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

Immunohistochemical Expression of MDM2, Bcl-2, SATB2 and Ki-67 in Histological Variants of Unicystic Ameloblastoma

AIM

To characterize the immunohistochemical expression of MDM2, Bcl-2, SATB2 and Ki-67 in histological variants of unicystic ameloblastoma (UA).

METHODOLOGY

Following the ethical approval, forty (40) patients with unicystic ameloblastoma were retrieved from the archives and subjected to immunohistochemistry (IHC). Sociodemographic and clinical data were also retrieved. The results were entered into a Microsoft Excel spreadsheet and analyzed using SPSS software.

RESULTS

Human tooth germs, which served as the control, showed moderate expression of Bcl-2 and MDM2 with slight proliferative activity in ameloblasts and moderate expression of SATB2 in ectomesenchyme and odontoblasts. Luminal UA (Type 1) showed low Ki-67 index and negative to mild Bcl-2 and MDM2 expression, whilst Type 1.2 (luminal and intraluminal), Type 1.2.3 (luminal, intraluminal and mural), and Type 1.3 (luminal and mural), including the recurrent cases, showed moderate to intense expression with high mean Ki-67 index. The difference between the study groups was statistically significant (p value < 0.001). No expression of SATB2 was noted in any histological variant of UA. Furthermore, no significant differences were noted in age, gender, site and location between the groups.

CONCLUSION

In contrast to luminal variant of UA, mural±intraluminal variants and recurrent cases demonstrate higher expression of Bcl-2 and MDM2 with higher mean Ki-67 index. It may thus be prudent to provide aggressive treatment for cases, not just with mural follicles but also for the patients with intraluminal plexiform proliferation, to prevent recurrence and improve patient outcomes.

Title of the article: diagnostic markers for odontogenic tumors: an insight: a review

Odontogenic tumors are a group of tumors that originate from the tissues associated with tooth development and are classified into benign or malignant based on their behavior and characteristics. Tumor markers are substances that can be found in the blood, urine, or tissues of individuals with cancer. They are the substances produced either by tumor cells itself or by the body in response to tumor growth, can sometimes be used in the diagnosis, prognosis, and monitoring of various types of tumors. However, the use of tumor markers in odontogenic tumors is not as common as it is in other types of cancers, and their utility in this context is limited. Tumor markers are not the main tools for diagnosing cancer; instead, they serve as supplementary laboratory tests to aid in the diagnosis. Researchers continue to investigate potential biomarkers to improve our understanding of these tumors and their behavior. With this concept in mind, the objective of this study is to elucidate the key diagnostic markers essential for diagnosing odontogenic tumors.

Function and Therapeutic Potential of Non-Coding RNA in Ameloblastoma

Ameloblastoma (AB) is a common odontogenic tumor that develops in the mouth. Despite its benign nature, AB exhibits significant invasiveness leading to tumor metastasis and high postoperative recurrence rates. Studies have shown a relationship between the occurrence and development of various tumors and non-coding RNA (ncRNA). NcRNA, transcribed from the genomes of mammals and other complex organisms, are often products of alternative splicing and processing into smaller products. MicroRNA (miRNA), circular RNA (circRNA), and long non-coding RNA (lncRNA) are the main types of ncRNA. NcRNA play increasingly significant roles in the pathogenesis of human cancers, regulating their occurrence and progression as oncogenes or tumor suppressors. They are involved in tumor development and progression through alternative splicing of pre-mRNA, transcriptional regulation, mRNA stability, protein translation, and chromatin remodeling and modification. The importance of ncRNA in AB has received significant attention in recent years. However, the biological functions and mechanisms of ncRNA in AB remain largely unknown. In this review, we not only explore the functions and roles of ncRNA in AB, but also describe and envision their potential functional roles as biomarkers in AB diagnosis. In particular, we highlight the potential of miR-29a as a molecular marker for diagnosis and therapy. As promising novel therapeutic targets, the biological functions of ncRNA need further study, which is indispensable.

Immunohistochemical Expression of Ki-67 and p53 and Their Prognostic Role in Ameloblastoma: A Longitudinal Study

Objectives

Ameloblastoma, comprising approximately 11% of all odontogenic tumors, is a locally aggressive tumor with a high recurrence rate. This study aimed to assess the immunohistochemical expression of Ki-67 and p53 and their association with clinical and pathological factors among patients with ameloblastoma.

