Analysis of the Ki-67 antigen at the invasive tumour front of human oral squamous cell carcinoma

A review: early detection of oral cancer biomarkers using microfluidic colorimetric point-of-care devices

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancers. OSCC constitutes 90% of the head and neck malignancies. The delayed identification of oral cancer is the primary cause of ineffective medical treatment. To address this issue, low-cost, reliable point-of-care devices that can be utilized for large-scale screening, even in low-resource settings, including rural areas and primary healthcare centers, are of great interest. Herein, a comprehensive analysis of numerous salivary biomarkers that exhibit significant variations in concentration between individuals with oral cancer and those without is given. Furthermore, the article explores several point-of-care devices that exhibit potential in the realm of oral cancer detection. The biomarkers are discussed with a focus on their structural characteristics and role in oral cancer progression. The devices based on colorimetry and microfluidics are discussed in detail, considering their compliance with the 'REASSURED' criteria given by the World Health Organization (WHO) and suitability for mass screening in low-resource settings. Finally, the discourse revolves around the fundamental aspects pertaining to the advancement of multiplex, cost-effective point-of-care devices designed for widespread screening purposes.

Exploring the osteogenic potential of semisynthetic triterpenes from Combretum leprosum: An in vitro and in silico study

Combretum leprosum Mart. is a plant of the Combretaceae family, widely distributed in the Northeast region of Brazil, popularly used as an anti-inflammatory agent, and rich in triterpenes. This study evaluated in vitro and in silico potential osteogenic of two semisynthetic triterpenes (CL-P2 and CL-P2A) obtained from the pentacyclic triterpene 3β,6β,16β-trihydroxylup-20(29)-ene (CL-1) isolated from C. leprosum. Assays were carried out in cultured murine osteoblasts (OFCOL II), first investigating the possible toxicity of the compounds on these cells through viability assays (MTT). Cell proliferation and activation were investigated by immunohistochemical evaluation of Ki-67, bone alkaline phosphatase (ALP) activity, and mineralization test by Von Kossa. Molecular docking analysis was performed to predict the binding affinity of CL-P2 and CL-P2A to target proteins involved in the regulation of osteogenesis, including: bone morphogenetic protein 2 (BMP-2), proteins related to Wingless-related integration (WNT) pathway (Low-density lipoprotein receptor-related protein 6-LRP6 and sclerostin-SOST), and receptor activator of nuclear factor (NF)-kB-ligand (RANK-L). Next, Western Blot and immunofluorescence investigated BMP-2, WNT, RANK-L, and OPG protein expressions in cultured murine osteoblasts (OFCOL II). None of the CL-P2 and CL-P2A concentrations were toxic to osteoblasts. Increased cell proliferation, ALP activity, and bone mineralization were observed. Molecular docking assays demonstrated interactions with BMP-2, LRP6, SOST, and RANK-L/OPG. There was observed increased expression of BMP-2, WNT, and RANK-L/OPG proteins. These results suggest, for the first time, the osteogenic potential of CL-P2 and CL-P2A.

Preoperative Prediction of the Aggressiveness of Oral Tongue Squamous Cell Carcinoma with Quantitative Parameters from Dual-Energy Computed Tomography

Objectives

To determine whether quantitative parameters derived from dual-energy computed tomography (DECT) were predictive of the aggressiveness of oral tongue squamous cell carcinoma (OTSCC) including the pathologic stages, histologic differentiation, lymph node status, and perineural invasion (PNI).

Methods

Between August 2019 and March 2021, 93 patients (mean age, 54.6 ± 13.8 years; 66 men) with pathologically diagnosed OTSCC were enrolled in this prospective study. Preoperative DECT was performed and quantitative parameters (e.g., slope of the spectral Hounsfield unit curve [λ_Hu], normalized iodine concentration [nIC], normalized effective atomic number [nZ_eff], and normalized electron density [nRho]) were measured on arterial phase (AP) and venous phase (VP) DECT imaging. Quantitative parameters from DECT were compared between patients with different pathologic stages, histologic differentiation, lymph node statuses, and perineural invasion statuses. Logistic regression analysis was utilized to assess independent parameters and the diagnostic performance was analyzed by the receiver operating characteristic curves (ROC).

Results

λ_Hu and nIC in AP and λ_Hu, nZ_eff, and nIC in VP were significantly lower in stage III–IV lesions than in stage I–II lesions (p < 0.001 to 0.024). λ_Hu in VP was an independent predictor of tumor stage with an odds ratio (OR) of 0.29, and area under the curve (AUC) of 0.80. λ_Hu and nIC were higher in well-differentiated lesions than in poorly differentiated lesions (p < 0.001 to 0.021). The nIC in VP was an independent predictor of histologic differentiation with OR of 0.31, and AUC of 0.78. λ_Hu and nIC in VP were lower in OTSCCs with lymph node metastasis than those without metastasis (p < 0.001 to 0.005). λ_Hu in VP was the independent predictor of lymph node status with OR of 0.42, and AUC of 0.74. No significant difference was found between OTSCCs without PNI and those with PNI in terms of the quantitative DECT parameters.

Conclusion

DECT can be a complementary means for the preoperative prediction of the aggressiveness of OTSCC.

Ki67 Labelling Index predicts clinical outcome and survival in oral squamous cell carcinoma

OBJECTIVE

To investigate the Ki 67 expression and its correlation with clinicopathological features and 3 years as well as 5 years survival rate in oral squamous cell carcinoma (OSCC).

METHODOLOGY

Total 217cases of OSCC primarily treated with surgery with or without radiation were included. All patients were followed up for 3 years and 150 were followed up of 5 years for disease free survival. The immunohistochemistry was carried out on neutral buffered formalin fixed paraffin embedded tissue to evaluate the expression of Ki67.

RESULTS

The Ki67 labeling index (LI) was significantly higher with respect to adverse clinicopathological parameters such as histopathological grading (p<0.001), clinical TNM staging (p<0.001) and nodal metastasis (p<0.001). The OSCC patients survived for less than 3 and 5 years were showed significantly higher Ki67 LI as compared to diseases free survived more than 3 and 5 years(p<0.001). The three years survival rate of OSCC patient significantly higher with low Ki67 LI (≤45) 96.2%, followed by moderate Ki67 LI (46 to 60) 60.7% and high Ki67 LI (≥61) 37.7% (p<0.001). The five years survival rate of OSCC patient statistically significantly higher with low Ki67 LI (≤45)93.3%, followed by moderate Ki67 LI (46 to 60) 46.8% and Ki67 LI (≥61) 23.3% (p<0.001).

