Co-expression of Ki-67 and p53 protein in ameloblastoma and keratocystic odontogenic tumor

Abstract

Objectives. The purpose of this study was to evaluate the cell proliferation and p53 protein expression in ameloblastomas (ABs), keratocystic odontogenic tumor (KCOT) and dentigerous cyst (DC). Method. The immunohistochemistry were carried out for Ki-67 and p53 protein expression by using MIB-1 clone and DO-7 clone, respectively, in ABs (n = 23), KCOT (n = 32), DC (n = 30), normal oral mucosa (NOM) (n = 12) and fetal oral mucosa (FOM) (n = 10). Results. Both the Ki-67 LI Labeling index (LI) and p53 LI was significantly higher in ABs than KCOT, DC, NOM and FOM. The Ki-67 LI and p53 LI was significantly higher in KCOT as compared to DC. Ki-67 LI and p53 LI was observed in descending order in ABs, KOCT, FOM, NOM and DC. There was significant correlation between Ki-67 expression and p53 expression in ABs, KCOT, DC and NOM. The densely stained p53 positive cells were noted higher in ABs than KCOT. The very few densely p53 positive cells were noted in DC, NOM and FOM. Conclusion. The results suggest that the p53 protein expression does not necessarily imply an association with malignant disease and/or p53 gene mutation, but a tendency to be expressed in an increasing quantitative and qualitative manner, as the biologic behavior of odontogenic cyst or tumors becomes more aggressive. p53 over-expression may promote cell proliferation in odontogenic lesions. Thus, it can be stipulated that Ki-67 and p53 protein expression can be used as a prognostic marker in odontogenic lesions.     

Cell proliferation, apoptosis and apoptosis-related factors in odontogenic keratocysts and in dentigerous cysts

BACKGROUND: The purpose of this study was to elucidate why odontogenic keratocysts (OKC) can form cystic lesions but not tumor masses, notwithstanding their prominent proliferative activity. METHODS: We investigated cellular proliferation, cell death, and expression of apoptosis-related proteins in the lining cells of OKCs and of dentigerous cysts (DGCs). RESULTS: TdT-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells were observed in the surface layers of OKCs and of DGCs. However, no TUNEL-positive cells were seen in the basal or intermediate layers of both cysts. Ki67-positive ratio in the intermediate layer was the highest in OKCs. The p53-positive ratio of the intermediate layer was highest in OKCs. Bcl-2-positive cells were discernible exclusively in the basal layer of OKCs. CONCLUSIONS: These results suggest that cellular proliferation and death is regulated in association with apoptosis-related proteins in the lining epithelia of OKCs, and subsequently those cysts are seen as cystic lesions but not as tumor masses.     

p53 protein and Ki-67 reactivity in epithelial odontogenic lesions. An immunohistochemical study

Forty-five examples of epithelial odontogenic lesions (9 ameloblastomas (AB): 13 odontogenic keratocysts (OKC): 15 dentigerous cysts (DC): 6 radicular cysts (RC): and 2 odontogenic carcinomas (OC)) were immunohistochemically analyzed for the presence of p53 protein (p53P) and proliferative activity as indicated by positivity for Ki-67 antigen. p53P⁺ cells, detected as dense and/or faint nuclear staining, were found in 42 of the 45 odontogenic lesions examined. Dense p53P reactivity was most commonly detected in OKC, AB and OC, with other lesions generally exhibiting only weak nuclear reactivity. Numbers of Ki-67 positive cells as well as p53P⁺ cells were scored semiquantitatively. Although the presence/absence of densely stained p53P⁺ cells was broadly related to Ki-67⁺ cell numbers, there were no differences in p53P⁺ cell numbers between lesions exhibiting differences in proliferative activity. These results suggest that overexpression of p53P, rather than increased numbers of p53P⁺ cells, is related to proliferation in odontogenic epithelial lesions.     

Actual Proliferating Index and p53 protein expression as prognostic marker in odontogenic cysts

Background:  The purpose of this study was to evaluate the biological aggressiveness of odontogenic keratocyst/keratocystic odontogenic tumour (KCOT), radicular cyst (RC) and dentigerous cyst (DC) by observing the actual proliferative activity of epithelium, and p53 protein expression.
Methods:  The actual proliferative activity was measured by Ki-67 Labelling Index and argyrophilic nucleolar organizing regions (AgNOR) count per nucleus. The p53 protein expression was also evaluated.
Results:  Ki-67 positive cells were observed higher in suprabasal cell layers of KCOT with uniform distribution, a few of them were predominantly observed in basal cell layer in RC and DC. The AgNOR count was significantly higher in suprabasal cell layers of KCOT. The actual proliferative activity was noted to be higher in suprabasal cell layers of KCOT. The p53 immunolabelling was dense and scattered in basal and suprabasal cell layers in KCOT. The weakly stained p53 positive cells were observed diffusely distributed in KCOT, whereas they were mainly seen in basal cell layer of RC and DC.
Conclusion:  The quantitative and qualitative differences of the proliferative activity and the p53 protein expression in sporadic KCOT may be associated with intrinsic growth potential that could play a role in its development and explain locally aggressive biological behaviour. AgNOR count and p53 protein detection in odontogenic lesions can be of great consequence to predict the biological behaviour and prognosis.     

