Expression of SOX2 and OCT4 in odontogenic cysts and tumors

Histone H3K9 Methylation Is Differentially Modified in Odontogenic Cyst and Tumors

OBJECTIVES

 Histone modification in odontogenic lesions is mostly unexplored. Trimethylation of histone H3 at lysine residue 9 (H3K9Me3) has been studied in various pathologic conditions and showed biological significance promising for future therapeutic application. This study aimed to investigate the level and clinical relevance of the H3K9Me3 histone modification in odontogenic cysts and tumors.

MATERIALS AND METHODS

 A total of 105 cases of odontogenic lesions, comprising 30 odontogenic keratocysts (OKCs), 30 adenomatoid odontogenic tumors (AOTs), 30 ameloblastomas, and 15 dental follicles, were included in the study. The paraffin-embedded tissues were immunohistochemically stained for H3K9Me3. Both the intensity and the distribution of staining were evaluated and calculated as H-score. The correlation between the H3K9Me3 expression and the clinical characteristics of each lesion was evaluated.

STATISTICAL ANALYSIS

 The Kruskal-Wallis test followed by Bonferroni's correction was performed to assess the differences in H-score among groups. In addition, Pearson's chi-squared test or Mann-Whitney U test was used to analyze potential factors that could affect protein expression.

RESULTS

 The reduced enamel epithelium of the dental follicle showed uniformly strong H3K9Me3 expression. All odontogenic cysts and tumors examined demonstrated a significantly reduced H3K9Me3 level compared with dental follicles. The AOT showed the lowest H3K9Me3 level, followed by OKC and ameloblastoma. Its immunoreactivity was mainly localized in the basal and parabasal cells of OKC and the whorled/duct-like structures of AOT. Ameloblastoma exhibited marked variation in the H3K9Me3 level among cases. Notably, the upregulated H3K9Me3 was related to multilocularity of OKC and ameloblastoma.

CONCLUSIONS

 Histone H3K9 methylation is differentially expressed in odontogenic cysts and tumors. This epigenetic modification may contribute to the pathogenesis and aggressive behavior of odontogenic lesions.

Surrogate Immunohistochemical Markers of Proliferation and Embryonic Stem Cells in Distinguishing Ameloblastoma from Ameloblastic Carcinoma

PURPOSE

The current study aimed to investigate the use of surrogate immunohistochemical (IHC) markers of proliferation and stem cells to distinguish ameloblastoma (AB) from ameloblastic carcinoma (AC).

METHODS

The study assessed a total of 29 ACs, 6 ABs that transformed into ACs, and a control cohort of 20 ABs. The demographics and clinicopathologic details of the included cases of AC were recorded. The Ki-67 proliferation index was scored through automated methods with the QuPath open-source software platform. For SOX2, OCT4 and Glypican-3 IHC, each case was scored using a proportion of positivity score combined with an intensity score to produce a total score.

RESULTS

All cases of AC showed a relatively high median proliferation index of 41.7%, with statistically significant higher scores compared to ABs. ABs that transformed into ACs had similar median proliferation scores to the control cohort of ABs. Most cases of AC showed some degree of SOX2 expression, with 58.6% showing high expression. OCT4 expression was not seen in any case of AC. GPC-3 expression in ACs was limited, with high expression in 17.2% of ACs. Primary ACs showed higher median proliferation scores and degrees of SOX2 and GPC-3 expression than secondary cases. Regarding SOX2, OCT4 and GPC-3 IHC expression, no statistically significant differences existed between the cohort of ABs and ACs.

CONCLUSION

Ki-67 IHC as a proliferation marker, particularly when assessed via automated methods, was helpful in distinguishing AC from AB cases. In contrast to other studies, surrogate IHC markers of embryonic stem cells, SOX2, OCT4 and GPC-3, were unreliable in distinguishing the two entities.

Expression of Fascin and SALL4 in odontogenic cysts and tumors: an immunohistochemical appraisal

Background

Various stemness markers (SOX2, OCT4, and NANOG) have been studied in odontogenic cysts and tumors. However, studies on SALL4 having similar properties of stemness has not been documented. Additionally, insight into fascin as a migratory molecule is less explored. In this study, the expression of SALL4 and fascin were evaluated in ameloblastoma, adenomatoid odontogenic tumor (AOT), odontogenic keratocyst (OKC), dentigerous cyst (DC), radicular cyst (RC), and calcifying odontogenic cyst (COC).

Methods

Semi-quantitative analysis of fascin and SALL4 immuno-positive cells was done in a total of 40 cases of ameloblastoma (11 plexiform, 12 follicular, 12 unicystic, and 5 desmoplastic) variants, 6 cases of AOT, 15 each of OKC, DC, RC and 5 of COC. Chi-square test was applied to evaluate the association between SALL4 and fascin expression in odontogenic cysts and tumors.

Results

Fascin immunopositivity was observed in peripheral ameloblast-like cells, and the expression was weak or absent in stellate reticulum-like cells. A moderate to weak immune-reactivity to SALL4 was observed in the cytoplasm of ameloblastoma, epithelial cells of dentigerous and radicular cysts, having a marked inflammatory infiltrate, which was an interesting observation. COC and AOT had negative to weak expressions. No recurrence has been reported.

Conclusions

Expression of fascin in ameloblastomas elucidate their role in motility and localized invasion. Its expression in less aggressive lesions like DC, COC, AOT will incite to explore the other functional properties of fascin. SALL4 expression in the cytoplasm of odontogenic cysts and tumors may represent inactive or mutant forms which requires further validation.

