Ki-67 and MCM-2 in dental follicle and odontogenic cysts: the effects of inflammation on proliferative markers

Immunohistochemical Comparison of Ki-67 and MCM-3 in Odontogenic Cysts: An Observational Study

Odontogenic cysts are a diverse group of pathologic entities with different proliferation potential, leading to variations in their biological behavior. One of the most cited proliferation markers used in diagnostic histopathology is Ki-67. Another group of proteins recently investigated is minichromosome maintenance (MCM-3) and its expression has been evaluated in several odontogenic lesions but the results were controversial. Thus, the present study endeavored to compare the expression of MCM-3 and Ki-67 in odontogenic cysts. Furthermore, a pioneer attempt was made to evaluate the sensitivity of these markers to inflammation. A total of 101 cases (37 dentigerous cysts, 37 odontogenic keratocysts, and 27 radicular cysts) were included. Immunohistochemical expression of Ki-67 and MCM-3 were investigated using a labeling index (LI). In addition, they were scored for inflammation, followed by correlation with both markers. The data obtained were subjected to statistical analysis ( P <0.05). Overall, a higher LI of MCM-3 than Ki-67 was obtained in all study groups along with a positive correlation of Ki-67 LI with inflammation. Thus, MCM-3 proteins proved to be a more accurate means to determine the proliferation potential and were not sensitive to external stimuli like inflammation than conventional markers, such as Ki-67.

P63 and Ki-67 expression in radicular cyst

Objectives

The aim of the current study was to identify the expression of P63 and its relation to odontogenic epithelial cell proliferation, severity of the inflammatory infiltrate and size of radicular cysts (RCs).

Methods

In this retrospective cross-sectional study, 30 cases of paraffin-embedded RCs were randomly selected from the archive. P63 and Ki-67 expression was assessed by immunohistochemistry.

Results

Epithelial P63 expression was absent in four (13.3%), weak in 10 (33.3%), and moderate in 16 (53.3%) cases. In the connective tissue wall of RC, P63 expression was absent in two (6.7%) cases, weak in 24 (80.0%) cases, and moderate in four (13.3%) cases. Ki-67 was found to be weakly expressed in 12 (40.0%) cases, moderately expressed in 13 (43.3%), and strongly expressed in five (16.7%) cases. No correlation was found between Ki-67 expression in odontogenic epithelium and P63 expression in the odontogenic epithelium (rho = 0.110, p = .563) or fibrous capsule (rho = 0.160, p = .399). Nevertheless, we found a positive correlation between Ki-67 expression in the odontogenic epithelium and the size of the RC (rho = 0.450, p = .013). The inflammatory infiltrate was negatively correlated with P63 expression in the odontogenic epithelium (rho = -0.428, p = .018), and with the size of cysts (rho = -0.728, p < .001).

Conclusions

There is a high expression of P63 throughout the odontogenic epithelium and connective tissue capsule of the RC. P63 expression in the odontogenic epithelium is negatively correlated with the degree of the inflammatory infiltrate but not with epithelial cell proliferation or the size of the cyst.

Management of radicular cyst associated with primary teeth using decompression: a retrospective study

BACKGROUND

Radicular cysts arising from primary teeth are rare. Enucleation and marsupialization or decompression are treatment approach to odontogenic cysts. Decompression known to achieve good results in various cysts is widely used in clinic. This study aims to evaluate the efficiency of decompression in reducing radicular cysts associated with primary teeth in children.

METHODS

Cases of radicular cysts associated with primary teeth treated by decompression were reviewed in the present study. Clinical information and radiologic data of pre and post decompression were measured and analyzed.

RESULTS

Twenty-three patients treated for 25 cysts were included. All lesions with mean initial area 3.66 ± 2.00 cm² were reduced after decompression time ranging 2 to 10 months. Mean rate of reduction was 0.77 ± 0.44 cm²/mo and large lesions (> 3.5 cm²) had a significantly higher reduction rate compared to smaller ones (< 3.5 cm²) (P < 0.00). All effected succedaneous teeth erupted after treatment at follow-up while 12 (46%) of them had root development problems.

