Sections Of Oral Squamous Cell Carcinoma Research Articles

Expression of syndecan-1 in different grades of oral squamous cell carcinoma: An immunohistochemical study.

Syndecans are a family of transmembrane proteins, belonging to heparin sulphate proteoglycan family and are localized entirely to the epithelial cells with the stratified squamous epithelia. They are involved in cell-cell adhesion and interaction with the extracellular matrix and play a critical role in cell growth, differentiation, cell morphology, and migration. The down regulation of syndecan-1 indicates loss of cellular adhesion and possibility of invasion. The present study is aimed to evaluate the difference in immunohistochemical expression of syndecan-1 in different grades of oral squamous cell carcinoma (OSCC) patients and control group. The present study consists of 42 cases of paraffin-embedded tissue sections of OSCC; 14 well differentiated, 14 moderately differentiated, and 14 poorly differentiated. As a control, 10 paraffin-embedded tissue sections of unaffected oral mucosa were used. The sections were stained for immunohistochemical expression of syndecan -1. The intensity of staining was scored. The immunohistochemistry scores for each sample were obtained by Tissue Quant software. Statistical analysis revealed that there was a significant decrease in intensity of staining between normal and different grades of OSCC. This study shows that as cellular differentiation was lost, syndecan-1 expression was less. This provides an insight and understanding of the pathophysiology of the invasive process of OSCC and helps in establishing the prognostic link.

Elucidating the immunohistochemistry of Nanog: A transcription marker in the oral squamous cell carcinoma with emphasis on its origin as embryonic stem cell.

Nanog is a key transcription factor regulating pluripotency in mammalian early embryos and pluripotent stem cells. Nanog plays a central role in pluripotency and forms autoregulatory loops to maintain ESC (embryonic stem cell) identity. Oral squamous cell carcinoma (OSCC) is an extensively studied malignancy that occurs due to accumulated genetic and epigenetic changes. Hence, the current study was done to evaluate role of Nanog in OSCC. The present study was done to evaluate Nanog role in OSCC. Thirty normal subjects and 30 patients of oral squamous cell carcinoma (OSCC) were included in study. The cases were staged clinically based on tumour node metastasis (TNM) staging and graded histopathologically using modified Broder's grading system. Thirty tissue sections of OSCC were subjected to immunohistochemistry (IHC) with Nanog antibody. Random fields were chosen and 300 cells were counted in five areas and mean percentage of immunopositive cells were calculated. The results were analysed using ANOVA test. The results demonstrated a statistically significant difference between normal subjects and in patients with OSCC with respect to mean of IHC score (P = 0.0001*). High mean values for Nanog in tissue with OSCC in both histopathological (P = 0.0001*) and clinical grading (P = 0.0276*) with statistically significant result were observed. The increased expression of Nanog in patients with OSCC was statistically significant, suggesting its role as diagnostic biomarker. Statistically significant result with respect to clinical staging and histopathological grading of Nanog expression in patients with OSCC suggests its role as prognostic biomarker also.

P2Y Purinergic Receptor Signaling in Oral Squamous Cell Carcinoma Cell Lines and Its Role in Proliferation and Cisplatin-Mediated Apoptosis

Treatment of advanced stage oral squamous cell carcinoma (OSCC) often involves the use of chemotherapeutic agents, such as cisplatin. However, its use often results in therapeutic failure due to chemoresistance. This study focused on a class of purinergic receptors, namely P2Y, which are activated via interaction with extracellular nucleotides. The functional effects of P2Y receptor activation in OSCC cell lines as well as the signaling pathways involved were investigated. The expression of P2Y2 receptors in histological sections of OSCC was studied due to its association with cancer. Activation of MAPK pathways via extracellular nucleotides were studied in OSCC cell lines, along with downstream effects such as proliferation and cisplatin-mediated apoptosis. Immunohistochemical staining of OSCC tissue samples showed loss of P2Y2 expression as the disease progressed. Western blotting identified different MAPK signaling pathways were activated by extracellular nucleotides. Bromodeoxyuridine proliferation assays showed increased cellular proliferation in the OSCC cell lines H400 (p < 0.001) and SAS (p < 0.001) after 24 h treatment with ATP. However, the ability of extracellular nucleotides to activate multiple P2Y receptor subtypes may indicate the involvement of other subtypes aside from P2Y2. Cisplatin-mediated apoptosis was enhanced in SAS cells co-treated with ATP (p < 0.001), while H376 (p < 0.001) showed reduction in the number of apoptotic cells and no significant changes were observed in H103. This study concluded that extracellular nucleotide on OSCC cell lines with different characterizations had varied downstream effects, which suggests the use of targeted therapy to specific individuals.

