/genetic studies augment clinical assessment, classification and prediction of malignant potential of oral lesions, thereby reducing its incidence and increasing the scope for early diagnosis and treatment of oral cancers. Herein we aim to review the role of apoptosis and genes associated with it in oral cancer development in order to aid in early diagnosis, prediction of malignant potential and evaluation of possible treatment targets in oral cancer. An internet-based search was done with key words apoptosis, genes, mutations, targets and analysis to extract 72 articles after considering inclusion and exclusion criteria. The knowledge of genetics and genomics of oral cancer is of utmost need in order to stop the rising prevalence of oral cancer. Translational approach and interventions at the early stage of oral cancer, targeted destruction of cancerous cells by silencing or promoting involved genes should be the ideal intervention.

Preventive effect of D-carvone during DMBA induced mouse skin tumorigenesis by modulating xenobiotic metabolism and induction of apoptotic events

The structural integrity and excellent immune system of the skin makes it a protective covering, inspite of its exposure to hazardous compounds. In the present study, the chemopreventive efficacy of D-carvone was studied in 7, 12-dimethylbenz[a]anthracene (DMBA) induced skin carcinogenesis. DMBA (25 μg in 0.1 m L^-1acetone) was used to induce skin cancer in Swiss albino mice. Animals were randomly divided into six groups of six animals in each. Different concentrations of D-carvone (10, 20, 30 mg/kg body weight) were used to assess its anticancer effect. Tumor incidence, tumor volume, tumor burden, histological examination and levels of phase I and phase II detoxification agents were analyzed in experimental animals. Further, expression of p53 and various apoptotic proteins including- Bcl-2, Bax was analyzed using immunohistochemistry and enzymatic expression of apoptotic proteins caspase-3 and caspase-9 was carried out by using ELISA. We observed 100% tumor incidence in DMBA-painted animals and our results showed that D-carvone at 20 mg dose significantly prevents skin carcinogenesis. Our results also showed decreased levels of phase I enzymes (Cyt P450 and-Cyt b5) with increased levels of phase II enzymes (GR, GST and GSH) and increased expression of Bax, caspase-3 and caspase-9 with decreased expression of mutated p53 and Bcl-2 in animals treated with DMBA and D-carvone at 20 mg dose. The results of the present study suggest that D-carvone can be used as a chemopreventive agent against skin cancer, as it induces apoptosis in cancer. However, further studies are warranted to check chemopreventive efficacy of D-carvone on cell proliferation, angiogenesis, and metastasis before going to human trial.

Bcl-2 and c-Myc expression in oral dysplasia and oral squamous cell carcinoma: An immunohistochemical study to assess tumor progression

Introduction

Oral cancer is a multistep process involving foul play of proto-oncogenes that induce cell proliferation, inactivation of tumor suppressor gene and cessation of programmed cell death. Among various proto-oncogenes, the nature and behavior of Bcl-2 and c-Myc in oral precancerous/cancerous lesions were obscured which require further assessment for better understanding of etiology, treatment and prognosis.

Aim

The aim of the study is to assess the expression of Bcl-2 and c-Myc in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC).

Materials and Methods

This retrospective study of 70 (oral dysplasia [30], OSCC [30] and normal gingiva [10]) is immunohistochemically assessed for Bcl-2 and c-Myc for distribution, intensity, percentage of positive cells, localization and immunoreactive scores using ImageJ software.

Results

Bcl-2 showed 60% and 37% positivity within dysplasia and OSCC, respectively (P = 0.03); c-Myc showed 87% and 90% positivity within dysplasia and OSCC, respectively. In OSCC, c-Myc showed moderate intensity (P = 0.04). Average percentage of positive cells expressing c-Myc and Bcl-2 increased proportionally within grades of dysplasia (P = 0.000 and P = 0.008, respectively), whereas in OSCC, only c-Myc showed significant expression (P = 0.021). Localization of c-Myc was seen in the nucleus among OSCC (P = 0.01). c-Myc and Bcl-2 showed moderate immunoreactivity in dysplasia (P = 0.005 and P = 0.013, respectively), whereas in OSCC, moderate immunoreactivity of c-Myc (P = 0.05) was observed.

Conclusion

Variable expression of c-Myc and Bcl-2 reveals that these proteins act in synergism in early phases of carcinogenesis, whereas in later stages, due to the diminished activity of Bcl-2, c-Myc interacts incoordination with other oncogenes contributing to tumor progression.

Caspase-3 expression in normal oral epithelium, oral submucous fibrosis and oral squamous cell carcinoma

Context:

The epithelium atrophy, as the oral submucous fibrosis (OSMF) progresses, is believed to be an after effect of stromal fibrosis, hyalinization, decrease in vascularity and cellularity and is considered as “ischemic atrophy.” Due to hypoxia, caspase-3 get activation and subsequent decrease in viable cell count can occur.

Aims and Objectives:

To determine caspase-3 expression in various grades of OSMF and oral squamous cell carcinoma (OSCC) to find out whether upregulation of apoptosis is responsible for the epithelial changes in OSMF.

Subjects and Methods:

The control tissue (15 samples from normal oral mucosa) and study group comprising 97 cases of OSMF of different grades and OSCC associated with OSMF were stained with caspase-3 antibody, and the percentage of positive cells was calculated using ImageJ software.

Statistical Analysis:

The results obtained were statistically analyzed using ANOVA and Tukey's honest significance difference test and Mann–Whitney U-test.

Results:

There was a nuclear expression of caspase-3 in basal and parabasal layers of normal epithelium. There was cytoplasmic expression of caspase-3 in OSMF without dysplasia, total absence of caspase-3 expression in dysplastic epithelium and in majority cases of OSCC. The caspase-3 percentage was increased in OSMF (0%–53%) when compared with OSCC (0%–8%). The statistical comparison of caspase-3 among normal, OSMF and OSCC patients revealed significant correlation (P < 0.00010). The comparison within different grades of OSMF and between dysplastic and nondysplastic epithelium OSMF also showed significance (P < 0.019).

Conclusions:

The decreased expression of caspase-3 in disease progression reflects its role in the malignant transformation.