CONCLUSIONS

Decompression represents superiority as an effective and less invasive treatment in radicular cysts associated with primary teeth.

TRIAL REGISTRATION

This study was retrospectively registered in the Ethics Committee of Ninth People's Hospital Affiliated with Shanghai JiaoTong University School of Medicine (No.SH9H-2022-T158-1).

Factors Influencing the Aggressive Behavior of Odontogenic Keratocyst: A Narrative Review

During odontogenesis, the dental lamina disintegrates, leaving behind the remnants. Odontogenic pathologies such as cysts and tumors can arise from these remnants. The odontogenic keratocyte (OKC) arises from dental lamina remnants. Among the cysts, the odontogenic keratocyst is the most controversial. There is convincing evidence that inflammation plays a significant role in the pathogenesis and expansion of OKCs. Several factors mediate the proliferative capacity of the epithelial lining. The presence of mast cells close to the epithelial lining, cystic pressure build-up by vascular endothelial growth factors (VEGFs), and other cytokines contribute to the cystic expansion. Fibroblast activation by inflammation in the connective tissue stroma and changes in the epithelial lining are responsible for the aggressive nature of OKC. The use of molecular methodologies gives more profound insights into the factors influencing the progression of the lesion and helps develop newer treatment modalities for OKC. This review describes the characteristics that determine the aggressive behavior of this unique cyst.

Comparative Metabolomics Reveals the Microenvironment of Common T-Helper Cells and Differential Immune Cells Linked to Unique Periapical Lesions

Periapical abscesses, radicular cysts, and periapical granulomas are the most frequently identified pathological lesions in the alveolar bone. While little is known about the initiation and progression of these conditions, the metabolic environment and the related immunological behaviors were examined for the first time to model the development of each pathological condition. Metabolites were extracted from each lesion and profiled using gas chromatography-mass spectrometry in comparison with healthy pulp tissue. The metabolites were clustered and linked to their related immune cell fractions. Clusters I and J in the periapical abscess upregulated the expression of MMP-9, IL-8, CYP4F3, and VEGF, while clusters L and M were related to lipophagy and apoptosis in radicular cyst, and cluster P in periapical granuloma, which contains L-(+)-lactic acid and ethylene glycol, was related to granuloma formation. Oleic acid, 17-octadecynoic acid, 1-nonadecene, and L-(+)-lactic acid were significantly the highest unique metabolites in healthy pulp tissue, periapical abscess, radicular cyst, and periapical granuloma, respectively. The correlated enriched metabolic pathways were identified, and the related active genes were predicted. Glutamatergic synapse (16–20),-hydroxyeicosatetraenoic acids, lipophagy, and retinoid X receptor coupled with vitamin D receptor were the most significantly enriched pathways in healthy control, abscess, cyst, and granuloma, respectively. Compared with the healthy control, significant upregulation in the gene expression of CYP4F3, VEGF, IL-8, TLR2 (P < 0.0001), and MMP-9 (P < 0.001) was found in the abscesses. While IL-12A was significantly upregulated in cysts (P < 0.01), IL-17A represents the highest significantly upregulated gene in granulomas (P < 0.0001). From the predicted active genes, CIBERSORT suggested the presence of natural killer cells, dendritic cells, pro-inflammatory M1 macrophages, and anti-inflammatory M2 macrophages in different proportions. In addition, the single nucleotide polymorphisms related to IL-10, IL-12A, and IL-17D genes were shown to be associated with periapical lesions and other oral lesions. Collectively, the unique metabolism and related immune response shape up an environment that initiates and maintains the existence and progression of these oral lesions, suggesting an important role in diagnosis and effective targeted therapy.