Methods

Retrospective follow-up data of patients histologically confirmed with ameloblastoma at Makerere College of Health Sciences in Kampala, Uganda from January 2012 to December 2018 were retrieved. Factors associated with Ki-67 and p53 immunohistochemical expression were determined using one-way one-way analysis of variance. Chi-square and Fisher's exact statistical tests were used to assess factors associated with recurrence. A two-tailed p < 0.05 was considered statistically significant.

Results

A total of 40 patients confirmed histologically with ameloblastoma were included in the analysis. The majority (62.5%) of cases were of the conventional type of ameloblastoma. The expressions of Ki-67 and p53 were 52.5% and 85.0%, respectively. Recurrence was found in 47.5% of patients and it was associated with conventional histological type (p=0.042), segmental resection (p < 0.001), tumor size (p < 0.001), and high p53 expression (p=0.041).

Conclusions

Almost half the cases in this study had recurrence. The immunohistochemical expression of p53 was significantly higher than that of Ki-67.

Prognostic value of the expression and localization of cell proliferation and apoptosis markers in unicystic ameloblastomas

The aim of this study was to verify whether the expression of cell proliferation and apoptosis markers in different types of unicystic ameloblastoma (UA) is associated with the location of neoplastic cells. Immunohistochemical study with a sample of 32 cases of UA, 11 cases of conventional ameloblastoma (CAM) and ten dental follicles (DF) cases was performed. Cell proliferation was assessed using Ki-67 status, and apoptosis by caspase-3 expression. Mural UA (MUA) showed a higher immunostaining of Ki-67 (p < 0.05) and a lower immunostaining of Caspase-3 (p < 0.05) compared with luminal and intraluminal subtypes of UA and CAM. The neoplastic cells of the MUA's cystic capsule showed a higher expression of Ki-67 protein (p < 0.0001) and a lower expression of Caspase-3 (p < 0.0001) compared with the lumen. DF showed lower Ki-67 and Caspase-3 immunostaining (p < 0.05) than neoplasms. The higher immunoexpression of Ki-67 and the lower immunoexpression of Caspase-3 in MUA, in the parenchyma cells within the cystic capsule, suggest an association between the biological behaviour and location of neoplastic cells in a tumour.

DNA content and clinicopathological features aid in distinguishing ameloblastic carcinoma from ameloblastoma

BACKGROUND

Ameloblastoma and ameloblastic carcinoma are epithelial odontogenic tumors that can be morphologically similar. In the present study, we evaluated the DNA content and Ki-67 index in the two tumors.

METHODS

The paraffin blocks of the tumors were selected to obtain sections for the immunohistochemical reactions and preparation of the cell suspension for acquisition in a flow cytometer. The Random Forest package of the R software was used to verify the contribution of each variable to classify lesions into ameloblastoma or ameloblastic carcinoma.

RESULTS

Thirty-two ameloblastoma and five ameloblastic carcinoma were included in the study. In our sample, we did not find statistically significant differences in Ki-67 labeling rates. A higher fraction of cells in 2c (G1) was correlated with the diagnosis of ameloblastoma, whereas higher rates of 5c-exceeding rate (5cER) were correlated with ameloblastic carcinoma. The Random Forest model highlighted histopathological findings and parameters of DNA ploidy study as important features for distinguishing ameloblastoma from ameloblastic carcinoma.

CONCLUSION

Our findings suggest that the parameters of the DNA ploidy study can be ancillary tools in the classification of ameloblastoma and ameloblastic carcinoma.

Valente FA. Ameloblastic carcinoma of the mandible: A case report

Ameloblastic carcinoma (AC) is a rare, primary epithelial odontogenic malignant neoplasm. It is the malignant counterpart of ameloblastoma. It comprises 1% of all cysts and tumours occurring in the jaws, arising from tissues associated with odontogenic epithelium. The objective of the present study was to describe a clinical case of a 63-year-old male with an enlargement in the mandible on the left side. Panoramic radiography revealed a radiolucent area with poorly defined borders, and an incisional biopsy was performed for the histopathological study using immunomarkers such as SOX2 and Ki-67. Ki-67 is considered a marker of cell proliferation, and SOX2 reportedly participates in the development of the ameloblastic epithelium lineage and is associated with a more aggressive clinical course. A final histopathological diagnosis of AC was given. Unfortunately, the patient died one week before surgical resection (the surgical treatment of choice for AC).