Influence of BCL2-938C>A and BAX-248G>A promoter polymorphisms in the development of AML: case-control study from South India

B-cell lymphoma 2 (BCL2) and BCL2-associated X protein (BAX) proteins are anti-apoptotic and pro-apoptotic determinants of mitochondrial-mediated apoptosis, and their relative expression determines the cell fate. The promoter polymorphisms in these genes were shown to alter the protein function or expression and exert an impact on apoptosis regulation. Deregulation in the expression of any of these genes leads to disruption of cellular homeostasis and malignant transformation. The present study was aimed to determine the association of BCL2-938C>A and BAX-248G>A promoter polymorphisms with origin and progression of acute myeloid leukemia (AML). We also have performed combined genotype analysis to evaluate the cumulative effect of risk genotypes in the AML development. These polymorphisms were genotyped by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) in 221 AML patients and 305 age- and sex-matched healthy controls. Our study revealed that BCL2-938CA (p = 0.018) and BAX-248GG (0.043) genotypes were significantly associated with increased risk for AML occurrence. BAX-248A allele had shown decreased risk for AML. The combined analysis had shown that BCL2-938CA+AA-BAX-248GG group had a 1.63-fold (95 % CI: 1.08-2.45, p = 0.02) increased risk for AML. None of the clinical variables had shown any significant association with both polymorphisms. With respect to complete remission (CR) rate, BAX-248GG genotype (p = 0.002) and G allele (p = 0.009) had conferred significant risk for complete remission failure. Although the log rank test was not significant, survival analysis had shown a trend where BCL2-938CA genotype, and BAX-248GG had reduced median disease-free survival (DFS) of 9 and 10 months, respectively. In conclusion, BCL2-938C>A and BAX-248G>A gene polymorphisms might contribute to the origin of AML. Moreover, influence of BAX-248GG genotype on CR and DFS rate suggests that the BAX-248G>A polymorphism can serve as marker for poor prognosis in AML.

Combinatorial chemopreventive effect of butyric acid, nicotinamide and calcium glucarate against the 7,12-dimethylbenz(a)anthracene induced mouse skin tumorigenesis attained by enhancing the induction of intrinsic apoptotic events

We explored the basis of the combinatorial chemopreventive effect of butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG) on mouse skin exposed to 7,12-dimethylbenz(a)anthracene (DMBA). We studied the effects of topical application of DMBA in the presence or absence of BA, NA and CAG on the regulators of apoptosis. DMBA treatment suppressed Bax, Bax/Bcl-2 ratio, release of cyt c, Apaf1, caspase-9, -3 mediated apoptosis. Downregulation of p21 and upregulation of Bcl-2, mut p53 were also observed in only DMBA treated mice. Simultaneous application of BA, NA and CAG induced a mitochondria-mediated apoptosis, characterized by a rise in the Bax, Bax/Bcl-2 ratio, release of cyt c, upregulation of Apaf1 with down-stream activation of caspase-9, -3. Furthermore treatment with BA, NA and CAG demonstrated an upregulation of p21 and downregulation of Bcl-2, mut p53. But this effect was enhanced in the presence of all the three compounds together in combination. Chemoprevention by a combination of BA, NA and CAG by inducing the apoptosis, the natural cell death, suggest the importance of the potential combinational strategies capable of preventing skin tumor development.

Expression of Bcl-2 and MIB-1 Markers in Oral Squamous Cell Carcinoma (OSCC)- A Comparative Study

BACKGROUND

Neoplasia results from various genetic and epigenetic factors. Our study focused on the pathogenesis which involved an imbalance in various molecular mechanisms which regulated cell proliferation and apoptosis. The anti-apoptotic mechanism is regulated by Bcl-2 gene, while Ki-67 is expressed exclusively in nuclei of proliferating cells. This study was done to evaluate the basic pathologic process which underlay well and poorly differentiated oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Thirty cases of oscc were selected, out of which 11 were well differentiated, 9 were moderately differentiated and 10 were poorly differentiated. Three slides of 4μm thickness were prepared out of each sample, which were then subjected to Hematoxylin and eosin stain (H&E) staining and two types of immunohistochemical (IHC) staining. Immunohistochmical markers used were Ki-67 (proliferative marker using MIB-1 (Molecular Immunology Borstel 1) antibody) and Bcl-2 (anti-apoptotic marker). The number of MIB-1 and Bcl-2 positive cells was calculated from ten different high power fields, by counting the number of positive cells per 50 cells in each field, by making a grid pattern. The overall percentage value for each case was evaluated for MIB-1 and Bcl-2 positive cells. Karl-Pearson's co-relation coefficient was calculated between MIB-1 and Bcl-2 in each group. The aim of this study was to co-relate the expression of Ki-67, a proliferative marker, by using MIB-1 antibody and Bcl-2, an anti-apoptotic marker in various grades of oscc and also to determine whether there was any co-relation between these two markers in the 30 cases of oscc .

RESULTS

A statistically significant increase for MIB-1 and a statistically significant decrease for Bcl-2 was found in well to moderately to poorly differentiated Squamous cell carcinoma (SCC). A statistically significant co-relation was also found between MIB-1 and Bcl-2 in poorly differentiated oscc .

CONCLUSION

MIB-1 expression is predominant in well, moderate and poorly differentiated SCCs. Bcl-2 expression is predominant in well differentiated than in moderately and poorly differentiated oscc , which suggested that apoptosis probably played a major role in the early stages of carcinogenesis.

Induction of apoptosis in oral epithelial cells by Candida albicans

During infection, interactions between Candida albicans and oral epithelial cells result in oral epithelial cell death. This is clinically manifested by the development of oral mucosal ulcerations generally associated with discomfort. In vitro studies have shown that C. albicans induces early apoptotic alterations in oral epithelial cells; however, these studies have also shown that treatment of infected cells with caspase inhibitors does not prevent their death. The reasons for these contradictory results are unknown and it is still not clear if C. albicans stimulates oral epithelial signaling pathways that promote apoptotic cell death. Activation of specific death pathways in response to microbial organisms plays an essential role in modulating the pathogenesis of a variety of infectious diseases. The aim of this study was to (i) characterize C. albicans-induced apoptotic morphological alterations in oral epithelial cells, and (ii) investigate the activation of apoptotic signaling pathways and expression of apoptotic genes during infection. Candida albicans induced early apoptotic changes in over 50% of oral epithelial cells. However, only 15% of those showed mid-late apoptotic alterations. At the molecular level, C. albicans caused a loss of the mitochondrial transmembrane potential and translocation of mitochondrial cytochrome c. Caspase-3/9 activities increased only during the first hours of infection. Moreover, poly[ADP ribose] polymerase 1 was cleaved into apoptotic and necrotic-like fragments. Finally, five anti-apoptotic genes were significantly upregulated and two pro-apoptotic genes were downregulated during infection. Altogether, these findings indicate that epithelial apoptotic pathways are activated in response to C. albicans, but fail to progress and promote apoptotic cell death.

Proliferation and apoptosis markers in oral submucous fibrosis

BACKGROUND

Premalignant/potentially malignant-oral lesions and conditions such as oral submucous fibrosis are known to transform into oral cancer. The malignant transformation is often associated with changes at the genetic level that in turn is reflected by the altered expression of proteins related to cell cycle, proliferation, and apoptosis.