Immunohistochemical study of syndecan-1 down-regulation and the expression of p53 protein or Ki-67 antigen in oral leukoplakia with or without epithelial dysplasia

BACKGROUND: Leukoplakia is an oral pre-cancerous lesion that sometimes develops into squamous cell carcinoma. Therefore, leukoplakia with epithelial dysplasia is useful for studying carcinogenesis at the cellular level. The purpose of this study was to evaluate a potential association between the loss of syndecan-1 expression and the expression of p53 protein and Ki-67 antigen, and to identify reliable markers for predicting malignant changes in oral leukoplakia with epithelial dysplasia. METHODS: Changes in the expression of syndecan-1, p53, and Ki-67 were examined immunohistochemically in 43 cases of oral leukoplakia with or without epithelial dysplasia. The subjects were categorized as: none, 13 cases; mild dysplasia, 5 cases; moderate dysplasia, 17 cases; and severe dysplasia, 8 cases. The expression of these molecules in normal oral epithelia (22 cases) was also investigated. RESULTS: Strong syndecan-1 expression was observed on the surface of keratinocytes in normal epithelium. Immunopositivity was lost gradually as the extent of epithelial dysplasia increased. In normal epithelium, p53 and Ki-67 appeared mainly in the basal cell layer, while they were more widely distributed in leukoplakia. Specifically, significant changes were observed in the labeling index of p53 and Ki-67 in leukoplakia as epithelial dysplasia progressed from mild to moderate or severe. CONCLUSION: Our results reveal that overexpression of p53 protein and Ki-67 antigen, and down-regulation of syndecan-1 expression in the lower part of the epithelium, are associated with dysplastic changes. Therefore, the down-regulation of syndecan-1 expression may be the most important reliable marker for dysplastic changes.     

磷酸化p38促分裂原活化的蛋白激酶、尿激酶型纤溶酶原激活物及Ki-67在牙源性上皮性肿瘤中的表达

目的 检测磷酸化p38促分裂原活化的蛋白激酶(phosphorylated-p38 mitogen-activated protein kinase,p-p38MAPK)、尿激酶型纤溶酶原激活物(urokinase plasminogen activator,uPA)及Ki-67在牙源性上皮性肿瘤中的表达,探讨p-p38MAPK对牙源性上皮性肿瘤细胞增殖活性及侵袭性的影响.方法 根据2005年WHO关于牙源性肿瘤的分类标准,应用免疫组化方法检测p-p38MAPK、uPA和Ki-67在成釉细胞瘤(ameloblastoma,AB)、牙源性角化囊性瘤(keratocystic odontogenic tumour,KCOT)、牙源性钙化上皮瘤(calcifying epithelial odontogenic tumor,CEOT)、牙源性腺样瘤(adenomatoid odontogenic tumour,AOT)及牙源性钙化囊性瘤(calcifying cystic odontogenic tumour,CCOT)(以上为肿瘤组)和5例牙胚(对照组)中的表达.结果 p-p38MAPK在肿瘤组的阳性表达率为26%(17/65),在肿瘤细胞胞质和胞核均可见着色;uPA在肿瘤组的阳性表达率为78%(51/65),主要表现为肿瘤细胞胞质着色;Ki-67在肿瘤组的阳性表达率为95%(62/65),为弥散的肿瘤细胞胞核着色.p-p38MAPK、uPA和Ki-67在牙源性上皮性肿瘤的阳性表达率显著高于对照组(P＜0.05),三者的阳性表达呈正相关(P＜0.05).结论 p-p38MAPK信号传导通路可能以正性调节的方式调控uPA从而促进牙源性上皮性肿瘤的发生,可能是肿瘤发生、侵袭和增殖的重要途径之一.     