CONCLUSION

The measurement of cell proliferative activity by using Ki67 antigen expression in individual OSCC might provide unique, predictive information on clinical outcome, prognosis and deciding treatment modalities in OSCC.

Role of miR153 and miR455-5p Expression in Oral Squamous Cell Carcinoma Isolated from Plasma

Background:

Despite the notable advances in modern surgery and radiotherapy,no significant increase in the five year survival rate of oral squamous cell carcinoma has been reported. Collecting evidence demonstrates that miR 153 and miR 455-5p play a key role in growth and progression of oral cancer. Early detection of OSCC is important for enhancing patient quality of life and clinical treatment.For this reason, biomarkers or tumour markers offer an opportunity to intervene and avoid development of oral cancer.

Methods:

A total of 50 blood samples from patients from both genders (25 OSCC and 25 healthy people/control groups) were obtained to determine the expression of miR153 and miR455-5p using Real time Polymerase chain reaction and t test.

Results:

In general by using the formula Δ ct, it is evident that the miR 153 expression in peripheral blood is lower in patients than in healthy individuals (1.97) while the miR 455-5p expression in peripheral blood is higher in patients than in healthy individuals (2.56).

Conclusion:

We conclude that miR153 and miR 455-5p expression in serum can function as a diagnostic screening test for the early detection of oral squamous cell carcinoma.

An Immunohistochemical Study Showing Ki-67 as an Analytical Marker in Oral Malignant and Premalignant Lesions

Introduction

Ki-67 is a nuclear protein. It is a proliferation marker that has an essential function in tumorigenesis due to its positive connection with tumor expansion.

Aim

The aim of this study was to evaluate the articulation of Ki‑67 as prognostic marker in various grades of oral epithelial dysplasia (OED) and in oral squamous cell carcinoma (OSCC).

Materials and Methods

A total of 100 histologically affirmed samples of normal oral mucosa (NOM), OED, and OSCC were divided into three groups-Group I (10 samples of normal oral mucosa), Group II (45 samples of OED), Group III (45 samples of OSCC). Routine hematoxylin and eosin and immunohistochemical staining with Ki-67 monoclonal antibody were carried out in all the samples.

Results

Within Group I, articulation of Ki-67 was constrained to the basal layers. In Group II, cells showing positive expression of Ki-67 were available in the basal, suprabasal, and spinous layers. Cells showing positive expression of Ki-67 among well-differentiated OSCC were presented mainly in the periphery of the tumor nests; in moderately differentiated OSCC, cells were located in both peripheral and part of a center of the tumor nests; and in most cases of poorly differentiated OSCC, cells were diffused. Statistically significant difference in positive expression of Ki-67 was appreciated between three groups.

Conclusion

Ki-67 antigen may perhaps be used as a marker for the histological reviewing of OED and OSCC. With the increase in the severity of OED, cells showing positive expression of Ki-67 also increased.

A comparative study of osteopontin expression, Ki67 index and prognosis in squamous cell carcinoma and cysts of the oral cavity

Background

Recent studies have shown a strong relationship between the expression of osteopontin and oral carcinogenesis. Osteopontin (OPN) has been shown to play a major role in regulating the aggressiveness of cancer cells and promote tumor growth. Odontogenic cysts are an essential aspect of oral and maxillofacial pathology. They are relatively frequent lesions with different clinical behavior. Some of them may have a proliferative pattern of growth and neoplastic nature. Evaluation of osteopontin expression with Ki-67 index may help examine clinical behavior and recurrence of oral squamous cell cancer and radicular cyst patients.

Methods

A total of 44 oral cavity cancer cases and 21 cysts samples were analyzed by immunohistochemical staining. Data used for analysis were derived from medical records. The following information was obtained from all patients’ medical records: survival, age, sex, lymph node status, tumor size, and location, as well as grade and histologic type of tumor. Expression status of OPN and Ki-67 was statistically assessed.

Results

Our data demonstrated that for summary immunoreactive scores of OPN and Ki-67 expressions in OSCC vs. RC patients statistical significance was found for both markers’ between OSCC and RC groups. Moreover, osteopontin is significantly higher expressed in larger OSCC tumors.

Conclusions

In conclusion, the role of OPN expression both in oral squamous cancer cells and radicular cyst and possible correlation with demographic and clinicopathological features remain undetermined in some aspects, further high-powered studies to develop a more standardized assessment of Ki-67 and osteopontin expression in OSCC and are needed.

Evaluation of Ki-67 Expression in Oral Submucous Fibrosis and Its Correlation with Clinical and Histopathological Features

Objectives:

Oral submucous fibrosis (OSMF) is a potentially malignant disorder. Although it shows atrophic epithelium, it has a high proliferative capacity. Therefore, this study correlates the Ki-67. (The name “ki” is derived from the city of origin [Kiel, Germany] expression with functional grading and epithelial thickness in OSMF).

Methods:

The study group comprised of thirty patients of OSMF, divided randomly into Group A, Group B, Group C, and Group D as per mouth opening (functional staging). Five participants without OSMF formed the negative control group. The positive control group comprised of five patients of diagnosed cases of squamous cell carcinoma. All the sections of biopsy were subjected for hematoxylin and eosin and immunohistochemistry staining and observed for expression of Ki-67. Epithelial thickness was evaluated using image analysis software of Leica research microscope. Images were analyzed by three independent observers who were blindfolded. All the findings were tabulated and statistically analyzed.

Results:

In the present study, as the functional staging increased, the Ki-67 expression also increased. Ki-67 expression was highest in severe functional staging/severely decreased mouth opening (100.78) and is least in mild functional staging/mild decreased mouth opening (10.39). However, there was no significant correlation between epithelial thickness and functional staging/mouth opening (P > 0.05).

Conclusion:

A decrease in functional staging (mouth opening) showed a greater expression of Ki-67, and there was no significant correlation between functional staging and epithelial thickness.

Ki-67 Prognostic Value in Different Histological Grades of Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

Introduction:

Abnormal cell proliferation appears to be a possible predictor of tumorigenesis, Ki-67 protein expression is closely related to the cell proliferation and could be used as a biomarker for the growth in the most of human tumors. The aim of the study: Investigating of Ki-67 expression in the pathological grades of oral epithelial dysplasia and oral squamous cell carcinomas.

Materials and Methods:

The sample consisted of 30 formalin-fixed, paraffin-embedded specimens of oral epithelial dysplasia (OED), 30 other of oral squamous cell carcinomas (OSCC), and 10 normal oral epithelium (NOE) were conventionally stained with hematoxylin and eosin and immunohistochemically stained with Ki-67 monoclonal antibody.