AIM

To evaluate the expression of p53, Ki67 (MIB), bcl2, and bax in oral submucous fibrosis and oral squamous cell carcinoma.

MATERIALS AND METHODS

To assess the immunohistochemical expression of p53, Ki67 (MIB), bcl2, and bax in 50 cases of oral submucous fibrosis (OSF) and ten each of normal and oral squamous cell carcinoma (OSCC).

RESULTS

The labeling indices (LI) of OSF and OSCC were comparable for p53 and Ki67.The p53 LI ranged from 7.9 to 71.9 in OSF and 65.2 to 85.9 in OSCC, and for Ki67 it ranged from 4.39 to 43.23, 18.35 to 42.33, respectively.

CONCLUSION

The p53, Ki67, and bax profiles of OSF and OSCC were altered compared to the normal and these markers could be used as surrogate markers of malignant transformation in OSF.

Loss of desmoglein 1 expression associated with worse prognosis in head and neck squamous cell carcinoma patients

AIMS

Mucosal squamous cell carcinomas are the most common head and neck malignancies. We hypothesised that over-expression of intracellular signalling proteins and decreased expression of desmoglein molecules would be associated with aggressive tumour behaviour in patients with head and neck squamous cell carcinoma.

METHODS

Seventy-eight cases of head and neck squamous cell carcinoma were immunohistochemically stained for desmoglein 1, desmoglein 2, desmoglein 3, p53, bcl-2, vimentin, cyclin D1, p16, p21, p27, E-cadherin, and E2F-1 in paraffin-embedded tissue blocks in a microarray.

RESULTS

The disease-specific survival was 56% at 5 years and 49% at 10 years. Expression of the desmoglein isotypes correlated positively with each other except for desmoglein 2 and desmoglein 3, which did not show a significant correlation. Desmoglein 1 and E-cadherin expression also correlated. On univariate analysis, only expression of desmoglein 1 correlated with patient outcome; lack of expression of desmoglein 1 was associated with a significantly worse disease-specific survival (p = 0.035). Hierarchical clustering analysis identified a subgroup of three patients with an immunophenotype distinct from the other tumours, characterised by co-expression of p16, p27, E2F-1 and bcl-2. Further statistical analysis of the prognostic significance of this small subgroup was not possible, but these three patients are alive and well.

CONCLUSIONS

Decreased expression of desmoglein 1 is associated with a worse prognosis in head and neck squamous cell carcinoma patients. Examination of an extended panel of immunomarkers revealed a rare subtype of squamous cell carcinoma characterised by the expression of multiple proliferation-associated markers and the anti-apoptotic protein, bcl-2; determination of the prognostic significance of this subgroup will require study of a larger case series.

Activation of MAP kinase signaling through ERK5 but not ERK1 expression is associated with lymph node metastases in oral squamous cell carcinoma (OSCC)

In an attempt to further elucidate the pathomechanisms in oral squamous cell carcinoma (OSCC), gene expression profiling was performed using a whole-transcriptome chip that contains 35,035 gene-specific 70 mere oligonucleotides (Human OligoSet 4.0; Operon, Cologne, Germany) to a set of 35 primary OSCCs. Altogether, 7390 genes were found differentially expressed between OSCC tumor samples and oral mucosa. To characterize the major biologic processes in this tumor collection, MAPPFinder, a component of GenMAPP version 2.1, was applied to this data set to generate a statistically ranked list of molecular signaling pathways. Among others, cancer-related pathways, such as mitogen-activated protein (MAP) kinase signaling (z score = 4.6, P < .001), transforming growth factor-beta signaling (z score = 3.0, P = .015), and signaling pathways involved in apoptosis (z score = 2.1, P = .037), were found deregulated in the OSCC collection analyzed. Focusing on the MAP kinase signaling pathway, subsequent tissue microarray analyses by immunohistochemistry revealed an increase in protein expression of MAP kinase-related proteins ERK1 in 22.8% (48 of 209) and ERK5 in 27.4% (76 of 277), respectively. An association of high ERK5 but not of high ERK1 expression with advanced tumor stage and the presence of lymph node metastases was found (P = .008 and P = .016, respectively). Our analysis demonstrates the reliability of the combined approach of gene expression profiling, signaling pathway analyses, and tissue microarray analysis to detect novel distinct molecular aberrations in OSCC.

Diabetes enhances cell proliferation but not Bax/Bcl-2-mediated apoptosis during oral oncogenesis

Markers of cell proliferation (Ki-67 antigen) and apoptosis (Bax, Bcl-2) were studied in an experimental model of chemically induced carcinogenesis in normal and diabetic (type I) Sprague-Dawley rats. Thirteen diabetic and 12 normal rats developed cancer after 4-nitroquinoline-N-oxide treatment, while 6 diabetic and 6 normal animals were used as controls. The biopsies were classified pathologically (from oral mucosal dysplasia to moderately differentiated squamous cell carcinoma) and studied immunohistochemically using monoclonal antibodies against Bax, Bcl-2 and Ki-67 proteins. The Bcl-2/Bax ratio was almost stable during the oncogenesis process in the diabetic rats, whereas the normal rats showed an increased Bcl-2/Bax ratio during the stage of moderately differentiated carcinoma. In contrast, Ki-67 expression was higher in diabetic rats than in normal ones in almost all stages of oral oncogenesis, and it reached significantly increased levels in the stages of normal control tissue, dysplasia and moderately differentiated squamous cell carcinoma. These data suggest that diabetes results in increased cell proliferation during oral oncogenesis, but this is accomplished without affecting the Bax/Bcl-2-mediated apoptotic pathways.

The hamster model of sequential oral oncogenesis

Oral squamous cell carcinoma (OSCC) is a common cancer characterised by low survival rate and poor prognosis. The multistep process of oral carcinogenesis is affected by multiple genetic events such as alterations of oncogenes and tumour suppressor genes. The use of appropriate experimental animal models that accurately represent the cellular and molecular changes which are associated with the initiation and progression of human oral cancer is of crucial importance. The Syrian golden hamster cheek pouch oral carcinogenesis model is the best known animal system that closely correlates events involved in the development of premalignant and malignant human oral cancers. Therefore, we established an experimental system of chemically induced oral carcinogenesis in hamsters, in order to study different stages of tumour formation: normal mucosa, hyperkeratosis, hyperplasia, dysplasia, early invasion, well differentiated OSCC and moderately differentiated OSCC. We investigated the expression of oncogenes EGFR, erbB2, erbB3, FGFR-2, FGFR-3, c-myc, N-ras, ets-1, H-ras, c-fos and c-jun, apoptosis markers Bax and Bcl-2, tumour suppressor genes p53 and p16, and cell proliferation marker Ki-67 in the sequential stages of hamster oral oncogenesis. Here, we describe the findings of the experimental model in regard to the involvement of signal transduction pathways in every stage of cancer development. Increased apoptosis and cell proliferation were observed in early stages of oral oncogenesis. Furthermore, the increased expression of transmembrane receptors (EGFR, erbB2, FGFR-2 and FGFR-3) as well as the increased expression of nuclear transcriptional factors in early stages of oral cancer indicates that these molecules may be used as early prognostic factors for the progression of OSCC. Since the expression of both H-ras and N-ras do not seem to affect signal transduction during oral oncogenesis, it can be assumed that a different signalling pathway, such as the PI3K and/or PLCgamma pathway, may be implicated in the pathogenesis of OSCC.