口腔鳞癌组织中Ki-67和p53蛋白的表达

目的 探讨口腔鳞癌组织中Ki-67和p53蛋白的表达及其与临床病理特征的关系。方法采用免疫组织化学S-P法对10例正常口腔黏膜组织、16例口腔白斑（OLK）组织、48例口腔鳞癌（OSCC）组织中的Ki-67和p53蛋白表达进行检测,结合患者临床病理资料进行分析,使用SPSS17.0 软件包对数据进行统计学处理。结果Ki-67蛋白在正常口腔黏膜组织、口腔白斑和口腔鳞癌组织中的阳性表达率分别为30.0%、56.3%和79.2%;p53的阳性表达率分别为0.0%、43.8%和70.8%,Ki-67和p53在正常黏膜组与口腔白斑和口腔鳞癌组差异均具有显著性（P<0.05）;Ki67蛋白在口腔鳞癌组织中的表达与肿瘤的临床分期、分化程度、有无淋巴结转移有关（P<0.05）,p53蛋白的表达与肿瘤的分化程度有关(P<0.05);Ki-67和p53蛋白在口腔鳞癌组织中的表达呈正相关（P<0.05）。结论Ki-67和p53蛋白在口腔鳞癌组织中高表达,可能在口腔鳞癌的发生、发展过程中起着重要作用。     

p53 and MDM2 expression in odontogenic cysts and tumours

OBJECTIVE: The aim of this report was to assess p53 and MDM2 expression in odontogenic cysts and tumours, as they are known to play important roles in cell proliferation and tumorigenesis. MATERIALS AND METHODS: The expression of p53 and MDM2 proteins was determined immunohistochemically in 51 formalin-fixed, paraffin embedded specimens of odontogenic cysts and tumours.RESULTS: No positivity to p53 was found in the cases studied. MDM2 expression in ameloblastoma was higher than in radicular cysts, but lower than that observed in odontogenic keratocysts. No difference was observed between MDM2 expression in radicular cyst and adenomatoid odontogenic tumour. The clear-cell odontogenic ameloblastoma presented strong immunoreaction to this antigen.CONCLUSIONS: The results suggest that MDM2 overexpression may be involved in the pathogenesis of some odontogenic lesions.     

Expression of p53, Ki-67, and EGFR in odontogenic keratocysts before and after decompression

BACKGROUND: Sixteen odontogenic keratocysts were examined morphologically and immunohistochemically for changes in proliferative activity before and after decompression using p53, Ki-67, and expression of growth factor (EGFR). METHODS: p53 and Ki-67 positivity was scored by counting 500 cells and then counting the number of brown staining nuclei out of these. EGFR was scored using guidelines for scoring Herceptest [Dako (Her-2)]. A Wilcoxon test was performed on the results. RESULTS: The values of Ki-67 and p53 before and after decompression were without significant change. There was no significant change in EGFR expression either. No correlation was found between inflammation or decompression time and expression of EGFR, p53, and Ki-67. The degree of change of the epithelium was varying, yet the reduction of the cysts size was considerable (18-100%- average 47.6%). CONCLUSION: The morphologic changes in the cysts could not be correlated with expression of Ki-67, p53 or EGFR, to the clinical reduction of the cysts or the time of decompression.     

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.     

Alterations of FHIT and P53 genes in keratocystic odontogenic tumor, dentigerous and radicular cyst

Background:  The purpose of this study was to determine fragile histidine triad (FHIT) and p53 protein expression, and to analyze FHIT and p53 gene status in keratocystic odontogenic tumor (KOT), dentigerous cysts (DC) and radicular cysts (RC).
Methods:  The methods used were immunohistochemistry and molecular genetic methods including loss of heterozygosity (LOH) and gene sequencing.
Results:  FHIT protein expression was different among groups. Aberrant expression was the highest in KOT, then in RC and DC. p53 protein expression was different among groups. LOH in paraffin-embedded specimens was detected in 22.6% and 12.9% for FHIT and p53 respectively. Mutation of p53 gene at codon 237 was observed in only two specimens (one KOT and one DC). Of the six frozen specimens, three exhibited FHIT gene LOH (two RC and one KOT). KOT showed loss of exons 6–7 at FHIT locus and mutation at codon 237 at p53 locus, but this could be a chance result.
Conclusion:  Aberrations of FHIT and p53 genes/proteins could be considered markers responsible for the development of odontogenic lesions.     