Results:

Expression of Ki-67 was restricted to the basal layers in the normal oral epithelium whereas Ki-67 positive cells in oral epithelial dysplasia (OED) were located in the basal, suprabasal and spinous layers, Ki-67 expression was increased in high-risk cases. Ki-67 positive cells in well-differentiated (OSCC) were located mainly in the periphery of the tumor nests, in moderately-differentiated (OSCC) were located in both peripheral and part of a center of the tumor nests whereas it was diffused in most of the Poorly-differentiated (OSCC). Statistical analysis indicated a significant difference between the expression in (OED) and (NOE), (OSCC) and (NOE), and no differences between (OED) and (OSCC).

Conclusion:

This study has concluded that Ki-67 antigen could be used as a marker for the histological grading of OED and OSCC, Expression of Ki 67 increased according to the severity of oral epithelial dysplasia.

Prevention of oral carcinogenesis in rats by Dracaena cinnabari resin extracts

OBJECTIVES

In vivo study was performed to determine the chemopreventive efficacy of the DC resin methanol extract on a 4-nitroquinoline-1-oxide (4NQO) oral cancer animal model.

MATERIALS AND METHODS

This study involves administration of 4NQO solution for 8 weeks alone (cancer induction) or with Dracaena cinnabari (DC) extract at 100, 500, and 1000 mg/kg. DC extract administration started 1 week before exposure until 1 week after the carcinogen exposure was stopped. All rats were sacrificed after 22 weeks, and histological analysis was performed to assess any incidence of pathological changes. Immunohistochemical expressions of selected tumor marker antibodies were analyzed using an image analyzer computer system, and the expression of selected genes involved in apoptosis and proliferative mechanism related to oral cancer were evaluated using RT²-PCR.

RESULTS

The incidence of OSCC decreased with the administration of DC extract at 100, 500, and 1000 mg/kg compared to the induced cancer group. The developed tumor was also observed to be smaller when compared to the induced cancer group. The DC 1000 mg/kg group inhibits the expression of Cyclin D1, Ki-67, Bcl-2, and p53 proteins. It was observed that DC 1000 mg/kg induced apoptosis by upregulation of Bax and Casp3 genes and downregulation of Tp53, Bcl-2, Cox-2, Cyclin D1, and EGFR genes when compared to the induced cancer group.

CONCLUSIONS

The data indicated that systemic administration of the DC resin methanol extract has anticarcinogenic potency on oral carcinogenesis.

CLINICAL RELEVANCE

Chemoprevention with DC resin methanol extract may significantly reduce morbidity and possibly mortality from OSCC.

Expression of hMLH1 and hMSH2 proteins in ameloblastomas and tooth germs

BACKGROUND

Mismatch repair proteins (MMRPs) are a group of nuclear enzymes that participate in the repair of base mismatches that occur during DNA replication in all proliferating cells. The most studied MMRPs are hMSH2 and hMLH1, which are known to be highly expressed in normal tissues. A loss of MMRPs leads to the accumulation of DNA replication errors in proliferating cells. Ki-67 is a biomarker regarded to be the gold-standard tool for determining cell proliferation by immunohistochemical methods. The aim of this study was to investigate the immunohistochemical expression of hMLH1, hMSH2 and Ki-67 proteins in ameloblastomas and tooth germs, to contribute to the understanding of the development of this odontogenic neoplasm.

MATERIAL AND METHODS

Immunohistochemical assays to determine the presence of proteins hMSH2, hMLH1 and Ki-67 were performed in 80 ameloblastomas (40 solid and 40 unicystic) and five tooth germs.

RESULTS

Unicystic ameloblastomas showed higher MMRP expression (hMLH1: 62.5 ± 43.4; hMSH2: 83.3 ± 47.8) than did solid ameloblastomas (hMLH1: 59.4 ± 13.5; hMSH2: 75.8 ± 40.2). Additionally, the cell proliferation index assessed by Ki-67 was inversely proportional to the expression of MMRP. Comparison between tooth germs and ameloblastoma revealed significantly higher expression of hMLH1, hMSH2 and Ki-67 in tooth germs (p=0.02).

CONCLUSIONS

The differences of MMRP and Ki-67 immunoexpression between ameloblastomas and tooth germ suggest that alterations in the MMRP mechanisms could participate in the biological behavior of ameloblastomas.

Proliferative Index in Invasive Tumor Front of Oral Squamous Cell Carcinoma: A Potential Prognostic Indicator

AIM

The aim of the study was to evaluate the proliferative index (PI) at their invasive front of oral cancer and their association with Bryne's grades of oral squamous cell carcinoma (OSCC) and compare the PI with lymph node metastasis, site of involvement, and habits.

MATERIALS AND METHODS

The Ki-67 antigen expression was immunohistochemically evaluated in a total of 102 cases that included the histopathologically diagnosed archival specimens of OSCCs. They were subdivided by Bryne's histopathological grading into grade I (40 cases), grade II (32 cases), and grade III (30 cases). The nucleus with brown stain was considered positive. Cells were counted under 400× magnification. The proliferative activity thus determined was then expressed as a percentage of Ki-67 labeling index (Ki-67 LI) positive cells.

RESULTS

A stepwise increase in the mean Ki-67 LI was found from grade I to III squamous cell carcinoma, thus correlating with the histological grading. In addition, there was a higher PI seen in cases associated with metastatic lymph node, which concords with the higher biologic aggressiveness and poor prognosis of the lesion.

CONCLUSION

The present study shows a definitive correlation of Ki-67 antigen with the Bryne's histological grading, all the parameters of Bryne's grading for OSCC and lymph node status of the patient proving its association as an effective tool to grade the tumors and finally read the prognosis of the tumor.

CLINICAL SIGNIFICANCE

Cell proliferation is regarded as one of the most important biologic mechanisms in oncogenesis. The role of cell proliferation in tumor progression has been inferred in studies concerned with human cancer by comparing the PI of normal tissue, preneoplastic and neoplastic lesions. The Ki-67 antigen-labeled cells can prove to be an effective aid to grade the tumors. It might be possible to standardize and objectify tumor grading among pathology laboratories.