TUNEL - an efficient prognosis predictor of salivary malignancies

Biological markers are necessary for predicting prognosis of salivary malignancies and better understanding the pathogenesis of salivary cancer. We analysed terminal deoxynucleotidyl transferase (TdT)-mediated biotinylated deoxyuridine-triphosphate (dUTP)-biotin nick-end labelling (TUNEL), p53 and Ki67 expression in 66 patients with malignant salivary tumours by immonohistochemistry, and correlated the data with survival, disease-free survival, tumour grade, stage, and local and distant metastasis. TUNEL efficiently predicted poor prognosis in salivary malignancies. The 5-year (5Y) survival probability dropped significantly with the level of TUNEL staining (from 83% in negatively stained tumours to 57 and 24% in TUNEL positively stained levels 1 and 2, respectively), (P=0.042). Extensive Ki67 staining (in addition to TUNEL) reduced the 5Y-survival rate even further and addition of positively stained p53 dropped the 5Y-survival rate to 0. The correlation rates between TUNEL and Ki67 was 58% (P=0.0001), and between TUNEL and p53 it was 50% (P=0.035). Concurrently, TUNEL correlated with metastasis, extracapsular spread, grade and stage. The correlation between TUNEL, p53 and Ki67 staining and survival probabilities, and the pathological grade, stage and metastasis spread of salivary malignancies makes this a highly effective tool in patient follow-up and prognosis.

Establishment and characterization of a tumorigenic cell line from areca quid and tobacco smoke-associated buccal carcinoma

A cell line, TW2.6, has been established from the surgically resected specimen of an untreated primary squamous cell carcinoma of the buccal mucosa from a 48-year-old man who was an areca quid chewer and tobacco smoker. TW2.6 cells exhibited morphological features of keratinocytes and replicated rapidly in culture with a doubling time of 24h. The karyotype showed human chromosomes with high hyperdiploidy and complex rearrangements. Western blotting showed pronounced expression of p53 and moderate expression of p21(CIP1). The baseline expressions of p27(KIP1) and p16(INK4a) were barely detectable. Low levels of Bax and Fas were found in TW2.6 cells but Bcl-2 expression was more readily observed. Mutational analysis of p53 gene revealed an A-->G transition at the second base of codon 220, resulting in amino acid substitution from tyrosine to cysteine in the protein. Functional analysis showed that TW2.6 was unable to activate the p53-specific PUMA promoter. Lipofectamine 2000 and calcium phosphate precipitation technique offer good transfection efficiencies for TW2.6 cells and may be used in future transfection experiments. A xenograft-SCID mouse tumor model was established for TW2.6. Histological examination demonstrated that the engrafted tumors maintained the morphological features of a squamous cell carcinoma. It is thought that the establishment of tumorigenic TW2.6 cell line provides a valuable model for AQ and tobacco smoke-associated buccal carcinoma.

Cell proliferation and apoptosis culminate in early stages of oral oncogenesis

Markers of cell proliferation (Ki-67 antigen) and apoptosis (Bax, Bcl-2) were studied in an experimental system of induced oral carcinogenesis in Syrian golden hamsters. Thirty-seven animals were divided into one control group and three experimental groups, which were treated with a carcinogen and sacrificed at 10, 14 and 19 weeks after treatment. The histological status of the lesions in the three experimental groups corresponded well with tumour advancement (from oral mucosal dysplasia to moderately differentiated squamous cell carcinoma). Tumour sections were studied using monoclonal antibodies against Bax, Bcl-2 and Ki-67 proteins. Pro-apoptotic Bax expression maintained high levels during all stages of oral carcinogenesis. Anti-apoptotic Bcl-2 expression decreased significantly in dysplastic and early invasion lesions and consequently increased almost to normal tissue level in consequent stages. Finally, Ki-67 expression increased sharply in initial stages of oral carcinogenesis, but significantly decreased in later stages.

Expression of Bcl-2 but not Bax has a prognostic significance in tongue carcinoma

BACKGROUND

Among the molecular mechanisms involved in carcinogenesis, defects in the regulation of programmed cell death (apoptosis) make important contributions to the pathogenesis and progression of cancer. Apoptosis regulatory genes include the antiapoptotic bcl-2 gene and the proapoptotic bax gene. The aim of this study was to determine the spectrum of Bax and Bcl-2 expression, and to correlate these findings with clinicopathologic variables and prognosis.

METHODS

In this study we have evaluated the immunohistochemical expression of Bcl-2 and Bax proteins in a series of 35 squamous cell carcinomas of the tongue.

RESULTS

Immunoreactivity for Bax was detected in 37.1% and for Bcl-2 in 8.6% of cells, and for both proteins the staining was cytoplasmic and granular. Bcl-2 and Bax expression was mainly seen in peripheral cells of epithelial tumor islands with decreasing immunoreactivity toward the center of the neoplastic nests. Bax immunoexpression was significantly correlated with histologic grading (P=0.05), but not with the remaining clinicopathologic variables. Bcl-2 immunoreactivity was significantly correlated with N-stage (P=0.01) and survival. Patients with Bcl-2-negative tumors [mean survival: 73.97 months; 95% confidence interval (CI): 59-88] vs. Bcl-2-positive ones (mean survival: 17.67 months; 95% CI: 6-29) had a longer survival (P=0.01; odds ratio=6.9).

CONCLUSIONS

Bcl-2 is associated with aggressive disease, neck lymph node metastasis, and poor prognosis. Whereas Bax is related with histologic grade.

Loss of BCL-2 in the progression of oral cancer is not attributable to mutations

BACKGROUND

BCL-2 and BAX are important in the regulation of apoptosis. There have been reports of loss of BCL-2 in basal cells of oral epithelial dysplasia (OED) and in oral squamous cell carcinoma (OSCC), and suppression of BAX in poorly differentiated OSCC.

AIM

To investigate whether loss of BCL-2 in OED and OSCC, and of BAX in poorly differentiated OSCC could be attributed to BCL-2 and BAX mutations.