Detection of Helicobacter pylori in oral squamous cell carcinoma using modified Giemsa stain: A new diagnostic approach.

Oral squamous cell carcinoma (OSCC) is the sixth most common cancer worldwide. It is mainly known to be caused by tobacco in various forms and also due to viral, fungal infection and poor oral hygiene, etc. Poor oral hygiene leads to colonization of pathogenic bacteria including Helicobacter pylori. It seems that the presence of H. pylori might be a risk factor for developing oral cancer. The successful attempt was made to detect H. pylori in diagnosed specimens of OSCC using Warthin-starry and Giemsa stains in our department. The modified Giemsa stain is the method of choice because it is sensitive, cheap, easy to perform, faster, and reproducible. The aim of this study is to detect H. pylori in various grades of OSCC using modified Giemsa stain. Thirty cases of various grades of OSCC were selected from the archives of the department. Five-micrometer-thick paraffin-embedded tissue sections of these cases were taken and stained with modified Giemsa and were studied under ×100 magnification. All the tissue sections studied were positive for H. pylori bacteria. Our study showed a significant presence of H. pylori in histological sections of OSCC, and it seems likely that the presence of H. pylori might be a risk factor for the developing oral lesions such as oral cancer. Early detection and eradication of H. pylori in the oral cavity, especially in high-risk patients, might prevent its harmful consequences.

Oral Squamous Cell Carcinoma Contributes to Differentiation of Monocyte-Derived Tumor-Associated Macrophages via PAI-1 and IL-8 Production.

Tumor-associated macrophages (TAMs) promote cancer cell proliferation and metastasis, as well as anti-tumor immune suppression. Recent studies have shown that tumors enhance the recruitment and differentiation of TAMs, but the detailed mechanisms have not been clarified. We thus examined the influence of cancer cells on the differentiation of monocytes to TAM subsets, including CD163+, CD204+, and CD206+ cells, in oral squamous cell carcinoma (OSCC) using immunohistochemistry, flow cytometry, and a cytokine array. Furthermore, we investigated the effect of OSCC cells (HSC-2, SQUU-A, and SQUU-B cells) on the differentiation of purified CD14+ cells to TAM subsets. The localization patterns of CD163+, CD204+, and CD206+ in OSCC sections were quite different. The expression of CD206 on CD14+ cells was significantly increased after the co-culture with OSCC cell lines, while the expressions of CD163 and CD204 on CD14+ cells showed no change. High concentrations of plasminogen activator inhibitor-1 (PAI-1) and interleukin-8 (IL-8) were detected in the conditioned medium of OSCC cell lines. PAI-1 and IL-8 stimulated CD14+ cells to express CD206. Moreover, there were positive correlations among the numbers of CD206+, PAI-1+, and IL-8+ cells in OSCC sections. These results suggest that PAI-1 and IL-8 produced by OSCC contribute to the differentiation of monocytes to CD206+ TAMs.