Revisiting the human dental follicle: From tooth development to its association with unerupted or impacted teeth and pathological changes

Dental follicles are involved in odontogenesis, periodontogenesis, and tooth eruption. Dental follicles are unique structures, considering that their remnants can persist within the jawbones after odontogenesis throughout life if the tooth does not erupt. Pathological changes may occur in these tissues as individuals age. The changes range from benign to life threatening. Thus, the assessment of age-related changes in dental follicles associated with unerupted teeth is of paramount importance. In this review, we summarize the physiological roles and changes in dental follicles in odontogenesis, tooth eruption, and aging, in addition to the pathological changes associated with these structures. We encourage investigators to consider this peculiar tissue as a unique model and explore its potential to clarify its importance from the viewpoints of developmental biology, tissue physiology, and pathology.

Proliferative and anti-apoptotic indices of unicystic ameloblastoma, odontogenic keratocyst, dentigerous cyst and radicular cyst

Objective:

The aim of this study is to compare the proliferative capacity and antiapoptotic capacity of unicystic ameloblastoma (UA), odontogenic keratocyst (OKC), dentigerous cyst (DC) and radicular cyst (RC) by assessing the Ki-67 labeling index (LI) and Bcl-2 LI, respectively.

Materials and Methods:

Formalin-fixed, paraffin-embedded tissue blocks of twenty-three histopathologically diagnosed UAs, 6 OKCs, 8 DCs and 10 RCs were selected from the archival specimens. Five micrometer thick sections of tissue blocks of the lesions were processed for immunohistochemical staining with Ki-67 and Bcl-2. The Ki-67 LI and Bcl-2 LI were determined for the cases with a positive reaction.

Results:

Ki-67 expression was seen in 6 (26.1%) cases of UA, 4 (66.7%) OKC, 1 (12.5%) DC and 1 (10.0%) RC. There was a statistically significant difference between the mean Ki-67 LI of UA and OKC (P = 0.024). Bcl-2 expression was seen in 16 (69.6%) UA, 5 (83.3%) OKC, 5 (62.5%) DC and 5 (50.0%) RC. The mean Bcl-2 LI of UA was significantly higher than that of DC (P = 0.048). Furthermore, cases of OKC had significantly higher mean Bcl-2 LI compared to DC (P = 0.026) and RC (P = 0.049).

Conclusion:

This study suggests that the Ki-67 LI may help in differentiating OKC from UA. The Bcl-2 LI may be useful in differentiating UA from DCs, and differentiating OKC from DC and RC.

Computerized Evaluation of the Immunoexpression of Ki-67 Protein in Odontogenic Keratocyst and Dentigerous Cyst

Evaluation and comparison of odontogenic keratocysts and detigerous cysts immunoexpression and immunostaining intensities of Ki-67 antigen by assessing the whole extent of the epithelium (all epithelium layers in combination) and each layer individually. Ki-67 immunoexpression was evaluated in 15 odontogenic keratocysts and 6 dentigerous cysts using automated methods and the Aperio Technologies Inc. computer system. No statistically significant differences were observed in immunoexpression nor in immunostaining intensities between both lesions. Also, no statistically significant differences were found between odontogenic keratocysts from maxilla versus mandible nor primary versus recurrent. However, odontogenic keratocyst showed a significantly higher cellular proliferation index in the suprabasal layers compared to the basal layer. Assessment of the cellular proliferation index through a computerized system enabled the evaluation of all epithelial tissue without field selection. The increased Ki-67 immunoexpression in suprabasal layers of odontogenic keratocyst suggests a different biological behavior and more aggressive proliferation potential when compared to dentigerous cyst. The same result was found in recurrent odontogenic keratocysts when compared with primary ones. The odontogenic keratocysts of the maxilla and mandible have similar Ki-67 immunoexpression. The evaluation of cellular proliferation only by immunohistochemical analysis with Ki-67 antigen does not provide enough data to elucidate the biological behavior of odontogenic keratocyst.

Benign odontogenic ghost cell lesions revisited and new considerations on dysplastic dentin

OBJECTIVES

This study aimed to revisit benign odontogenic ghost cell lesions (BOGCL) by hematoxylin and eosin staining and immunohistochemistry.