METHODS

Immunohistochemistry and in situ hybridisation were used to confirm BCL-2 and BAX expression. DNA was extracted from archival samples of OED (n = 22) and OSCC (n = 28). The connective tissue part from each section was collected separately and used as the normal reference.

RESULTS

No mutations were detected in BCL-2 or BAX that could explain their aberrant expression at the mRNA and protein levels in OED and OSCC. The reported A/G polymorphism at codon 7 of BCL-2 was detected in 18 of 50 samples and a novel C/T polymorphism at codon 100 was detected in three of 50 samples.

CONCLUSIONS

No mutations were found that could explain loss of BCL-2 in oral dysplasia and carcinoma. An unreported C/T polymorphism in BCL-2 was detected. Downregulation of BCL-2 in OED and OSCC may be the result of transcriptional regulation.

Apoptosis in normal and diseased oral tissues

Apoptotic cell death plays an important role in maintenance of the normal physiological state and in the pathogenesis of diseases in the body. Over the last three decades the molecular mechanisms of apoptosis have been unravelled leading to development of novel therapeutic approaches. This paper aims to present current knowledge of the role of apoptosis in normal oral tissues and in the development of oral diseases.

Two-phase appearance of oral epithelial dysplasia resulting from focal proliferation of parabasal cells and apoptosis of prickle cells

BACKGROUND

One of the histologic characteristics of epithelial dysplasias of the oral mucosa is droplet-shaped rete processes resulting from a solid proliferation of basaloid cells. These basaloid cells are suddenly changed into an overlay of parakeratotic cells. However, it is unknown how this characteristic two-phase appearance is generated.

METHODS

Formalin-fixed paraffin sections of the oral mucosal specimens with normal, hyperplastic, dysplastic epithelia and squamous cell carcinomas were examined for apoptosis by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) method and for lymphoid cells by immunohistochemistry.

RESULTS

Apoptotic cells were only located in the keratinized layer of normal/hyperplastic epithelia. However, in epithelial dysplasias, apoptotic cells were scattered in the middle or even in the lower parts of the epithelial layer with frequent vacuolation changes of epithelial cells. Within the epithelial layer of dysplasias, there were increased number of lymphocytes, which were immunopositive for CD45RO, CD8, and CD57- and CD68-immunopositive (+), S-100 protein-positive and major histocompatibility complex (MHC) class II-positive monocytic lineages. They increased in number with the severity of dysplastic degrees, and they were often located in the vicinity of apoptotic epithelial cells, but decreased in carcinomas in situ and invasive carcinomas, which contained fewer numbers of apoptotic figures.

CONCLUSION

The findings indicate that intraepithelial infiltrations of both cytotoxic T cells and natural killer cells are closely related to the apoptotic phenomena of prickle cells, which may result in the characteristic 'two-phase appearance' of epithelial dysplasia.

BCL2 and JUNB abnormalities in primary cutaneous lymphomas

BACKGROUND

BCL2 is upregulated in nodal and extranodal B-cell non-Hodgkin's lymphomas, with a consequent antiapoptotic effect. However, loss of BCL2 has also been noted in some malignancies, suggesting a different molecular pathogenesis.

OBJECTIVES

To investigate genomic and protein expression status of BCL2 and to compare the results with that of JUNB in primary cutaneous lymphomas (PCLs).

METHODS

We analysed gene copy number of BCL2 and JUNB in 88 DNA samples from 80 patients with PCL consisting of Sézary syndrome/mycosis fungoides (SS/MF), primary cutaneous B-cell lymphoma (PCBCL) and primary cutaneous CD30+ anaplastic large cell lymphoma (C-ALCL) by the use of real-time polymerase chain reaction (PCR) and immunohistochemistry (IHC). Real-time PCR and IHC findings were subsequently compared with the results of additional fluorescent in situ hybridization (FISH) analysis of 23 cases of SS and Affymetrix cDNA expression microarray study of two primary cutaneous T-cell lymphoma (CTCL) cell lines.

RESULTS

Real-time PCR analysis showed loss of BCL2 gene copy number in 22 of 80 PCL cases (28%), including 17 of 42 SS/MF, three of 13 C-ALCL and two of 33 PCBCL samples, and gain of BCL2 in four PCBCL samples. Gain of JUNB was identified in 18 of 71 PCL cases (25%), including nine of 35 SS/MF, seven of 13 C-ALCL and two of 31 PCBCL samples. IHC analysis revealed absent nuclear expression of BCL2 protein in 47 of 73 PCL cases, comprising 28 of 36 SS/MF, eight of eight C-ALCL and 11 of 29 PCBCL cases. In contrast, BCL2 protein expression was detected in 26 of 73 PCL cases, consisting of 18 of 29 PCBCL and eight of 36 SS/MF cases. JUNB protein expression was present in tumour cells from 30 of 33 of SS/MF and eight of eight C-ALCL, and was absent in tumour cells from 18 of 27 PCBCL cases. A comparison between BCL2 and JUNB revealed loss of BCL2 and gain of JUNB in five of 35 SS/MF samples, and expression of JUNB protein and absent BCL2 expression in 25 SS/MF and eight of eight C-ALCL cases. In contrast, expression of BCL2 and absent JUNB expression were detected in 67% of PCBCL cases. Additional FISH analysis revealed deletion of BCL2 in 19 of 23 SS cases (83%), including eight cases with BCL2 loss shown by real-time PCR. Furthermore, Affymetrix expression microarray demonstrated decreased expression of proapoptotic and antiapoptotic genes involved in BCL2 signalling pathways such as BOK, BIM, HRK, RASA1 and STAT2 in two CTCL cell lines with BCL2 loss and absent BCL2 expression. Increased expression of JUNB was also identified in the MF cell line.

CONCLUSIONS

These findings provide a comprehensive assessment of BCL2 and JUNB status in PCL, and suggest that there is a selection pressure in a subset of CTCL cases for tumour cells showing BCL2 loss and upregulation of JUNB primarily through chromosomal deletion and amplification, respectively.

Detection of bcl-2 and bax expression and bcl-2/JH fusion gene in intrahepatic cholangiocarcinoma

AIM: To investigate the relationship between bcl-2 gene and its related protein bax and intrahepatic cholangiocellular carcinoma (CCC).

METHODS: Semi-nested in situ PCR (SNISPCR) and imm- unohistochemistry were performed to detect bcl-2/JH fusion gene and bcl-2, bax protein expression in 29 cases of CCC.

RESULTS: No bcl-2/JH fusion gene was found in all cases of CCC, 72.4% of 29 cases expressed bcl-2 protein. Bcl-2 protein expression was related to histopathological grades (P < 0.05). There was no corresponding relationship between bcl-2/JH fusion gene formation and bcl-2 protein expression in CCC (P < 0.05). Bax was expressed in 10.3% of 29 cases. The ratio of bcl-2 to bax in normal liver tissues (3.5 to 1) was different from that in tumor tissues (7.0 to 1).