PERINEURAL INVASION IN ORAL SQUAMOUS CELL CARCINOMA: INCIDENCE, CLINICAL IMPACT AND MOLECULAR INSIGHT

<h3>Background</h3> Perineural invasion (PNI) has been associated with poor prognosis in oral squamous cell carcinoma (OSCC). Nerve growth factor (NGF) and its receptor tyrosine kinase A (TrkA) may play a role in PNI in OSCC. <h3>Objective</h3> To characterize the incidence and prognostic correlation of PNI in OSCC and to determine whether NGF and TrkA expressions could be used as biological markers for PNI in OSCC. <h3>Methods</h3> A retrospective review of pathology reports of 430 patients with OSCC treated from 1992 to 2014 in Tayside, Scotland, and followed for 5 years or until death was undertaken. The expression of NGF and TrkA was assessed with immunohistochemistry in 132 tissue sections of OSCC. <h3>Results</h3> PNI was identified in 17.4% of OSCC. High expression of NGF and TrkA was seen in 84% and 92% of OSCC, respectively. PNI-positive OSCC expressed NGF and TrkA with greater frequency than PNI-negative OSCC (<i>P</i> < .05). PNI and high expression of NGF were associated significantly with pain in OSCC (<i>P</i> < .05). PNI-positive OSCC and high NGF/TrkA expression exhibited a greater potential for lymphovascular invasion and depth of invasion >4 mm (<i>P</i> < .05). PNI was significantly associated with advanced size, nodal metastasis, poor differentiation, and stage IV tumors (<i>P</i> < .05). PNI correlated significantly with disease-specific survival in OSCC (<i>P</i> < .05). <h3>Conclusions</h3> Higher level of expression of NGF and TrkA many predict PNI and therefore may be considered as biological markers for PNI in OSCC. Pain could be a predictive for PNI and NGF overexpression. PNI and NGF expression can predict the aggressiveness and prognosis of OSCC.

Tumor Microenvironment, HLA Class I and APM Expression in HPV-Negative Oral Squamous Cell Carcinoma.

Simple SummaryOral squamous cell carcinoma has developed different strategies to escape from T-cell-mediated immune surveillance, which is mediated by changes in the composition of cellular and soluble components of the tumor microenvironment as well as an impaired expression of molecules of the antigen processing machinery leading to a downregulation of HLA class I surface antigens. In depth characterization of these escape mechanisms might help to develop strategies to overcome this tolerance. In this study, human papilloma virus negative oral squamous cell carcinoma lesions were analyzed regarding the protein expression of major components of the HLA class I antigen processing/presentation pathway in correlation to the intra-tumoral immune cell composition, IFN-γ signaling and clinical parameters, which was further confirmed by bioinformatics analyses of datasets obtained from The Cancer Genome Atlas. This novel knowledge could be used for optimizing the design of immunotherapeutic approaches of this disease.Progression of oral squamous cell carcinoma (OSCC) has been associated with an escape of tumor cells from the host immune surveillance due to an increased knowledge of its underlying molecular mechanisms and its modulation by the tumor microenvironment and immune cell repertoire. In this study, the expression of HLA class I (HLA-I) antigens and of components of the antigen processing machinery (APM) was analyzed in 160 pathologically classified human papilloma virus (HPV)-negative OSCC lesions and correlated to the intra-tumoral immune cell response, IFN-γ signaling and to the patient’s outcome. A heterogeneous but predominantly lower constitutive protein expression of HLA-I APM components was found in OSCC sections when compared to non-neoplastic cells. Tumoral HLA-I APM component expression was further categorized into the three major phenotypes HLA-Ihigh/APMhigh, HLA-Ilow/APMlow and HLA-Idiscordant high/low/APMhigh. In the HLA-Ihigh/APMhigh group, the highest frequency of intra-tumoral CD8+ T cells and lowest number of CD8+ T cells close to FoxP3+ cells were found. Patients within this group presented the most unfavorable survival, which was significantly evident in stage T2 tumors. Despite a correlation with the number of intra-tumoral CD8+ T cells, tumoral JAK1 expression as a surrogate marker for IFN-γ signaling was not associated with HLA-I/APM expression. Thus, the presented findings strongly indicate the presence of additional factors involved in the immunomodulatory process of HPV-negative OSCC with a possible tumor-burden-dependent complex network of immune escape mechanisms beyond HLA-I/APM components and T cell infiltration in this tumor entity.