Spatiotemporal cellular dynamics and molecular regulation of tooth root ontogeny

Tooth root development involves intricate spatiotemporal cellular dynamics and molecular regulation. The initiation of Hertwig's epithelial root sheath (HERS) induces odontoblast differentiation and the subsequent radicular dentin deposition. Precisely controlled signaling pathways modulate the behaviors of HERS and the fates of dental mesenchymal stem cells (DMSCs). Disruptions in these pathways lead to defects in root development, such as shortened roots and furcation abnormalities. Advances in dental stem cells, biomaterials, and bioprinting show immense promise for bioengineered tooth root regeneration. However, replicating the developmental intricacies of odontogenesis has not been resolved in clinical treatment and remains a major challenge in this field. Ongoing research focusing on the mechanisms of root development, advanced biomaterials, and manufacturing techniques will enable next-generation biological root regeneration that restores the physiological structure and function of the tooth root. This review summarizes recent discoveries in the underlying mechanisms governing root ontogeny and discusses some recent key findings in developing of new biologically based dental therapies.

Count Me in, Count Me out: Regulation of the Tooth Number via Three Directional Developmental Patterns

Tooth number anomalies, including hyperdontia and hypodontia, are common congenital dental problems in the dental clinic. The precise number of teeth in a dentition is essential for proper speech, mastication, and aesthetics. Teeth are ectodermal organs that develop from the interaction of a thickened epithelium (dental placode) with the neural-crest-derived ectomesenchyme. There is extensive histological, molecular, and genetic evidence regarding how the tooth number is regulated in this serial process, but there is currently no universal classification for tooth number abnormalities. In this review, we propose a novel regulatory network for the tooth number based on the inherent dentition formation process. This network includes three intuitive directions: the development of a single tooth, the formation of a single dentition with elongation of the continual lamina, and tooth replacement with the development of the successional lamina. This article summarizes recent reports on early tooth development and provides an analytical framework to classify future relevant experiments.

Immunohistochemical expression of SOX2 in OKC and ameloblastoma: A comparative study

Introduction

Odontogenic, non-inflammatory maxillofacial cysts and tumours vary greatly in their ability to grow and cause local tissue destruction. Despite their common embryologic origin, the biologic mechanisms responsible for this diverse array of clinical behaviour are largely unknown. Unfortunately, even with accurate tissue diagnosis and appropriate surgical management, these tumours have relatively high recurrence rates. While this may be related to surgical technique, it may also be due to intrinsic tumour biology. SOX2 is differentially expressed in odontogenic cysts and tumours, which has an impact over patient prognosis. This could be related to their diverse cells of origin or stages of histogenesis. SOX2 is expressed in OKC and ameloblastoma, and in this study, we look forward to find altered levels and intensity of SOX2 in the above-mentioned lesions.

Aim and Objectives

To profile the expression of SOX2 in odontogenic keratocyst (OKC) and ameloblastomaTo compare the intensity of these lesions, analyse their intrinsic feature and predict their recurrence.

Material and Methods

Histopathologically diagnosed cases of OKC and ameloblastoma will be selected (n = 40). Paraffin-embedded, formalin-fixed sections of these lesions will be stained for SOX2 marker using a standard immunohistochemical technique. Positive control will be taken as oral squamous cell carcinoma and negative control will be taken as normal oral mucosa.

Results

A comparison between the stained cell types in odontogenic keratocyst and ameloblastoma revealed statistically significant differences. The immunoreactivity scores of SOX2 were analysed in both groups. The results indicated that 45% of OKC cases exhibited strongly positive reactivity, while 65% of ameloblastoma cases were negative. Statistical analysis demonstrated highly significant differences in the frequency of SOX2 expression between the two groups, with a higher frequency of negative expression in ameloblastoma.

Conclusion

Stem cell markers have been observed in these lesions, suggesting the acquisition of stem-like properties by tumour cells, which can affect patient prognosis. Specifically, the marker SOX2 shows differential expression in odontogenic cysts and tumours. High expression of SOX2 in OKC indicates the presence of stem cells with significant self-renewal and proliferative properties, potentially signifying neoplastic behaviour. In contrast, weak or absent expression of SOX2 in ameloblastoma suggests different molecular pathways involved in its neoplastic behaviour.

The Stem Cell Expression Profile of Odontogenic Tumors and Cysts: A Systematic Review and Meta-Analysis

BACKGROUND

Stem cells have been associated with self-renewing and plasticity and have been investigated in various odontogenic lesions in association with their pathogenesis and biological behavior. We aim to provide a systematic review of stem cell markers' expression in odontogenic tumors and cysts.

METHODS

The literature was searched through the MEDLINE/PubMed, EMBASE via OVID, Web of Science, and CINHAL via EBSCO databases for original studies evaluating stem cell markers' expression in different odontogenic tumors/cysts, or an odontogenic disease group and a control group. The studies' risk of bias (RoB) was assessed via a Joanna Briggs Institute Critical Appraisal Tool. Meta-analysis was conducted for markers evaluated in the same pair of odontogenic tumors/cysts in at least two studies.

RESULTS

29 studies reported the expression of stem cell markers, e.g., SOX2, OCT4, NANOG, CD44, ALDH1, BMI1, and CD105, in various odontogenic lesions, through immunohistochemistry/immunofluorescence, polymerase chain reaction, flow cytometry, microarrays, and RNA-sequencing. Low, moderate, and high RoBs were observed in seven, nine, and thirteen studies, respectively. Meta-analysis revealed a remarkable discriminative ability of SOX2 for ameloblastic carcinomas or odontogenic keratocysts over ameloblastomas.

CONCLUSION

Stem cells might be linked to the pathogenesis and clinical behavior of odontogenic pathologies and represent a potential target for future individualized therapies.