CONCLUSION: It is suggested that bcl-2/JH fusion gene formation is not a frequent event and may not play an important role in the pathogenesis of CCC. However, aberrant ratio of bcl-2 to bax protein expression may be involved in the course of tumorigenesis of CCC. Abnormal bcl-2 protein expression may not be solely resulted from bcl-2/JH fusion gene.

99mTc-HYNIC Annexin-V imaging of primary head and neck carcinoma

In this study, the potential of 99mTc-HYNIC Annexin-V scintigraphy to visualize primary head and neck carcinoma was assessed and compared with computed tomography (CT) findings and histology. Eighteen patients suspected of having primary head and neck carcinoma underwent a spiral CT scan and 99mTc-HYNIC Annexin-V scintigraphy within 1 week of each other, followed by resection of the suspected lesion. Results obtained by CT and scintigraphy were compared vs. histopathology. The diagnosis was primary head and neck carcinoma in 18 patients, accompanied by lymph node involvement in seven patients. 99mTc-HYNIC Annexin-V uptake was identified in five patients on planar images and in 17 patients on tomographic images (single-photon emission computed tomography, SPECT), corresponding to the pathological regions identified by CT. In the remaining patient, CT and 99mTc-HYNIC Annexin-V scintigraphy were false negative. In 11 patients, SPECT and CT scan were concordant, identifying all primary lesions and two sites of lymph node involvement. In the six remaining patients, CT and SPECT accurately identified the primary lesion, but were discordant with regard to the existence of lymph node involvement. In five of six patients, SPECT failed to identify lymph node involvement, whereas CT scan did not. In the remaining patient, CT scan was false positive for lymph node involvement, whereas SPECT was not. In this series, 99mTc-HYNIC Annexin-V allowed for the visualization of all primary head and neck tumours identified by CT scan, but failed to identify most of the sites of lymph node involvement.

Detection of apoptotic cells in whole saliva of patients with oral premalignant and malignant lesions: A preliminary study

OBJECTIVE

The purpose of this study was to identify and measure apoptotic cells in whole saliva of patients with oral premalignant and malignant lesions and explore its utility as a prognostic indicator.

STUDY DESIGN

A fluorescent TUNEL technique (APO-BrdU TUNEL) modified by our lab was applied to unstimulated whole saliva from 8 healthy volunteers, 16 patients with oral leukoplakia and/or lichen planus, 10 untreated and 5 treated cases with oral malignant lesion.

RESULTS

The apoptotic cells in whole saliva were detected in 4 groups of study subjects. The apoptotic cells demonstrated morphology similar to normal exfoliated epithelial cells of oral mucosa. The fraction of apoptotic cell in treated malignant patients (18.18+/-12.65) was significantly higher than that in healthy volunteers (6.99+/-6.52), premalignant patients (4.43+/-5.52), and untreated malignant patients (3.40+/-5.14) (P<.05).

CONCLUSION

Detection of apoptotic epithelial cells in whole saliva appears to have some clinical potential in monitoring reaction to chemoradiotherapy and may reveal some insight into the mechanism of oral carcinogenesis.

Crucial Effects of Fibroblasts and Keratinocyte Growth Factor on Morphogenesis of Reconstituted Human Oral Epithelium

The connective tissue is known to have a general supportive effect for the development of the overlying epithelium; however, the more specific effects of fibroblasts and the involvement of their product, keratinocyte growth factor, on oral epithelial morphogenesis have not yet been addressed. Therefore, the purpose of this study was to investigate the effects of fibroblasts and keratinocyte growth factor on human oral epithelial morphogenesis in vitro. Reconstituted human oral epithelium was generated from primary human oral keratinocytes and fibroblasts by use of an organotypic cell culture model in a defined medium. Addition of fibroblasts to the collagen biomatrix increased total epithelial thickness from 28.0+/-5.0 microm to 66.1+/-8.6 microm (p=0.028), and basal cell proliferation from 3.6+/-0.7% to 16.6+/-1.1% (p=0.025). Presence of fibroblasts profoundly influenced the pattern of epithelial differentiation, and induced a switch in the pattern of cell death, from a predominance of spontaneous cell death in the basal cell layer (from 4.7+/-0.6% to 1.8+/-0.3%, p=0.029) to a more prevalent cell death due to terminal differentiation in the suprabasal cell layer (from 4.0+/- 0.1% to 5.4+/-0.1%, p=0.034). Keratinocyte growth factor promoted epithelial growth, but did not significantly enhance epithelial differentiation, demonstrating that fibroblasts possess additional mechanisms to keratinocyte growth factor synthesis that can modulate differentiation of reconstituted human oral epithelium.

Prognostic relevance of molecular markers of oral cancer--a review

The aim of the present article was to review the current knowledge on the prognostic value of tumour marker in the treatment of oral squamous cell carcinoma (OSCC). The literature of the past 5 years (1997-August 2002) was screened. One hundred and sixty-nine articles were included in this review, twenty-nine molecular markers of relevance were identified. Tumour markers were allocated to four groups according to their function: (i) Enhancement of Tumour Growth: Cell cycle acceleration and proliferation, (ii) Tumour Suppression and Anti-Tumour Defence: Immune response and apoptosis, (iii) Angiogenesis, (iv) Tumour Invasion and Metastatic Potential: Adhesion molecules and matrix degradation. Data showed that the prognostic relevance of most tumour markers is still not quite clear. Only 12 of 23 reports on the prognostic relevance of markers for cell cycle acceleration and proliferation indicated a significant association with prognosis while 20 of 29 studies on markers for tumour suppression and anti-tumour response showed prognostic relevance. Markers of angiogenesis exhibited only minor importance for the prognosis and treatment of OSCC. Results on markers of tumour invasion and metastatic potential appeared to be too premature for a statement regarding their prognostic value. In general, the location of markers within the tumour and not their quantitative assessment as such is emphasized. Particularly, the analysis of the invasive front of the tumour with regard to the occurrence of molecular markers is supposed to be of great importance for prognostication.

Cyclic guanosine monophosphate phosphodiesterase activity in human gingival carcinoma

BACKGROUND

Cyclic guanosine monophosphate (cGMP) is an essential second messenger metabolized by phosphodiesterases (PDEs).

OBJECTIVES

We looked for a possible correlation of PDE activities in human oral squamous cell carcinoma (OSCC) with and without lymph node metastases.

MATERIALS AND METHODS

The analysis of phosphodiesterase activity and the cGMP assay were done by reverse-phase HPLC on samples of fresh or frozen gingival tissues. Analysis of cGMP was confirmed with the enzyme-linked immunoabsorption assay.