The budding and depth of invasion model in oral cancer: A systematic review and meta-analysis.

Tumour budding (B) and depth of invasion (D) have both been reported as promising prognostic markers in oral squamous cell carcinoma (OSCC). This meta-analysis assessed the prognostic value of the tumour budding and depth of invasion combination (BD model) in OSCC. Databases including Ovid MEDLINE, PubMed, Scopus and Web of Science were searched for articles that studied the BD model as a prognosticator in OSCC. PICO search strategy was "In OSCC patients, does BD model have a prognostic power?" We used the reporting recommendations for tumour marker prognostic studies (REMARK) criteria to evaluate the quality of studies eligible for systematic review and meta-analysis. Nine studies were relevant as they analysed the BD model for prognostication of OSCC. These studies used either haematoxylin and eosin (HE) or pan-cytokeratin (PCK)-stained resected sections of OSCC. Our meta-analysis showed a significant association of BD model with OSCC disease-free survival (hazard ratio=2.02; 95% confidence interval=1.44-2.85). The BD model is a simple and reliable prognostic indicator for OSCC. Evaluation of the BD model from HE- or PCK-stained sections could facilitate individualized treatment planning for OSCC patients.

Effectiveness of crystal violet stain for localization of mitotic activity in oral squamous cell carcinoma

Background: Mitotic figure counting is simplest and oldest method for determining proliferative activity of cell. It is considered as one of the important diagnostic aid in cancer pathology. Though advanced methods to evaluate dysplastic features are more precise and definite but expense and time makes them less practicable for routine use. Therefore an effort was made to use economical as well as simple approach involving crystal violet stain (1%) to study the mitotic figures in oral squamous cell carcinoma.&#x0D; Materials and Methods: This descriptive research included samples, consisting of thirty three cases of the oral squamous cell carcinoma (OSCC). Representative sections were stained with H&amp;E stain and 1% crystal violet stain respectively. The stained sections were viewed under optical microscope to count mitotic figures for evaluating the effectiveness of 1% crystal violet stain. Data obtained was statistically analyzed by using sample t-test.&#x0D; Results: There was noteworthy increase in the mean mitotic count among the crystal violet stained sections of OSCC in contrast to the OSCC sections stained with H&amp;E (P = 0.00).&#x0D; Conclusion:1% Crystal violet stain can be considered as one of the optimum stains to observe the mitotic figure. Practice of staining with 1% crystal violet during routine histopathological procedures will be cost effective and may be used as a selective stain.

Tumor budding - A promising prognostic histopathological parameter in oral squamous cell carcinoma - A comparative immunohistochemical study.

Introduction:The majority of the head and neck squamous cell carcinomas (HNSCC) occur in the oral cavity. Even with advances in cancer therapy only minor improvements in the survival of HNSCC patients have taken place and approximately 350,000 patients die annually of HNSCC worldwide. Tumor budding (TB) is a novel and promising histo-morphological parameter that has been studied in many cancers. The presence of TB is associated with lymph node and distant metastasis as well as poor survival, independently of the applied scoring system. The depth of tumor invasion (D) measured from the surface of the tumor to the deepest point of invasion is also an important prognostic parameter for oral squamous cell carcinoma (OSCC) with a cutoff point of 4 mm. Both taken together constitute BD model and it has also been found to be an independent prognostic factor for patients with OSCC. Therefore, it would be highly beneficial to evaluate TB and BD model in routine histopathological reporting.Aims and Objectives:This study aims to compare the detection of TB in hematoxylin-eosin and pan-cytokeratin stained immune-histochemical sections of OSCC and also to evaluate whether BD score can serve as a reliable prognostic indicator for OSCC.Methodology:A total of 30 formalin-fixed, paraffin-embedded tissue blocks of clinically and histopathologically diagnosed cases of OSCC were retrieved. One section was stained with hematoxylin and eosin and the other was processed for pancytokeratin immunohistochemistry to evaluate tumor buds. Depth of invasion (D) was also evaluated to achieve the BD score.Results:Statistical significance (P < 0.001) was noted between TB score evaluated in hematoxylin and eosin (H&E) and pancytokeratin stained sections. There was no statistical significance between age, gender, site of lesion, clinical staging, survival and BD score.Conclusion:Immunohistochemical analysis of TB is superior to H&E staining in detection of tumor buds at the tumor invasive front.