Immunoexpression of galectin-3 and its potential relation to hypoxia-inducible factor-1α in ameloblastomas

In tumor biology, hypoxia triggers signaling pathways that induce transcription of genes related to angiogenesis, metastasis, glucose metabolism and apoptosis. We investigated the expression of hypoxia related proteins, galectin-3 (Gal-3) and hypoxia-inducible factor-1α (HIF-1α), in conventional (CA) and unicystic ameloblastomas (UA). We applied immunohistochemistry for Gal-3 and HIF-1α to 72 cases of ameloblastoma: 59 cases of CA and 13 cases of unicystic UA. Immunoexpression was evaluated semiquantitatively. Gal-3 expression was observed in 40% of the cases: 23/59 CA and 6/13 UA. HIF-1α immunostaining was observed in 55% of cases: 36/59 CA and 4/13 UA. 19 CA and 2 UA were positive for both markers. Immunostaining was evident in the center of the tumor islands, which exhibited squamous metaplasia or cystic degeneration. The expression of Gal-3 and HIF-1α in ameloblastomas could be interpreted as a response to hypoxic stress. Co-expression of both proteins in CA may suggest a potential interaction that participates in the biological behavior of this ameloblastoma variant.

Elevated expression of minichromosome maintenance 3 indicates poor outcomes and promotes G1/S cell cycle progression, proliferation, migration and invasion in colorectal cancer

Background: The minichromosome maintenance (MCM) family, a core component of DNA replication, is involved in cell cycle process. Abnormal proliferation has been identified as a crucial process in the evolution of colorectal cancer (CRC). However, the roles of the MCM family in CRC remain largely unknown.

Methods: Here, the expression, prognostic significance and functions of the MCM family in CRC were systematically analyzed through a series of online databases including CCLE, Oncomine, HPA, cBioPortal and cancerSEA.

Results: We found all MCM family members were highly expressed in CRC, but only elevation of MCM3 expression was associated with poor prognosis of patients with CRC. Further in vitro and in vivo experiments were performed to examine the role of MCM3 in CRC. Analysis of CCLE database and qRT-PCR assay confirmed that MCM3 was overexpressed in CRC cell lines. Moreover, knockdown of MCM3 significantly suppressed transition of G1 to S phase in CRC cells. Furthermore, down-regulation of MCM3 inhibited CRC cell proliferation, migration, invasion and promoted apoptosis.

Conclusion: These findings reveal that MCM3 may function as an oncogene and a potential prognosis biomarker. Thus, the association between abnormal expression of MCM3 and the initiation of CRC deserves further exploration.

Diagnostic and prognostic value of MCM3 and its interacting proteins in hepatocellular carcinoma

Aberrant DNA replication is one of the driving forces behind oncogenesis. Furthermore, minichromosome maintenance complex component 3 (MCM3) serves an essential role in DNA replication. Therefore, in the present study, the diagnostic and prognostic value of MCM3 and its interacting proteins in hepatocellular carcinoma (HCC) were investigated. By utilizing The Cancer Genome Atlas (TCGA) database, global MCM3 mRNA levels were assessed in HCC and normal liver tissues. Its effects were further analyzed by reverse transcription-quantitative PCR (RT-qPCR), western blotting and immunohistochemistry in 78 paired HCC and adjacent tissues. Functional and pathway enrichment analyses were performed using the Search Tool for the Retrieval of Interacting Genes database. The expression levels of proteins that interact with MCM3 were also analyzed using the TCGA database and RT-qPCR. Finally, algorithms combining receiver operating characteristic (ROC) curves were constructed using binary logistic regression using the TCGA results. Increased MCM3 mRNA expression with high α-fetoprotein levels and advanced Edmondson-Steiner grade were found to be characteristic of HCC. Survival analysis revealed that high MCM3 expression was associated with poor outcomes in patients with HCC. In addition, MCM3 protein expression was associated with increased tumor invasion in HCC tissues. MCM3 and its interacting proteins were found to be primarily involved in DNA replication, cell cycle and a number of binding processes. Algorithms combining ROCs of MCM3 and its interacting proteins were found to have improved HCC diagnosis ability compared with MCM3 and other individual diagnostic markers. In conclusion, MCM3 appears to be a promising diagnostic biomarker for HCC. Additionally, the present study provides a basis for the multi-gene diagnosis of HCC using MCM3.

Cell kinetic markers in cutaneous squamous and basal cell carcinoma of the head and neck

Introduction

Proliferation markers play a significant role in the biologic behavior of tumors. Geminin is a known inhibitor of the cell cycle and DNA replication and has not been previously reported in cutaneous basal and squamous cell carcinomas of the head and neck.

Objectives

We aimed to investigate proliferation markers ki67, MCM2, and geminin in head and neck cutaneous basal and squamous cell carcinomas.