RESULTS AND CONCLUSIONS

cGMP PDE activity was 34.92 +/- 7.17 SD, 12.89 +/- 4.43 SD, and 35.88 +/- 8.76 SD (nmols/mg of protein), respectively, in controls, samples without lymph node involvement (N-), and specimens with lymph node metastases (N+). cGMP values were 1.97 +/- 0.63 SD, 3.30 +/- 1.47 SD, and 3.49 +/- 1.47 SD (nmols/mg of protein). Our data support the hypothesis of a role for cGMP and PDE in the progression of OSCC.

Cell death regulation in oral squamous cell carcinoma: methodological considerations and clinical significance

In the last three decades, more work has been done on apoptosis and its role in the pathogenesis of many diseases including cancer. In almost all instances of cancer, dysregulation of cell death (apoptosis) and cell proliferation have been found to play a major role in tumourigenesis. A lot of progress has been made on understanding the molecular basis of apoptosis and its regulatory mechanisms. This review focuses on current knowledge on the regulation of apoptosis in oral squamous cell carcinoma, current methodologies and methodological consideration in estimation of cell death in tissue sections and the clinical significance of apoptosis related molecules in progression of oral squamous cell carcinoma.

Squamous cell carcinoma of the tongue: the prevalence and prognostic roles of p53, Bcl-2, c-erbB-2 and apoptotic rate as related to clinical and pathological characteristics in a retrospective study

In the current study, we examined the clinical characteristics and survival probability rates of 116 patients treated for squamous cell carcinoma (SCC) of the tongue. In 55 randomly selected patients these data were correlated with the immunohistological analysis of the tumor and apoptosis-related markers, p53, Bcl-2, c-erbB-2 (Her-2/neu), and to the apoptosis rate assessment by the terminal dUTP nick-end-labeling (TUNEL) method. The overall 5-year survival probability was 55%, which might be the result of the low incidence of smoking and/or alcohol consumption among the patients (21%), the early diagnosis (65% at Stages I-II) and the low histological grades (91% good-moderate). Radiotherapeutic or surgical treatment of the neck did not alter the survival probability achieved by local surgery for Stage I patients, but significantly improved survival for Stage II patients. Independent tumor-related variables which significantly worsened the probability of survival were found. Concomitant non-oral cancer was found to be a poor variable for prognosis prediction. Positive staining of p53, TUNEL (apoptosis rate), c-erbB-2 and Bcl-2 was found in 60, 48, 18 and 15% of the lesions, respectively (P<0.0001). The possible biological significance of these markers in tongue SCC is discussed in relation to the current literature, and an independent role for TUNEL and p53 is suggested.

Clinicopathologic significance of bcl-2 expression in the surgical treatment of oral tongue carcinoma

AIM

There is still controversy on the incidence of positive expression of bcl-2 and its prognostic significance for oral tongue carcinoma patients who are treated by surgery. The present study aims at resolving the controversy on the clinicopathologic significance of bcl-2 in a well selected group of patients who satisfy the recruitment criteria: (1) oral tongue carcinoma, (2) squamous cell carcinoma, (3) primary surgical treatment.

METHOD

Bcl-2 expression was studied by immunohistochemistry on glossectomy specimens of 73 patients. The expression of bcl-2 was correlated with clinicopathologic data.

RESULTS

Of the 73 tumours, 11% had positive expression of bcl-2. Bcl-2 expression was not significantly correlated with tumour grade, stage, nodal metastasis and survival.

CONCLUSION

Bcl-2 expression played a minor role in oral tongue carcinoma. It had no significant correlation with tumour grade, stage and nodal metastasis. It also had no prognostic value on survival for patients who were treated by primary surgery.

Investigation of environmental factors for diagnosing malignant potential in oral epithelial dysplasia

A study was conducted in rats with early tongue carcinoma induced by 4-nitroquinoline 1-oxide (4NQO), in order to investigate the early diagnosis of malignant potential of epithelial dysplasia. The rat tongue lesions were classified by their severity into three groups corresponding to early cancer, dysplasia and no change. The grade of epithelial changes was determined according to 13 items of WHO Epithelial Dysplasia Criteria. The expression levels of p53 and Bcl-2 proteins were detected immunohistochemically, and apoptotic cells were detected using the TUNEL method. In addition, a p53 mutation by lesions was detected. The expression ratio of p53 protein was high in dysplasia, and the ratio of Bcl-2 protein was high in early cancer and dysplasia. The TUNEL-positive cells were observed primarily in the granular layers of the no change cells, and their numbers decreased as the cells shifted to the early cancer stage. The p53 mutation was detected using a microdissection method in dysplasia, where it was found in three out of nine lesions. All the mutations in dysplasia detected were on the same codon that was found to be mutated in the early cancer. These results indicate that the association between the p53 mutation and histological changes in carcinogenesis epithelial dysplasia is strong, and that both the identification of p53- and Bcl-2-positive epithelium, and decrease in the TUNEL positive ratio, were useful for the diagnosis of the malignant potential of precancerous lesions.

Deregulated Bag-1 protein expression in human oral squamous cell carcinomas and lymph node metastases

Bag-1 is an anti-apoptotic protein that promotes metastasis in some tumour cell types. To determine whether Bag-1 expression is altered in 64 oral squamous cell carcinomas, tumour samples were compared with 17 samples of normal oral epithelium. Normal oral epithelia had pronounced nuclear staining in the basal and maturation layers and weak cytoplasmic staining that was most pronounced in the basal and suprabasal layers. Oral squamous cell carcinomas demonstrated a tendency for reduced nuclear staining intensity (p=0.036). Cytoplasmic staining intensity was not significantly different between tumour and normal tissue. However, many tumours were observed to have less of a difference between nuclear staining intensity and cytoplasmic staining intensity than normal oral epithelium. Furthermore, in lymph node metastases, cytoplasmic Bag-1 staining was stronger in 8/13 cases than in corresponding primary tumours (p=0.021). Western blotting using nine oral primary carcinoma cell lines and four normal keratinocyte cultures showed that the isoforms Bag-1s, Bag-1M, and Bag-1L were expressed in normal and malignant oral epithelial cells. Bag-1L unique sequences were shown to adopt an exclusively nuclear, and predominantly nucleolar, localization by use of transiently transfected N-terminal Bag-1L-EGFP. However, levels of Bag-1L in carcinoma cells did not differ significantly from those of normal keratinocytes. Therefore the reduced nuclear staining observed in oral squamous cell carcinomas compared with normal epithelium may reflect changes in the localization of Bag-1 isoforms, rather than decreased expression of Bag-1L. Alterations in the relative proportions of Bag-1S, Bag-1M, and Bag-1L were detected in 6/9 oral carcinoma cell lines; 5/9 oral carcinoma cell lines had a significantly greater proportion of Bag-1M than normal keratinocytes and in another cell line, Bag-1L was significantly underrepresented. Overall, the results suggest that Bag-1 deregulation plays a role in oral carcinogenesis at two different stages: during primary carcinoma development and during lymph node metastasis.