Role of E-cadherin in Progression of Oral Squamous Cell Carcinoma: A Retrospective Immunohistochemical Study

The aim of present study was to assess the role of E-cadherin in oral carcinogenesis by comparing their expressions in normal oral mucosa, oral epithelial dysplasia (OED), and oral squamous cell carcinoma (OSCC). To elucidate the pattern of E-cadherin expression in oral carcinogenesis, 21 archival cases of formalin-fixed paraffin-embedded sections of OSCC, 21 OED, and 7 normal oral mucosa samples as control were used for the study. We observed reduction/loss of E-cadherin in membranous expression pattern and staining intensity with progression from dysplasia to oral cancer. A decrease in staining intensity and loss of E-cadherin membranous expression were noted from dysplasia to carcinoma, suggesting its role as a tumor suppressor gene. E-cadherin can be used as a biomarker to assess and evaluate the progression and prognosis of oral dysplastic lesions and OSCC.

Expression of TIMP-2 in HPV-16 infected oral squamous cell carcinoma in patients in Iraq

Aim: To determine the expression of tissue inhibitors of metalloproteinases (TIMP-2) in oral squamous cell carcinoma (OSCC) and the difference in its expression level between positive and negative HPV-16 (human papilloma virus- 16) OSCC patients. Methods: This study was conducted on 33 biopsies obtained from patients with OSCC and 10 normal oral mucosa as controls. In situ hybridization (ISH) was used to investigate the presence of HPV-16, while immunohistochemistry (IHC) was used to estimate the expression level of TIMP-2. Results: The TIMP-2 was expressed in 27 (81.8%) of OSCC sections with no significant difference between its expression level in HPV-16 positive and HPV-16 negative OSCC cases (p=0.058). TIMP-2 was found to be highly expressed in OSCC sections, and the presence of HPV was not related to its overexpression. Conclusions: The percentage of samples that appeared to accommodate detectable HPV-16 was high, but no significant difference was observed in relation to TIMP-2 expression level. Future studies with a larger number of patients are highly recommended to address the possible association between TIMp-2 and OSCC positive HPV-16.

Multiple cells express interleukin 17 in oral squamous cell carcinoma.

Interleukin (IL)-17 is a pro-inflammatory cytokine with pro- and antitumour effects. The aim of this study was to investigate the presence and potential sources of IL-17 in oral squamous cell carcinoma (OSCC). Immunohistochemistry was used to label and compare IL-17+ cells in the tissue sections of OSCC and inflammatory controls (IC), n = 14 for both. In OSCC, the comparison was made between the number of IL-17+ cells in the tumoral islands (TI), tumour-stroma interface (TS) and more distant stroma (DS). Cells expressing IL-17 were identified using double-labelling immunofluorescence and examined using laser scanning microscopy. The production of IL-17 from tumour cells was determined in the culture supernatants of OSCC cell lines, SCC4, SCC15 and SCC25, using sandwich ELISA. Significantly more IL-17+ cells were observed in OSCC compared with IC (Mann-Whitney, P < 0.0001). In OSCC, the numbers of IL-17+ cells were not significantly different in three compartments, TI, TS and DS (one-way ANOVA, P > 0.05). However, the TI had significantly fewer IL-17+ cells than the combined stroma (both TS and DS together, Mann-Whitney, P < 0.01). Laser scanning microscopy revealed helper T cells, cytotoxic T cells, macrophages and mast cells co-expressed IL-17. ELISA experiments did not detect IL-17 in the supernatants of OSCC cell lines. Although the tumour cells themselves did not express IL-17, a range of cell types did, suggesting multiple cellular sources for IL-17 in OSCC. The spatial distribution of IL-17+ cells suggests specific interactions with cells within the tumour microenvironment, implying that IL-17+ cells are likely to play a role in the pathogenesis of OSCC.