Anti-tumor effect of cisplatin in human oral squamous cell carcinoma was enhanced by andrographolide via upregulation of phospho-p53 in vitro and in vivo

Oral squamous cell carcinoma is one of the most common neoplasm in the world. Despite the improvements in diagnosis and treatment, the outcome is still poor now. Thus, the development of novel therapeuticapproaches is needed. The aim of this study is to assess the synergistic anti-tumor effect of andrographolide with cisplatin (DDP) in oral squamous cell carcinoma CAL-27 cells in vitro and in vivo. We performed Cell Counting Kit-8 proliferation assay, apoptosis assay, and western blotting on CAL-27 cells treated with andrographolide, DDP or the combination in vitro. In vivo, we also treated CAL-27 xenografts with andrographolide or the combination, and performed terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay and immunohistochemical analysis of Ki-67. The results showed the combination of andrographolide and DDP synergistically inhibited CAL-27 cell proliferation in vitro and caused tumor regression in vivo in the CAL-27 xenografts. In addition, the synergistic anti-tumor effect of andrographolide with synergistic was due to an enhanced apoptosis. Moreover, the combination therapy upregulated the expression level of p-p53 in vitro and decreased Ki-67 expression in vivo. Our data indicate that the combination treatment of andrographolide and DDP results in synergistic anti-tumor growth activity against oral squamous cell carcinoma CAL-27 in vitro and in vivo. These results demonstrated that combination of andrographolide with DDP was likely to represent a potential therapeutic strategy for oral squamous cell carcinoma.

Tumor markers: A diagnostic tool

The purpose of this review is to give a brief background to enable the judicious use of widely performed serum cancer markers. The markers could be product of cancerous cell or as response to cancer. They are usually proteins, which are mainly found in blood or urine. These markers may be employed to predict primary or secondary tumor risk. Sometimes, non-cancerous conditions can also cause elevation of some tumor markers to be higher than normal. Besides, not every cancer patient may have raised level of a tumor marker. For these reasons, knowledge about cancer biomarkers has increased tremendously. Awareness for cancer and related tumor markers providing great opportunities for improving the management of cancer patients by enhancing the efficiency of detection and efficacy of treatment.

Immunohistochemical expression of matrix metalloproteinase-1, matrix metalloproteinase-2 and matrix metalloproteinase-9, myofibroblasts and Ki-67 in actinic cheilitis and lip squamous cell carcinoma

Matrix metalloproteinases (MMPs), myofibroblasts (MFs) and epithelial proliferation have key roles in neoplastic progression. In this study immunoexpression of MMP-1, MMP-2 and MMP-9, presence of MFs and the epithelial proliferation index were investigated in actinic cheilitis (AC), lip squamous cell carcinoma (LSCC) and mucocele (MUC). Thirty cases of AC, thirty cases of LSCC and twenty cases of MUC were selected for immunohistochemical investigation of the proteins MMP-1, MMP-2, MMP-9, α-smooth muscle actin (α-SMA) and Ki-67. The MMP-1 expression in the epithelial component was higher in the AC than the MUC and LSCC. In the connective tissue, the expression was higher in the LSCC. MMP-2 showed lower epithelial and stromal immunostaining in the LSCC when compared to the AC and MUC. The epithelial staining for MMP-9 was higher in the AC when compared to the LSCC. However, in the connective tissue, the expression was lower in the AC compared to other lesions. The cell proliferation rate was increased in proportion to the severity of dysplasia in the AC, while in the LSCC it was higher in well-differentiated lesions compared to moderately differentiated. There were no statistically significant differences in number of MFs present in the lesions studied. The results suggest that MMPs could affect the biological behaviour of ACs and LSCCs inasmuch as they could participate in the development and progression from premalignant lesions to malignant lesions.

Efficacy of quercetin against chemically induced murine oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common form of head and neck cancer, and oxidative damage is associated with the development of OSCCs. Antioxidants have therefore been proposed for use as chemoprotective agents against different types of cancer. In the present study, the effect of the antioxidant quercetin, administered at doses of 10 and 100 mg/kg/day, was investigated in an experimental murine model of 4-nitroquinoline 1-oxide (4-NQO)-induced carcinogenesis. The survival of the treated animals, the plasmatic levels of reduced glutathione and the type and severity of lesions (according the International Histological Classification of Tumors and Bryne's Multifactorial Grading System for the Invasive Tumor Front) were assessed. Additionally, the organization of the extracellular matrix was analyzed by carbohydrate and collagen histochemistry, and immunohistochemistry was used to assess the expression of the tumor markers proliferating cell nuclear antigen and mutated p53. The results indicate that, despite the promising effect of quercetin in other studies, this drug is ineffective as a chemoprotective agent against 4-NQO-induced OSCC in mice at the assayed doses.

Immunoexpression of Ki-67, MCM2, and MCM3 in Ameloblastoma and Ameloblastic Carcinoma and Their Correlations with Clinical and Histopathological Patterns

Cell proliferation assays are performed using antibodies against nuclear proteins associated with DNA replication. These nuclear proteins have gained special interest to predict the biological and clinical behaviors of various tumors. The aim of this study was to analyze the presence of Ki-67 protein and the minichromosome maintenance-2 (MCM2) and maintenance-3 (MCM3) proteins in ameloblastoma. Materials and Methods. Cell proliferation marker expression levels were assessed via immunohistochemistry in 111 ameloblastoma cases (72 unicystic ameloblastoma samples, 38 solid/multicystic ameloblastoma samples, and 1 ameloblastic carcinoma). The label index was performed as described previously. Results. MCM2 and MCM3 showed higher proliferation indexes in all variants of ameloblastoma compared to the classic marker Ki-67. No correlation between the proliferation index and the clinical and protein expression data was observed. Conclusion. The results suggest that clinical features do not directly affect tumor cell proliferation. Moreover, the high levels of cellular proliferation of MCM2 and MCM3 compared with Ki-67 may indicate that MCM2 and MCM3 are more sensitive markers for predicting the growth rate and eventually might be helpful as a tool for predicting aggressive and recurrent behaviors in these tumors.

Expression of Ki-67 in normal oral epithelium, leukoplakic oral epithelium and oral squamous cell carcinoma

Aims and Objective:

To demonstrate the presence, location and pattern of cell proliferation in different histological grades of oral epithelial dysplasia (OED), oral squamous cell carcinoma (OSCC) and normal oral epithelium (NOE) using an antibody directed against the Ki-67 antigen and its intensity of staining evaluated respectively.

Materials and Methods:

A total number of 100 archival paraffin embedded blocks obtained from Department of Oral and Maxillofacial Pathology were studied. The case details were retrieved which consisted of histopathologically diagnosed cases of OSCC (n = 20), low risk OED (n = 30), high risk OED (n = 30) and normal appearing mucosa (n = 20) were taken as standard for comparison. Ki-67 immunostaining was detected. Ki-67 positive cells were counted in the five random high power fields in each case.