MATERIALS AND METHODS

Thirty cases of calcifying odontogenic cyst (COC) and 6 cases of dentinogenic ghost cell tumor (DGCT) were selected for histopathological and immunohistochemical analysis. Sections stained for cytokeratin (K) 14, K-19, amelogenin, collagen type 1 (COL-1), and dentin matrix acidic phosphoprotein 1 (DMP-1) were evaluated using qualitative analysis. Sections stained for Ki-67 and minichromosome maintenance protein-2 (MCM-2) were evaluated using semi-quantitative analysis.

RESULTS

A morphologic overlap was noticed in all BOGCL. Moreover, no differences were detected in the expression of K-14 and K-19. The expression of proliferative markers Ki-67 and MCM-2 was similar between cystic and tumor lesions (p > .05). The presence of COL-1 and absence of amelogenin in the so-called dysplastic dentin, associated with its histologic pattern, suggest that this is in fact an enameloid-like tissue.

CONCLUSIONS

The dysplastic dentin should be considered an enameloid-like tissue in these lesions.

CLINICAL RELEVANCE

The similarity in histology, protein expression, and proliferative marker indices between COC and DGCT suggest that they are a sole entity and likely represent types of the same neoplasia.

MCM3 and Ki67 proliferation markers in odontogenic cysts and ameloblastoma

Background

MCM3 is a marker of proliferation that has been used as a diagnostic or prognostic marker in many pathologic lesions.

Purpose

The purpose of this study is to investigate the proliferative activity of dentigerous cysts, odontogenic keratocyst and ameloblastoma using minichromosome maintenance 3 (MCM3) and compare it with Ki-67 proliferation marker.

Methods

In this cross-sectional study, 40 cases including 11 cases of dentigerous cyst, 14 odontogenic keratocyst, and 15 ameloblastoma were included. Immunohistochemical expression of MCM3 and Ki-67 were investigated and compared statistically using ANOVA, Chi-square, Tukey and Spearman's correlation tests.

Results

All subjects were positive for Ki-67 and MCM3. There was a significant difference in MCM3 and Ki-67 expression among all groups. Compared to Ki-67, MCM3 exhibited a higher level of expression. Ameloblastoma and odontogenic keratocyst revealed higher expression rate of both markers in comparison to dentigerous cysts.

Conclusion

The results showed MCM3 and Ki67 expression in the most common odontogenic cysts and tumors, especially more aggressive lesions. MCM3 might have a role in pathogenesis of these lesions and could be a reliable marker for assessing proliferation activity.

Mucous Cell Prosoplasia in Oral Pathologies: A Brief Review

One of the enigmas in cell differentiation process is prosoplasia, which is contemplated as forward differentiation. A well-known example of prosoplastic switch is mucous cell prosoplasia, which is the transformation of a simple squamous epithelial cell into mucous secreting cell. Numerous theories have been proposed for histogenesis of this phenomenon, which are comprehensively discussed in the present paper. Oral pathologies like odontogenic cysts and salivary gland tumours show mucous prosoplasia quite often; sometimes leading to diagnostic difficulties. In the present paper, efforts have been made to comprehensively discuss diverse aspects of mucous prosoplasia like histogenesis, theories and diagnostic importance in various oral pathologies.

P53 Protein Expression in Dental Follicle, Dentigerous Cyst, Odontogenic Keratocyst, and Inflammatory Subtypes of Cysts: An Immunohistochemical Study

OBJECTIVES

An odontogenic keratocyst (OKC) is a developmental odontogenic cyst with aggressive clinical behavior. This cyst shows a different growth mechanism from the more common dentigerous cyst and now has been renamed as a keratocystic odontogenic tumor (KCOT). Inflammation can assist tumor growth via different mechanisms including dysregulation of the p53 gene. This study aims to assess and compare the expression of tumor suppressor gene p53 in inflamed and non-inflamed types of OKC and dentigerous cyst.