Overexpression of HDAC9 promotes oral squamous cell carcinoma growth, regulates cell cycle progression, and inhibits apoptosis.

Histone deacetylases (HDACs) are a family of deacetylase enzymes that regulate the acetylation state of histones and a variety of other non-histone proteins including key oncogenic and tumor suppressor proteins, which modulates chromatin conformation, leading to regulation of gene expression. HDACs has been grouped into classes I-IV and histone deacetylase 9 (HDAC9) belongs to class IIa which exhibits tissue-specific expression. Recent reports have demonstrated both pro-oncogenic and tumor suppressive role for HDAC9 in different cancers; however, its role in OSCC remains elusive. Here, we investigated the role of HDAC9 in pathogenesis of oral squamous cell carcinoma (OSCC). Our data showed significantly increased mRNA and protein expression of HDAC9 in clinical OSCC samples and UPCI-SCC-116 cells as compared to normal counterpart. Kaplan-Meier analysis showed that the patients with high-level of HDAC9 expression had significantly reduced overall survival than those with low-level of HDAC9 expression (p=0.034). Knockdown of HDAC9 using siRNA interference suppressed cell proliferation, increased apoptosis, and induced G0/G1 cell cycle arrest in UPCI-SCC-116 cells. Immunofluorescence analysis showed increased nuclear localization of HDAC9 in frozen OSCC sections, and indicative of active HDAC9 that may transcriptionally repress its downstream target genes. Subsequent investigation revealed that overexpression of HDAC9 contributes to OSCC carcinogenesis via targeting a transcription factor, MEF2D, and NR4A1/Nur77, a pro-apoptotic MEF2 target.

To analyze the concomitant expression of human papillomavirus-16 in the pathogenetic model of p53-dependant pathway in oral squamous cell carcinoma.

Background:Oral squamous cell carcinoma (OSCC) accounts for 90% of all primary oral malignancies. Association between human papillomavirus (HPV) as a risk factor of cervical cancer is well known; there is a need to widen the knowledge for its role in oral cancer development. The viral E6 protein of HPV binds to p53 making it nonfunctional.Aims and Objective:To study mutated/wild type p53 expression using immunohistochemistry and detect HPV-16 presence using polymerase chain reaction (PCR), in OSCC and correlating their expression.Materials and Methods:Immunohistochemical staining for p53 molecule in 24 sections of OSCC followed by DNA extraction of the cases using qiagen extraction kit and subsequent HPV-16 detection using PCR technique.Statistical Analysis:The data were analysed using SPSS software version 19.Results:Out of 24 cases of OSCC, twenty cases were positive for P 53 expression and four cases were negative for P 53 expression. Out of the four negative cases, one case was detected positive for HPV-16.Conclusion:HPV infection along with p53 expression helps in understanding its exact pathogenesis which further helps in expanding our spectrum of therapeutic modalities

Expression of MUC1 mucin in potentially malignant disorders, oral squamous cell carcinoma and normal oral mucosa: An immunohistochemical study.

Background:Mucins alteration in glycosylation is associated with the development and progression of malignant diseases. Therefore, mucins are used as valuable markers to distinguish normal and disease conditions. Many studies on MUC1 expression have been conducted on variety of neoplastic lesions other than head and neck region. None of the study has made an attempt to show its significance in potentially malignant disorders (PMDs) and oral squamous cell carcinoma (OSCC). Hence, ours is one of the pioneer studies done to assess and evaluate the same.Aims:This study aims to compare and correlate the expression of MUC1 mucin protein in normal oral mucosa (NOM), PMD's and OSCC by immunohistochemical method.Materials and Methods:Institutional study, archived tissue sections of OSCC (n = 20), PMD's (n = 20) and NOM (n = 20) were immunostained for MUC1 mucin and percentage of positive cells evaluated. Results obtained were statistically analyzed using Kruskal–Wallis test, Mann–Whitney test and Student's t-test.Results:The mean MUC1 mucin positive cells in the study groups were as follows, 40% in OSCC, 28% in PMD's and 0.75% in NOM. Higher mean immunohistochemical score was observed in OSCC group followed by PMD's group and NOM group. The difference in immunohistochemical score among the groups was found to be statistically significant (P < 0.001).Conclusion:The result of the current study suggests that determination of MUC1 mucin expression may be a parameter in the diagnosis of malignant behavior of PMD's to OSCC. MUC1 mucin expression may be a useful diagnostic marker for prediction of the invasive/metastatic potential of OSCC.