Comparison of angiogenesis in keratocystic odontogenic tumours, dentigerous cysts and ameloblastomas

Objective:  The aim of the present study was to evaluate and compare angiogenesis in keratocystic odontogenic tumours, dentigerous cysts (DCs) and ameloblasomas using monoclonal antibody against CD34.
Materials and methods:  Microvessel density was assessed in a total of 53 cases including 20 keratocystic odontogenic tumours, 13 DCs and 20 ameloblastomas (14 solid and six unicystic variants). Microvessel density was expressed as the mean number of microvessels per high-power-field.
Results:  Statistically significant differences in mean microvessel density were observed between keratocystic odontogenic tumours, DCs and solid ameloblastomas ( P  < 0.001). Mean microvessel density was significantly higher in solid ameloblastomas compared with both keratocystic odontogenic tumours and DCs; and was also significantly higher in keratocystic odontogenic tumours than in DCs.
Conclusion:  Within the limitations of the present study, it can be suggested that angiogenesis may be one of the mechanisms possibly contributing to the different biological behaviours of keratocystic odontogenic tumours, DCs and solid ameloblastomas.     

Prevalence of developmental odontogenic cysts in children and adolescents with emphasis on dentigerous cyst and odontogenic keratocyst (keratocystic odontogenic tumor)

Objective. To investigate the incidence and prevalence of developmental odontogenic cysts in children and adolescents and compare the features of the two most common types, dentigerous cyst and keratocystic odontogenic tumor (KCOT). Study design. A retrospective review in a series of 369 patients with all histological diagnoses of developmental odontogenic cysts in children (≤12 years) and adolescents (13–18 years) was conducted. Results. Among these, 361 (97.8%) patients were diagnosed as dentigerous cyst (n = 281) and KCOT (n = 80), with the male-to-female ratios of dentigerous cyst and KCOT both being 2:1. The average age of the patients with KCOT was older than that of those with dentigerous cyst (14.7 years vs 11.8 years, p < 0.001). Dentigerous cyst (59.1%) was more common in children, but KCOT (78.8%) was more common in adolescents (p < 0.001). Dentigerous cyst (57.6%) predominantly located on the maxilla, but KCOT (60.3%) predominantly located on the mandible (p = 0.010). Conclusions. Adolescent patients with lesions located on the mandible would favor KCOT over dentigerous cyst. This study aids in better knowledge of the prevalence of developmental odontogenic cysts in a large pediatric population, and shows that a well-supported early diagnosis is indispensable for a more adequate treatment.     

A comparative study of epithelial cell proliferation between the odontogenic keratocyst, orthokeratinized odontogenic cyst, dentigerous cyst, and ameloblastoma

OBJECTIVES: The aim of the present study was to compare the proliferation index of the epithelial cells between odontogenic keratocysts (OKC), orthokeratinized odontogenic cysts (OOC), dentigerous cysts (DC), and ameloblastomas. MATERIALS AND METHODS: The proliferation index, employing a novel cell proliferation marker IPO-38, was studied by the immunohistochemical technique in 10 OKC, seven OOC, eight DC and 10 ameloblastomas. RESULTS: The ameloblastoma had no higher labeling index (LI) of IPO-38 than the OKC (P = 0.910) but had higher LI than the OOC (P = 0.001) and DC (P = 0.000); the OKC had higher LI than the OOC (P = 0.002) and DC (P = 0.000); and the OOC had higher LI than the DC (P = 0.011). IPO-38-positive cells in the OKC and OOC were located principally in the suprabasal cell layers while the ameloblastoma were found in the peripheral portion in particularly, the follicular and plexiform types. CONCLUSION: These findings support previous studies that the proliferation indices are useful in predicting the different biological behavior of the odontogenic lesions and the OKC should be regarded as a benign tumor rather than simply an odontogenic cyst.     

A comparative stereologic and ultrastructural study of blood vessels in odontogenic keratocysts and dentigerous cysts

Blood vessels were investigated both stereologically and ultrastructurally in keratocyst and dentigerous cyst. The volume and surface densities of blood vessels in 15 keratocysts and dentigerous cysts were analyzed stereologically. No significant differences were found between them using these parameters, suggesting that their overall vascularity may be similar. However, the ultrastructural study showed marked differences between blood vessels in these two types of cysts. It was observed that fenestrated capillaries were found only in keratocysts. In addition, degeneration of endothelial lining associated with thrombosis was also a prominent feature of this cyst. While ruptured endothelium, narrow lumen and Weibel-Palade bodies were characteristic of vessels in dentigerous cyst. The presence of fenestrated capillaries in keratocyst and not in dentigerous cyst might indicate a rapid transfer of fluid to meet the demand of the relatively active proliferating epithelium, which may be promoted by growth factors released from platelets in those thrombosed vessels.     