Results:

Ki-67 labeling Index (LI) was restricted to the basal and parabasal layers of the normal oral epithelium irrespective of age, sex and site whereas it was seen in the basal, suprabasal and spinous layers in OED. Ki-67 LI is increased in high risk cases than the low risk cases of OED. Ki-67 positive cells in OSCC were located in the periphery of the tumor nests than the center, where frequent mitoses were observed.

Conclusion:

The architectural alteration evaluated by Ki-67 antibody in proliferating cell distribution in the layers of epithelial dysplasias may provide useful information to evaluate the grading of OED. Ki-67 LI increased in high risk cases than low risk cases of OED. This study showed that over expression of Ki-67 antigen between well-differentiated and poorly differentiated OSCC was in accordance with histologic grade of malignancy but not in accordance with moderately differentiated OSCC.

Immunohistochemical analysis of Ki-67 in dental follicle of asymptomatic impacted third molars

INTRODUCTION

Dental follicle (DF) is an ectomesenchymal tissue that surrounds the developing tooth germ and contains precursor cells for cementoblasts, periodontal ligaments and osteoblasts. Radiographically, the DFs are seen as semicircular radiolucencies around unerupted teeth. However, if the DFs are larger than 2.5 mm, they are considered to be a pathological change.

AIMS AND OBJECTIVES

The purpose of this study is to assess the cell proliferation activity of DF surrounding an asymptomatic impacted third molar teeth using the Ki 67 proliferation marker and to evaluate the variation of cell proliferation depending on the age factor.

MATERIALS AND METHODS

Forty-four specimens of DFs associated with impacted mandibular third molars fully covered by mucosa or bone were surgically removed from 44 patients. The patients were divided into 2 age groups. Twenty of forty-four DFs were between 18 and 29 years (Group 1) and 24 were 30 years and above (Group 2). Ki-67 immunostaining was evaluated in epithelial component of the DFs.

RESULTS

Ki 67 expression was found to be 60% in Group 1 and 75% in Group 2. Statistically significant differences were found among the two groups in both the basal layer and the supra-basal layer.

CONCLUSION

This study shows that DFs have more proliferative potential in older people as compared to the young and squamous metaplasia may be an early sign of developing lesions of odontogenic origin. Therefore, clinicians should be aware that histopathological changes could be found in DFs without clinical and radiographic alterations.

Histological and molecular aspects of oral squamous cell carcinoma (Review)

Oral squamous cell carcinoma (OSCC) represents 95% of all forms of head and neck cancer, and over the last decade its incidence has increased by 50%. Oral carcinogenesis is a multistage process, which simultaneously involves precancerous lesions, invasion and metastasis. Degradation of the cell cycle and the proliferation of malignant cells results in the loss of control mechanisms that ensure the normal function of tissues. The aim of the current review is to present the histopathological features of OSCC, including potentially malignant changes, the international classification of tumors, the tumor invasion front and tumor biomarkers (Ki-67, p53, homeobox genes and collagen type IV), as well as the tumor microenvironment and function of cancer-associated fibroblasts in the most common type of oral cancer that is encountered by dental surgeons. In OSCC, associations have been identified between the proliferation, basal lamina degradation and connective tissue modulation. Therefore, the comparison of these factors with the survival time of OSCC patients from the histopathological diagnosis is of interest.

[Significance of epithelial-mesenchaymal transition phenotype in invasive tumor front cells of lung squamous cell carcinoma]

背景与目的

肿瘤浸润前沿（invasive tumor front, ITF）细胞是指肿瘤与宿主组织交界处的细胞或浸润的细胞团，对判断患者预后具有较高的价值。本研究旨在探讨肺鳞状细胞癌（squamous cell carcinoma, SCC）ITF细胞的上皮-间叶转化（epithelial-mesenchaymal transition, EMT）表型特点，并分析与临床病理特征和预后的关系。

方法

采用免疫组织化学SP法检测104例肺SCC ITF细胞中上皮性标志物E-cadherin/β-catenin和间叶性标志物vimentin的表达。

结果

E-cadherin在53.8%（56/104）的肺SCC ITF细胞中表达下调，较非ITF细胞表达降低（P=0.04），而vimentin在42.3%（44 /104）ITF细胞中表达，较非ITF肿瘤细胞表达升高；两者均与肿瘤浸润方式、肺门淋巴结转移和患者预后有相关性（P < 0.01）。β-catenin在肺SCC ITF细胞的表达阳性率为67.3%（70/104），低于非ITF细胞（P < 0.01），在ITF细胞呈胞质和胞核阳性表达，并与肺门淋巴结转移密切相关。

结论

肺SCC ITF细胞中E-cadherin/β-catenin表达缺失和vimentin高表达可能与患者的不良预后有关。

Suprabasal expression of Ki-67 as a marker for the severity of oral epithelial dysplasia and oral squamous cell carcinoma

Background:

Transition of the normal oral epithelium to dysplasia and to malignancy is featured by increased cell proliferation. To evaluate the hypothesis of distributional disturbances in proliferating and stem cells in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC).

Aim:

To evaluate layer wise expression of Ki-67 in oral epithelial dysplasia and in OSCC.

Materials and Methods:

Thirty histologically confirmed cases of oral epithelial dysplasia, fifteen cases of OSCC and five cases of normal buccal mucosa were immunohistochemically examined and nuclear expression of Ki-67 was counted according to basal, parabasal, and suprabasal layers in epithelial dysplasia and number of positive cells per 100 cells in OSCC as labeling index (LI).

Results:

Suprabasal expression of Ki-67 increased according to the severity of epithelial dysplasia and the difference was statistically significant (P < 0.001). The mean Ki-67LI was 12.78 for low risk lesions, 28.68 for high risk lesions, 39.45 for OSCC and 13.6 for normal buccal mucosa.

Conclusion:

The results of the present study demonstrate the use of proliferative marker Ki-67 in assessing the severity of epithelial dysplasia. Suprabasal expression of Ki-67 provides an objective criteria for determining the severity of epithelial dysplasia and histological grading of OSCC.

Assessment of cellular proliferation in oral verrucous carcinoma and well-differentiated oral squamous cell carcinoma using Ki67: a non-reliable factor for differential diagnosis?

BACKGROUND

Non-invasive oral verrucous carcinoma (OVC) and invasive well-differentiated oral squamous cell carcinoma (OSCC) have similar histopathologic findings but different biological behavior. These two malignancies must be correctly differentiated by pathologists. The aim of this study was to determine immunohistochemical (IHC) expression of Ki67 in OVC and well-differentiated OSCC.

METHODS

Expression of Ki67 was evaluated by IHC in 15 cases of epithelial hyperplasia with no dysplasia (A group), 15 cases of OVC (B group), 12 cases of microinvasive OSCC(C group) and 15 cases of well-differentiated OSCC (D group).