Incidence of Mast Cells in Oral Squamous Cell Carcinoma: A Short Study

Mast cells are regarded as complex and multifunctional cells, playing a significant role in immunopathology and a substantial role in tumor angiogenesis. Angiogenesis is a complex process that is tightly regulated by various growth factors in which mast cells act directly by releasing angiogenic factors and henceforth promoting tumor growth and metastasis. The aim of this study is to evaluate the number of mast cells in tissue sections of oral squamous cell carcinoma (OSCC) in comparison with normal mucosa. A total of 40 cases (20 OSCC and 20 normal mucosa) were stained with 1% toluidine blue and the quantitative analysis was done by using light microscope under 400x magnification. A significant increase in the mast cell count was observed in the sections of OSCC when compared to normal mucosa suggesting their contributing role in tumor growth and progression.

Immunohistochemical detection of p53 and p63 in oral squamous cell carcinoma, oral leukoplakia, and oral submucous fibrosis

Oral squamous cell carcinoma (OSCC) may be preceded by potentially malignant disorders such as leukoplakia and oral submucous fibrosis (OSF). p63 in concert with p53 regulates cell proliferation and differentiation and may have a role in potentially malignant and malignant lesions of the oral cavity. The aim of the study was to evaluate and compare the expression of p53 and p63 proteins in OSCC, leukoplakia, and OSF by immunohistochemistry (IHC). Tissue sections of OSCC (n=20), leukoplakia (n=20), OSF (n=20) and normal oral mucosa (n=10) were stained with p53 and p63 antibodies by IHC. Mean labeling index (LI) among the study groups were compared using the Kruskal-Wallis test. The mean LI of p53 for OSCC, leukoplakia, OSF, and normal mucosa were 56.9±21.3, 37.6±12.6, 34.6±8.7 and 15.1±9, while mean LI of p63 were 56.8±19.6, 42.3±10.5, 32.8±12.1, and 26.4±9.4. The mean LI of p53 and p63 were significantly higher in OSCC, leukoplakia and OSF compared to normal mucosa (P<0.01; P<0.01). The significant increase in expression of p53 and p63 proteins in OSCC, leukoplakia, and OSF suggests their role as surrogate markers of malignant transformation.

Significance of heterogeneous nuclear ribonucleoprotein B1 as a new early detection marker for oral squamous cell carcinoma.

The development of an early tumor detection marker for oral cancer is an obvious need due to the high recurrence rate and poor survival rate. Based on our previous report that overexpression of heterogeneous nuclear ribonucleoprotein (hnRNP) B1 protein was found in 100% of squamous cell carcinomas of human lung, we applied the same immunohistochemical method, using anti‐hnRNP B1 antibody, to human oral squamous cell carcinoma (OSCC). Seven human tissue sections of OSCC showed strong staining with anti‐hnRNP B1 antibody, and hnRNP B1 protein of 37 kDa was identified in protein fractions isolated from six of the cancerous tissue sections, while it was not found in adjacent noncancerous tissue. Moreover, three non‐homogeneous (nodular) leukoplakia sections showed significant anti‐hnRNP B1 staining. The results suggest that this antibody detects precancerous lesions as well as advanced lesions (stages I to IV) of OSCC. We also present positive results of cytodiagnosis for two smear specimens. All of the above results indicate that hnRNP B1 is a new and useful marker for early detection of OSCC.