METHODS

Immunohistochemical expression of p53 was assessed in 14 cases of dental follicle, 34 cases of OKC (including 18 inflamed OKCs), and 31 cases of dentigerous cyst (including 16 inflamed cysts).

RESULTS

The mean percentage of p53 positive cells was 0.7% in dental follicles, 5.4% in non-inflamed OKCs, 17.3% in inflamed OKCs, 1.2% in non-inflamed dentigerous cysts, and 2.2% in inflamed dentigerous cysts. The differences between the groups were statistically significant (p < 0.050) except for the difference between inflamed and non-inflamed dentigerous cysts, and between dental follicle and non-inflamed dentigerous cyst.

CONCLUSIONS

The difference in p53 expression in OKC and dentigerous cyst can explain their different growth mechanism and clinical behavior. Inflammation is responsible for the change in behavior of neoplastic epithelium of OKC via p53 overexpression.

P63 and Ki-67 Expression in Dentigerous Cyst and Ameloblastomas

STATEMENT OF THE PROBLEM

P63 gene is a member of TP53 and its homologous gene family. Its expression was observed in some odontogenic lesions, more expression in aggressive lesions.

PURPOSE

This study aimed to investigate the possible diagnostic impact of P63 protein on dentigerous cysts and various types of ameloblastoma. Its expression with Ki-67 proliferation marker was also compared.

MATERIALS AND METHOD

This cross-sectional retrospective study was enrolled on 25 cases of dentigerous cyst including 21 unicystic ameloblastomas and 17 conventional ameloblastomas. The expression of P63 and Ki-67 was assessed by immunohistochemical (IHC) examinations. Data were analyzed by employing Mann-Whitney and correlation coefficient tests.

RESULTS

P63 expression was significantly higher in ameloblastoma than unicystic ameloblastoma and dentigerous cysts. There was no significant difference between unicystic ameloblastoma and dentigerous cyst in P63 expression. A 90% cut-off point was obtained for basal layer which gave 88% sensitivity and 78% specificity to distinguish more invasive lesions from others. There was not any correlation between P63 and Ki-67 immunostaining in the three study groups.

CONCLUSION

More aggressiveness and more invasiveness of odontogenic lesions depicted higher rate and also more intensive expression of P63. Moreover, the expression of P63 protein had not any correlation with Ki-67 protein in dentigerous cysts and ameloblastomas.

Radicular Cyst: An Update of the Biological Factors Related to Lining Epithelium

INTRODUCTION

Radicular cysts are common lesions in daily dentistry practice. However, the mechanisms related to epithelial lining formation and cavity growth are not fully understood. Therefore, the purpose of this article was to review the biological factors implicated in these process.

METHODS

Literature was selected through a search of PubMed electronic databases matching the following key words in the title or abstract: "cyst" OR "granuloma" OR "abscess" AND "radicular" OR "apical" OR "periapical" AND "epithelium" OR "epithelial" OR "epithelial lining." The PubMed database was searched for articles published between 1975 and 2014. Only English language was applied to the search.

RESULTS

The literature search yielded a total of 187 articles. After duplicate references were discarded, a subsequent search at the title and abstract level revealed 42 articles for full-text reading. The articles were categorized into 5 main subtopics: (1) cell proliferation, cell cycle, and apoptosis; (2) extracellular matrix constituents; (3) inflammatory components; (4) bone metabolic factors and; (5) others. These subtopics described the characteristics of radicular cysts focusing on the epithelial tissue effects.

CONCLUSIONS

Several factors from different sources (epithelial cells, stromal cells, extracellular matrix, and bone matrix) were implicated on apical cyst pathogenesis. Probably a combination of many factors involving an epithelial-stromal interaction is responsible for the sustenance and growth of apical cysts.