RESULTS

There was a significant difference in Ki67 expression based on pattern distribution of immunostaining positive cells, with quantitative and semi-quantitative analyses, among the four groups ; also, between A group and each of the other three groups (P=0.0001). But there was no significant difference between B and C, C and D, and B and D groups (P>0.05).

CONCLUSIONS

The three evaluation methods of Ki67 expression showed Ki67 (Mib-1) is not a good immunohistochemical marker to assess invasion status and differentiate OVC from well-differentiated OSCC; also, it cannot be used as a diagnostic tool to distinguish between variants of OSCC with similar grade.

Comparison of the value of PCNA and Ki-67 as markers of cell proliferation in ameloblastic tumors

OBJECTIVES

The aim of this study was to compare among PCNAand Ki-67 as the most reliable immunohistochemical marker for evaluating cell proliferation in ameloblastic tumors.

STUDY DESIGN

Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, composed of 161 ameloblastomas and four ameloblastic carcinomas, to determine and compare PCNA and Ki-67 expression using immunohistochemistry techniques.

RESULTS

When analyzing Ki-67 positivity, the desmoplastic ameloblastoma demonstrated a significantly lower proliferation rate (1.9%) compared with the solid/multicystic and unicystic ameloblastomas and ameloblastic carcinomas (p<0.05), whereas the ameloblastic carcinomas displayed a significantly higher rate compared with all of the other ameloblastomas (48.7%) (p<0.05). When analyzing cell proliferation with PCNA, we found significant differences only between the ameloblastic carcinomas (93.3%) and the desmoplastic ameloblastomas (p<0.05). When differences between the immunopositivity for PCNA and Ki-67 were compared, the percentages were higher for PCNA in all types of ameloblastomas and ameloblastic carcinomas. In all cases, the percentages were greater than 80%, whereas the immunopositivity for Ki-67 was significantly lower; for example, the ameloblastic carcinoma expressed the highest positivity and only reached 48.7%, compared to 93.3% when we used PCNA.

CONCLUSIONS

In the present study, when we used the proliferation cell marker Ki-67, the percentages of positivity were more specific and varied among the different types of ameloblastomas, suggesting that Ki-67 is a more specific marker for the proliferation of ameloblastic tumor cells.

Immunohistochemical comparative analysis of cell proliferation and angiogenic index in squamous cell carcinomas of the tongue between young and older patients

Oral squamous cell carcinoma (SCC) is a malignant epithelial tumor that is uncommon in individuals younger than 45 years. This study compared the cell proliferation and angiogenic index in SCCs of the tongue between young and older patients. Forty SCCs of the tongue, 20 diagnosed in young patients (≤ 40 y) and 20 diagnosed in older patients (>50 y) were evaluated by immunohistochemistry. Cell proliferation was evaluated using the Ki-67 labeling index (LI). The angiogenic index was determined by microvessel count (MVC) using anti- von Willebrand factor antibody. The mean Ki-67 LI in SCCs of the tongue was 43.8% (range, 26.0% to 72.4%) in young patients and 42.5% (range, 9.0% to 59.4%) in older patients (P=0.968). No significant difference in the Ki-67 LI was observed in relation to clinical stage or histologic grade of malignancy in either group (P>0.05). The mean MVC in SCCs of the tongue was 24.3 (range, 8.6 to 51.6) in young patients and 25.6 (range, 5.4 to 42.4) in older patients (P=0.543). There was no significant difference in MVC in relation to clinical stage or histologic grade of malignancy in either group (P>0.05). In addition, no significant correlation was observed between the Ki-67 LI and the angiogenic index (P>0.05). The results of this study suggest that the more aggressive biological behavior of SCC of the tongue in young patients may not be related to a higher cell proliferation rate or a higher angiogenic index.

Cortactin is associated with perineural invasion in the deep invasive front area of laryngeal carcinomas

The cortactin gene, mapped at 11q13, has been associated with an aggressive clinical course in many cancers because of its function of invasiveness. This study evaluated CTTN protein and its prognostic value in the deep invasive front and superficial areas of laryngeal squamous cell carcinomas. The transcript expression levels were evaluated in a subset of cases. Overexpression of CTTN cytoplasmatic protein (80% of cases in both the deep invasive front and superficial areas) and transcript (30% of samples) was detected in a significant number of cases. In more than 20% of cases, observation verified membrane immunostaining in the deep invasive front and superficial areas. Perineural invasion was significantly associated with N stage and recurrence (P = .0058 and P = .0037, respectively). Higher protein expression levels were correlated with perineural invasion (P = .004) in deep invasive front cells, suggesting that this area should be considered a prognostic tool in laryngeal carcinomas. Although most cases had moderate to strong CTTN expression on the tumor surface, 2 sets of cases revealed a differential expression pattern in the deep invasive front. A group of cases with absent to weak expression of CTTN in the deep invasive front showed good prognosis parameters, and a second group with moderate to strong expression of CTTN were associated with an unfavorable prognosis, suggesting an association with worse outcome. Taken together, these results suggest that the deep invasive front might be considered a grading system in laryngeal carcinomas and that cortactin is a putative marker of worse outcome in the deep invasive front of laryngeal carcinomas.

Chronic restraint stress in oral squamous cell carcinoma

Pathogenic processes have been identified that could associate chronic stress and cancer, but these findings have not been observed in oral cancer. This study examined the role of chronic restraint stress on the incidence and severity of OSCC induced with 4-nitroquinoline-1-oxide (4-NQO) in the tongues of CF-1 mice. One hundred twenty CF-1 male mice were divided into 4 groups: (A) received two treatments - restraint stress and induction of chemical carcinogenesis (n = 50); (B) induction of chemical carcinogenesis, without restraint stress (n = 50); (C) restraint stress (n = 10); and (D) control (n = 10). After 30 weeks, tongues were dissected and analyzed by conventional histopathology. The severity of OSSC was analyzed according to the International Histological Classification of Tumors and Bryne's Multifactorial Grading System for the Invasive Tumor Front (ITF). Chronic stress induction was confirmed by plasma corticosterone levels. Results showed that chronic stress was induced with movement restriction (p ≤ 0.05, Mann-Whitney U-test). However, chronic stress did not increase the incidence (p > 0.05, Chi-square) or severity (p > 0.05, Mann-Whitney U-test) of the 4-NQO-induced OSSC in the tongues of CF-1 mice. These results suggest that there is no relationship between chronic stress (induced in mice by restraint) and the incidence and severity of OSSC.