The unexplained survival of cells in oral cancer: what is the role of p53?

In normal oral epithelium the cells divide, mature, differentiate, and die. This sequence is not normally followed in oral cancer. Instead, the death of the cells is somehow prevented, although the pathways toward cell death in normal oral epithelium and the defects in oral cancer are not well defined. However, several components in the system have been identified, and information on their interactions is becoming available. This review summarizes the evidence for cell death being due to apoptosis and the central role of the p53 gene product in its regulation. Areas for future research are also identified.

The immunohistochemical localization of Bax and Bcl-2 and their relation to apoptosis during amelogenesis in developing rat molars

Bax and Bcl-2 are members of a family of intracellular, membrane-associated proteins that regulate programmed cell death. It has been suggested that, when Bax predominates, programmed cell death is accelerated and the apoptosis inhibitory activity of Bcl-2 is suppressed. The present study was undertaken to immunohistochemically (IHC) localize Bax and Bcl-2 in the cells of the enamel organ during amelogenesis in rat molars. Also, apoptotic cells were detected by TUNEL staining. The IHC intense localization of Bcl-2 and light staining for Bax in the pre-ameloblasts suggest that apoptosis is inhibited in the proliferating pre-ameloblasts. This is consistent with an absence of TUNEL staining for apoptosis in these cells. However, in the late secretory and transition ameloblasts, and adjacent stratum intermedium, evidence of apoptosis of the ameloblasts was observed. Bax and Bcl-2 were co-localized in the proximal ends of late secretory, transition and early maturation-stage ameloblasts, but immunoreactivity for Bax markedly increased in the proximal ends of late secretory and transition ameloblasts, while the Bcl-2 staining appeared to be lighter. This suggests that Bax antagonized Bcl-2 function, limiting the ability of Bcl-2 to prolong cell survival. In the early maturation stage, Bax staining faded while the immunoreactivity for Bcl-2 increased. Evidence of distinct apoptosis was reduced in the early maturation stage ameloblasts. When related to the occurrence of apoptosis during amelogenesis, the relative intensity of expression of Bax and Bcl-2 changed in a pattern consistent with that observed in other cell lines. This indicates that these proteins play essential roles in the process of amelogenesis, as predicted by their proposed mechanisms of action in the control of apoptosis.

Bax/bcl-2: cellular modulator of apoptosis in feline skin and basal cell tumours

Bcl-2 and bax are two members of the BCL-2 gene family that play a prominent role in the regulation of apoptosis. Bax and bcl-2 expression were examined immunohistochemically in normal (healthy) feline skin and in 24 benign feline cutaneous basal cell tumours. The tumours were also examined for cellular proliferation by measurement of reactivity for the proliferation marker Ki-67, and for apoptosis by in-situ labelling for fragmented DNA. Bcl-2 was detected in normal basal epithelium and in 23 of 24 basal cell tumours. Bax was detected in both basal and suprabasal epithelium, but in only seven of 24 tumours. For tumours that expressed both bax and bcl-2, the bax:bcl-2 ratio was low. Neither bax nor bcl-2 expression was detected in 14 feline cutaneous squamous cell carcinomas. Basal cell tumours showed modest cellular proliferation (median, 17.5% Ki-67- reactive cells), but few (less than 1%) apoptotic cells. The slow, indolent growth of feline cutaneous basal cells in these benign skin tumours may be a response, at least in part, to opposing regulatory expressions of bcl-2 and bax.

Fas-induced apoptosis is a rare event in Sjögren's syndrome

The aim of this study was to perform a controlled in situ analysis on the incidence of apoptosis, investigate the expression of apoptosis-mediating proteins, and determine the frequency of apoptotic CD4+ and CD8+ T cells in Sjögren's syndrome (SS). The study was extended to patients with atrophy-fibrosis (AF) not related to SS, as well as to a control group. Immunohistochemistry and the terminal deoxynucleotidyl transferase mediated dUTP digoxigenin nick end labeling (TUNEL) method were applied to study the Fas and FasL expression and the incidence of apoptosis in salivary glands (SG) from patients with primary and secondary SS, AF, and controls. These methods were also combined to enable simultaneous detection of apoptotic and CD4+ or CD8+ T cells. Despite abundant expression of Fas and FasL in SS SG, apoptotic cells were not exceeding 1% in the foci of infiltrating mononuclear cells (IMC). Double staining showed that the frequency of apoptosis was low among both CD4+ and CD8+ T cells. Only a few TUNEL+ epithelial cells were found in all patient groups. Fas was expressed predominantly on SS IMC, single SS epithelial cells, and a few normal acinar cells, but not in AF SG. Although FasL was present on SS and AF IMC and epithelial cells, it was rarely detected in normal tissue. Consequently we demonstrate that Fas-induced apoptosis among SS SG is a rare event. Our findings support an earlier hypothesis indicating that IMC seem to be able to escape apoptosis, resulting in foci of inflammatory cells. Notably, however, no obvious correlation can be drawn to previous studies where a high incidence of apoptosis of epithelial cells was proposed as an important mechanism leading to decreased glandular function, which is a hallmark of SS.

Bcl-2 expression in sequential biopsies of potentially malignant oral mucosal lesions assessed by immunocytochemistry

OBJECTIVE

To examine, for the first time Bcl-2 expression in sequential (autogenous) oral mucosal biopsies taken from the same sites in a gender, risk-factor matched, Caucasoid sample, over a 21-year period.

DESIGN

Retrospective immunocytochemical longitudinal study of archival serial biopsies.

MATERIALS AND METHODS

Computer records were used to identify biopsy specimens derived from 12 patients. These were divided into four groups: (1) Histologically innocuous lesions which remained histologically innocuous. (2) Dysplastic lesions which remained dysplastic. (3) Histologically innocuous lesions which later progressed to squamous cell carcinoma (SCC). (4) Dysplastic lesions which later progressed to SCC. This represented 65 biopsies in total. Bcl-2 expression was studied using mouse antihuman BCL-2 oncoprotein clone 124 (Dako, Denmark).

RESULTS

Generally, there was a lack of Bcl-2 immunoreactivity in the epithelium, with one exception in dysplastic epithelium from a group (3) patient.

CONCLUSION

These findings suggest that in our series, Bcl-2 is not expressed early in oral premalignant lesions and appears to contradict previous reports. Possible explanations for this disparity are considered.