Study of the relationship between mononuclear inflammatory infiltrate and Ki-67 and basement membrane and extracellular matrix protein expression in radicular cysts

AIM

To evaluate the relationship between mononuclear inflammatory infiltrate and the expression of a proliferative immunomarker (Ki-67) as well as to evaluate basement membrane and extracellular matrix proteins (laminin and collagen type IV) in radicular cysts and dentigerous cysts (DC).

METHODOLOGY

Immunohistochemical analyses were performed in heavily inflamed radicular cysts (HIRC), slightly inflamed radicular cysts (SIRC) and DC (n = 20) using Ki-67 (Dako(®) , 1 : 50), anticollagen type IV (DBS(®) , 1 : 40) and antilaminin (DBS(®) , 1 : 20). The data were analysed using anova/Tukey's test (Ki-67) and Kruskal-Wallis/Dunn's test (collagen type IV and laminin) (P < 0.05).

RESULTS

The immunoexpression of Ki-67 was significantly greater in the SIRC group compared with the HIRC and DC (P = 0.0040). Likewise, the immunoexpression of collagen type IV in the basement membrane of the SIRC group was significantly more continuous (P = 0.0475) than in the HIRC group. DC had significantly less collagen type IV in extracellular matrix immunoexpression than HIRC and SIRC (P = 0.0246). Laminin was absent in the basement membrane in the SIRC and DC groups, and the extracellular matrix of the HIRC was weak and punctate.

CONCLUSION

The presence of inflammatory factors in the radicular cyst wall modified the expression of proliferation factors in the epithelial lining and the expression of collagen type IV and laminin in the basement membrane, but did not modify extracellular matrix behaviour in radicular cysts.

Analysis of the proliferative potential of odontogenic epithelial cells of pericoronal follicles

AIM

To evaluate the proliferative potential and the cell proliferation rate of odontogenic epithelial cells.

MATERIALS AND METHODS

Forty-two cases of pericoronal follicles of impacted third molars were submitted to silver impregnation technique for quantification of argyrophilic nucleolar organizer regions (AgNOR) and immunohistochemical staining for EGFR and Ki-67. For AgNOR quantification, the mean number of active nucleolar organizer regions per nucleus (mAgNOR) and the percentage of cells with 1, 2, 3 and 4 or more AgNORs per nucleus (pAgNOR) were quantified. Ki-67 immunolabeling was quantified, whereas for EGFR, a descriptive analysis of staining patterns (membrane, cytoplasm or membrane + cytoplasm positivity) was performed. We evaluated the reduced epithelium of the enamel organ and/or islands of odontogenic epithelium present in the entire connective tissue.

RESULTS

mAgNOR were 1.43 (1.0-2.42) and were significantly different among pericoronary follicles from upper and lower teeth (p = 0.041). Immunostaining of Ki-67 was negative in all cases. EGFR immunolabeling was found mainly in the cytoplasm and was more intense in islands and cords when compared to reduced epithelium of the enamel organ.

CONCLUSION

Odontogenic epithelial cells of some pericoronal follicles have proliferative potential, suggesting their association with the development of odontogenic lesions.

CLINICAL SIGNIFICANCE

The authors suggest that nonerupted, especially of the lower teeth, should be monitored and if necessary removed.

A comparative study of PCNA and Ki-67 expression in dental follicle, dentigerous cyst, unicystic ameloblastoma and ameloblastoma

Various cell proliferation markers are used as diagnostic and prognostic tools in oral lesions. Simultaneous evaluation of these markers can increase the precision of estimation of the proliferative status of different tissues. In this study we investigated the expression of PCNA and Ki-67 as markers of cell proliferation in 15 paraffin embedded samples of each dental follicle, dentigerous cyst, unicystic ameloblastoma and ameloblastoma belonging to a total of 30 male and 30 female paients using immunohistochemistry method. Expression levels based on the intensity and the percentage of stained cells was separately analyzed for each marker with chi-square test, the results of which were significant for the two markers (P<0.05). The correlation coefficient between the two markers was found to be 0.88. A significant difference in the expression of Ki-67 and PCNA was observed in the four types of studied lesions.