Proliferative activity and diagnostic delay in oral cancer

BACKGROUND

Tumor stage may relate to the chronology of neoplasm growth and has been used as an outcome variable when studying diagnostic delay in oral cancer. However, tumor growth rate may act as a confounding factor.

METHODS

We reviewed a total of 63 incident cases of oral cancer. The variables considered for the study included age, sex, smoking history, tumor site, TNM stage, Ki-67 score, and diagnostic delay.

RESULTS

Significant differences between survivors and exitus were found in terms of tumor stage at diagnosis (I-II vs III-IV), sex, and Ki-67 scores. When the analysis was adjusted for tumor stage at diagnosis (I-II vs III-IV), proliferative activity resulted to be an independent prognostic factor for survival, whereas diagnostic delay did not influence survival.

CONCLUSION

These results seem to suggest that survival from oral cancer is affected more by the biology of the cancer (rapid tumor growth) than by diagnostic delay.

Abnormal cell-cycle expression of the proteins p27, mdm2 and cathepsin B in oral squamous-cell carcinoma infected with human papillomavirus

Since the role of human papillomavirus (HPV) infection in oral carcinogenesis is still unclear, the purpose of this study was to verify the association between the expression of p27, mdm2 and cathepsin B and by HPV-related oral lesions. Fifty-five oral biopsies were studied and HPV detection and typing (6/11, 16, 18, 31 and 33) were performed using polymerase chain reaction techniques. The distribution p27, mdm2 and cathepsin B was determined by immunohistochemistry. Twenty-one (38%) out of the 55 oral lesions tested positive for HPV, of which 6 (33%) were HPV 6/11, 1 (5%) was HPV 16, 14 (72%) were HPV 18 and none was HPV 33/31. Among the 55 biopsies, immunopositivity for p27, mdm2 and cathepsin B was observed in 17 (30.9%), 37 (67.2%) and 37 (67.2%), respectively. Among 21 HPV-positive oral lesions, immunopositivity of mdm2, p27 and cathepsin B was found, respectively, in 6 (33%) out of 18 benign lesions (BL), 4 (22%) out of 18 potential malignant epithelial lesions (PMEL) and 11 (57.9%) out of 19 malignant lesions (ML). High-risk HPV types may be associated with oral carcinoma, by cell-cycle control dysregulation, contributing to oral carcinogenesis and the overexpression of mdm2, p27 and cathepsin B.

Oral squamous cell carcinoma versus oral verrucous carcinoma: an approach to cellular proliferation and negative relation to human papillomavirus (HPV)

Human papillomavirus (HPV) has been cited as a possible initiating agent in the pathogenesis of oral cancer. However, the literature tends to be both controversial and inconclusive about the prevalence of HPV and its potential for proliferation in oral squamous cell carcinoma (SCC). The aim of this study was to investigate the cellular proliferation and the presence of HPV in SCC and verrucous carcinoma (VC). Forty-seven samples of SCC were selected and divided into three groups: 39 SCC, 8 VC, and 9 of normal mucosa (control-CT). Quantitative analyses of all groups showed a greater expression of PCNA, followed by Ki-67 and cyclin B1. A significant difference was observed in cyclin B1 expression in the SCC group compared with VC. PCNA, Ki-67, and cyclin B1 were statistically significant when comparing the SCC and CT groups. However, when SCC and VC were compared, there was no difference in Ki-67 expression. Our results showed that only cyclin B1 had an association with histological grade, and that poorly differentiated tumors presented a higher expression of cyclin B1. Therefore, considerable differences in the cellular proliferation between SCC and VC were observed, and no correlation with HPV was established, since all samples were negative for HPV.

VILIP-1 expression in vivo results in decreased mouse skin keratinocyte proliferation and tumor development

VILIP-1, a member of the neuronal Ca²⁺ sensor protein family, is able to act as a tumor suppressor in carcinoma cells by inhibiting cell proliferation and migration. In order to study the role of VILIP-1 in skin carcinogenesis we generated transgenic mice overexpressing VILIP-1 in epidermis under the control of the bovine keratin K5 promoter (K5-VILIP-1). We studied the susceptibility of FVB wild type and VILIP-1 transgenic mice to chemically mediated carcinogenesis. After 30 weeks of treatment with a two-stage carcinogenesis protocol, all animals showed numerous skin tumors. Nevertheless, K5-VILIP-1 mice showed decreased squamous cell carcinoma (SCC) multiplicity of ∼49% (p<0.02) with respect to the corresponding SCC multiplicity observed in wild type (WT) mice. In addition, the relative percentage of low-grade cutaneous SCCs grade I (defined by the differentiation pattern according to the Broders grading scale) increased approximately 50% in the K5-VILIP1 mice when compared with SCCs in WT mice. Similar tendency was observed using a complete carcinogenesis protocol for skin carcinogenesis using benzo(a)pyrene (B(a)P). Further studies of tumors and primary epidermal keratinocyte cultures showed that matrix metalloproteinase 9 (MMP-9) levels and cell proliferation decreased in K5-VILIP-1 mice when compared with their wild counterparts. In addition tissue inhibitor of metalloproteinase 1 (TIMP-1) expression was higher in K5-VILIP-1 keratinocytes. These results show that VILIP-1 overexpression decreases the susceptibility to skin carcinogenesis in experimental mouse cancer models, thus supporting its role as a tumor suppressor gene.

Reproducibility of immunostaining quantification and description of a new digital image processing procedure for quantitative evaluation of immunohistochemistry in pathology

Quantification of immunostaining is a widely used technique in pathology. Nonetheless, techniques that rely on human vision are prone to inter- and intraobserver variability, and they are tedious and time consuming. Digital image analysis (DIA), now available in a variety of platforms, improves quantification performance: however, the stability of these different DIA systems is largely unknown. Here, we describe a method to measure the reproducibility of DIA systems. In addition, we describe a new image-processing strategy for quantitative evaluation of immunostained tissue sections using DAB/hematoxylin-stained slides. This approach is based on image subtraction, using a blue low pass filter in the optical train, followed by digital contrast and brightness enhancement. Results showed that our DIA system yields stable counts, and that this method can be used to evaluate the performance of DIA systems. The new image-processing approach creates an image that aids both human visual observation and DIA systems in assessing immunostained slides, delivers a quantitative performance similar to that of bright field imaging, gives thresholds with smaller ranges, and allows the segmentation of strongly immunostained areas, all resulting in a higher probability of representing specific staining. We believe that our approach offers important advantages to immunostaining quantification in pathology.