Ameloblastoma, calcifying epithelial odontogenic tumor, and glandular odontogenic cyst show a distinctive immunophenotype with some myoepithelial antigen expression

Background:  Odontogenic neoplasms have some morphologic overlap with salivary gland neoplasms, many of which show myoepithelial differentiation. In the 1980s, an ultrastructural study identified a population of myoepithelial-like cells in calcifying epithelial odontogenic tumor. Myoepithelial derived tumors have since been shown to have distinct immunohistochemical profiles.
Methods:  We examined a series of odontogenic neoplasms, including 11 ameloblastomas, four calcifying epithelial odontogenic tumors, five glandular odontogenic cysts (GOCs), and five keratocystic odontogenic tumors with a panel of myoepithelial-associated immunohistochemical stains. We also assessed representative control examples of oral mucosa, odontogenic rests, and dentigerous cysts.
Results:  All of the neoplastic and non-neoplastic oral epithelium-derived entities share a p63-positive, high molecular weight cytokeratin (CK5/6)-positive immunophenotype. Calponin reactivity was at least focally present in two of four calcifying epithelial odontogenic tumors, three of five GOCs, and 10 of 11 ameloblastomas; the sole completely non-reactive ameloblastoma represents a lung metastasis. One case of calcifying epithelial odontogenic tumor was focally positive for glial fibrillary acidic protein. However, other more definitive markers of myoepithelial differentiation, including S-100 and smooth muscle actin, were negative. Two of three calcifying epithelial odontogenic tumors and five of five GOCs were also positive for a low molecular weight cytokeratin (CK7).
Conclusions:  Ameloblastomas, GOCs, and calcifying epithelial odontogenic tumors show a distinctive immunophenotype which overlaps with that of myoepithelial-derived salivary gland neoplasms but does not provide definitive support for myoepithelial differentiation.     

Expression of p53, Ki-67 and cytokeratin-4 (CK4) in oral papillomas

P53 is overexpressed in more than 50% of all human cancers. A previous study suggested that p53 was also overexpressed in oral papillomas. This study was carried out to investigate whether p53 expression was correlated with expression of the cellular proliferation marker Ki-67 and the epithelial differentiation marker cytokeratin-4 (CK4) in oral papillomas. Formalin-fixed paraffin-embedded sections of 30 oral papilloma specimens and 30 unmatched normal oral mucosal specimens were processed for immunohistochemistry, using an avidin-biotin- peroxidase procedure and monoclonal antibodies. A semiquantification analysis on p53 and Ki-67 labeling indices was performed. Twenty-eight of 30 (93%) papilloma specimens were positive for p53. The percentage of p53–positive cells in the basal layer was 60.4± 14.8 (mean±SD. n =28). and that of Ki-67–positive cells was 26.7± 14.4. There was no correlation between expression of p53 and that of Ki-67. Expression of CK4 was inversely correlated with the expression of Ki-67 but not correlated with the expression of p53.     

Immunohistochemical detection of factors related to cellular proliferation and apoptosis in radicular and dentigerous cysts

Introduction

This study proposed to investigate aspects of cell proliferation and death in the epithelium of radicular (RCs) and dentigerous (DCs) cysts.

Methods

Serial sections of 17 RCs and 9 DCs were prepared for immunohistochemical detection of caspase-3, Bcl-2, and Ki-67 antigens.

Results

Caspase-3 was detected mainly in the suprabasal and superficial epithelial cells of RCs and DCs, whereas Ki-67 was detected predominantly in the basal layer. Both markers had significant expression in hyperplastic epithelium related to an intense inflammation in the capsule. Immunoreactivity for Bcl-2 was restricted to the basal layer and was significantly higher in atrophic epithelium of DCs than that of RCs.

Conclusions

These results suggest that epithelial proliferation is balanced by apoptosis and that the presence of inflammation inhibits the Bcl-2 expression. DCs and RCs have different formation mechanisms but have similar biological behavior in the presence of intense inflammatory infiltrate.     

Immunohistological evaluation of Ki-67, p63, CK19 and p53 expression in oral epithelial dysplasias

BACKGROUND: Oral squamous cell carcinoma develops through a multistep of genetic mutations, and the process can be morphologically recognized as oral epithelial dysplasia. To evaluate the hypothesis that distributional alterations of proliferating and stem cells may be a useful index to estimate the grading and development of epithelial dysplasia, we examined the distribution patterns according to stratified cell layers. METHODS: Sixty-two oral dysplasia cases according to the histological grades were immunohistologically examined and the nuclear expression of Ki-67 and p63 antigens was counted according to epithelial layers as labeling index. RESULTS: The Ki-67 labeling index in the basal and suprabasal layers and that of p63 in the basal layer showed a significant difference between low- and high-grade groups of epithelial dysplasia. CONCLUSION: The architectural alteration of proliferating cell and stem cell distribution in the layers of epithelial dysplasias may provide useful information to evaluate the grading of oral epithelial dysplasias.