Predictive Role of p53 Protein as a Single Marker or Associated to Ki67 Antigen in Oral Carcinogenesis

p53 over-expression has been proposed as a reliable marker associated to oral carcinogenesis, although only about 50% of oral carcinomas (OSCC) are associated with p53 over-expression and even p53-negative lesions can progress to OSCC. The aim of the study was to determine whether the combination of p53 over-expression and p53 low-expression associated with Ki67 over-expression (high Ki67/p53 ratio) could lead to a more sensitive parameter. Immunohistochemical expression of Ki67 and p53 was measured in 54 specimens from OSCC; 27 specimens from moderate/severe epithelial dysplasia; 32 specimens from oral leukoplakias without epithelial dysplasia, and 13 specimens with normal epithelium. p53 over-expression was found in 31 (53%) samples from OSCC, in 10 (37%) samples from severe dysplasias, and in 5 (15%) samples from non-dysplastic lesions, while the combination of high p53 values with high Ki67/p53 ratio was observed in 93% of OSCC, in 81% of dysplastic lesions, and in 50% of non-dysplastic lesions. This parameter may have a clinical implication to detect early lesions with an impairment of p53 pathway, and probably at risk of progress to 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.

Molecular markers of head and neck squamous cell carcinoma: promising signs in need of prospective evaluation

BACKGROUND

The aim of this article is to review recent developments in the biological understanding of head and neck squamous cell carcinomas.

METHODS AND RESULTS

We describe the markers according to their function and their prognostic or predictive roles. Some associations can be found between molecular markers and invasiveness, aggressiveness, degree of differentiation, and tumor stage, but only a few clinical studies have shown an impact on prognosis. In addition, despite an increasing number of articles relating to this topic, the small number of patients included in the studies reported reduces the clinical implications of these results. Few studies applied a more comprehensive molecular analysis approach, such as DNA microarrays or differential expression profiling by polymerase chain reaction, to identify a combination of markers that could be more informative than a single molecular marker.

CONCLUSION

Some progress has been made with respect to molecular markers and head and neck cancers. Translational and prospective, hypothesis-driven research must proceed with sufficient rigor to facilitate the clinical applicability of such results.

Reduced syndecan-1 expression is correlated with the histological grade of malignancy at the deep invasive front in oral squamous cell carcinoma

BACKGROUND

Although many histopathological characteristics of oral squamous cell carcinoma (O-SCC) have been identified as prognostic factors, no factor is completely accurate and unequivocal. This study evaluated the association between the loss of syndecan-1 expression and the histological grade of malignancy at the deep invasive front in O-SCC.

METHODS

The expression of syndecan-1 at the invasive tumor front of O-SCC was examined immunohistochemically using archived tissue from 72 cases. The mean age of the patients was 62.5 years (range: 23-90 years) and the male-female ratio was 1.3:1 (41 men, 31 women). There were 26, 24, 11, and 11 cases classified as stages I-IV respectively. The correlation between the intensity of syndecan-1 immunostaining and the clinicopathological factors, especially the histological grade of malignancy at the deep invasive front (invasive front grade) was analyzed.

RESULTS

Of the 72 cases, seven (9.7%), 29 (40.3%), 36 (50.0%) showed strong, intermediate, and weak or negative syndecan-1 staining respectively. There were significant differences between syndecan-1 expression and prognosis, differentiation, and pattern of invasion at the deep invasive front. Moreover, the invasive front grade scores, based on the intensity of syndecan-1 staining, were 5.6 +/- 1.0, 8.0 +/- 2.1, and 10.2 +/- 2.3 points with strong, intermediate, and weak or negative intensity respectively; and the difference was significant (P < 0.0001). Patients with intermediate or strong intensity for syndecan-1 had significantly better prognoses than did those with negative or weak intensity (P = 0.0138).

CONCLUSION

This study demonstrated that the reduced expression of syndecan-1 seems to be a useful marker of histological malignancy at the deep tumor invasive front and may be a useful prognostic factor in O-SCC.

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.

The relationship of the histologic grade at the deep invasive front and the expression of Ki-67 antigen and p53 protein in oral squamous cell carcinoma

BACKGROUND

Although many histopathologic characteristics of oral squamous cell carcinoma (O-SCC) have been identified as prognostic factors, accurate, and unequivocal factors have not been clearly identified. The purpose of this study was to evaluate a potential association between the histologic grade of malignancy at the deep invasive front and the expression of Ki-67 antigen and p53 protein in O-SCC.

METHODS

The expression of Ki-67 antigen and p53 at the invasive tumor front area of O-SCC was examined by immunohistochemistry of archived tissue from 62 cases. The mean age of patients was 60.7 years (range: 37-89) and the male-female ratio was 1.6:1 (38 men, 24 women). There were 20, 17, 14, and 11 cases classified as stage I to stage IV, respectively. The correlation between the intensity of immunostaining for Ki-67 antigen and p53 and the histologic grade of malignancy at the deep invasive front (invasive front grade, IFG) was analyzed. The expression of Ki-67 antigen and p53 in normal oral epithelia (10 cases) was also investigated.

RESULTS

The mean Ki-67 labeling index (LI) in the O-SCC samples was 32.8 +/- 12.0% (n = 62). The mean total score of IFG (IFG score) was 9.1 +/- 2.7 points (n = 62). There was a significant linear correlation between the IFG score and the Ki-67 antigen (gamma = 0.651, R2 = 0.596, P < 0.0001). Of 50 tumors examined, 27 (54.0%) exhibited p53-positive nuclear immunostaining. The staining patterns for Ki-67 antigen and p53 were similar. Both Ki-67-LI and p53-positive status were significantly correlated with the IFG scores.

CONCLUSION

The findings of this study demonstrate that overexpression of Ki-67 antigen and p53 at the deep tumor invasive front of O-SCC is associated with histologic grade of malignancy.

Comparison of cell proliferation in the centre and advancing fronts of oral squamous cell carcinomas using Ki-67 index

The cell proliferation status of 60 oral squamous cell carcinomas from Sri Lankan subjects was examined by immunohistochemistry using the Ki-67 index. A comparison was made between the indices derived from the centre of the tumours and those derived from the invasive fronts of the same tumours. There was a positive correlation between the two indices suggesting a clonal expansion of malignant cells, but the mean index derived for the invasive fronts (29.75 11.64) was significantly higher than the mean index for the body of these tumours (25.65 11.64). Thus, at a given time, more peripheral cells at the invasive front are proliferating and this compartment is likely to be more informative in prognostic and other behavioural studies involving the cell cycle. In squamous carcinomas, increased and uncontrolled cell proliferation at the invasive front may be one feature contributory to the invasion.