Methods

Forty cases of each tumor were immuostained with ki67, MCM2, and geminin followed by assessment of labeling indices (LIs). MCM2/ki67- and geminin/ki67-ratios were also determined; t-test was used for statistical analysis (p < 0.05).

Results

There was no significant difference in ki67 (p = 0.06) and MCM2 (p = 0.46) between cutaneous basal and squamous cell carcinomas; however, geminin LI was significantly higher in squamous cell carcinomas compared to cutaneous basal cell carcinomas (p < 0.001). Only geminin/ki67 showed a significant difference between the two tumors with the ratio showing significantly higher numbers in squamous cell carcinomas (p = 0.015).

Conclusions

Geminin could be regarded as an effective factor in the pathogenesis of head and neck cutaneous cutaneous basal cell carcinomas and squamous cell carcinomas and may be one of the responsible elements in the difference between the biologic behavior of these tumors.

Evaluation of B Cell Proliferation in vivo by EdU Incorporation Assay

Generation of antibodies is crucial for establishing enduring protection from invading pathogens, as well as for maintaining homeostasis with commensal bacteria at mucosal surfaces. Chronic exposure to microbiota- and dietary- derived antigens results in continuous production of antibody producing cells within the Peyer's patch germinal center structures. Recently, we have shown that B cells responding to gut-derived antigens colonize the subepithelial dome (SED) in Peyer's patches and rapidly proliferate independently of their relative BCR affinity. To evaluate B cell proliferation within different niches in Peyer's patches, we applied in vivo EdU incorporation assay as described in this protocol.

A Novel BCL-2 Inhibitor APG-2575 Exerts Synthetic Lethality With BTK or MDM2-p53 Inhibitor in Diffuse Large B-Cell Lymphoma

Despite therapeutic advances, the effective treatment for relapsed or refractory diffuse large B-cell lymphoma (DLBCL) remains a major clinical challenge. Evasion of apoptosis through upregulating antiapoptotic B-cell lymphoma-2 (BCL-2) family members and p53 inactivation, and abnormal activation of B-cell receptor signaling pathway are two important pathogenic factors for DLBCL. In this study, our aim is to explore a rational combination of BCL-2 inhibitor plus Bruton’s tyrosine kinase (BTK) blockade or p53 activation for treating DLBCL with the above characteristics. We demonstrated that a novel BCL-2 selective inhibitor APG-2575 effectively suppressed DLBCL with BCL-2 high expression via activating the mitochondrial apoptosis pathway. BTK inhibitor ibrutinib combined with BCL-2 inhibitors showed synergistic antitumor effect in DLBCL with mean expression of BCL-2 and myeloid cell leukemia-1 (MCL-1) through upregulating the expression level of BIM and modulating MCL-1 and p-Akt expression. For p53 wild-type DLBCL with high expression of BCL-2, APG-2575 showed strong synergic effect with mouse double minute 2 (MDM2)–p53 inhibitor APG-115 that can achieve potent antitumor effect and markedly prolong survival in animal models. Collectively, our data provide an effective and precise therapeutic strategy through rational combination of BCL-2 and BTK or MDM2–p53 inhibitors for DLBCL, which deserves further clinical investigation.

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.

Upregulation of microRNA‑194‑5p inhibits hypopharyngeal carcinoma cell proliferation, migration and invasion by targeting SMURF1 via the mTOR signaling pathway

Hypopharyngeal carcinoma (HPC) is an aggressive malignancy with the worst prognosis among all head and neck cancers. MicroRNAs (miRNAs) are involved in the development of many human cancers, and may function as oncogenes or tumor suppressors. The present study aimed to evaluate the effects of miRNA (miR)-194-5p on the proliferation and invasion of HPC cells and to identify the potential regulatory mechanism. First, miR-194-5p and Smad ubiquitin regulatory factor 1 (SMURF1) expression levels were examined in HPC tissues. Subsequently, to explore the effects of miR-194-5p on SMURF1, a dual-luciferase reporter gene assay was performed to verify the target relationship. To define the role of miR-194-5p in HPC progression, miR-194-5p upregulation and depletion were used to evaluate its effects on cell viability, invasion and migration. SMURF1 silencing and rapamycin [an inhibitor of the mammalian target of rapamycin (mTOR) signaling pathway] treatment were also used to analyze the regulatory mechanism in HPC. Finally, tumor growth was assessed in xenografted tumors in nude mice. SMURF1 was demonstrated to be highly expressed, whereas miR-194-5p was poorly expressed in HPC tissues; SMURF1 was identified as a target gene of miR-194-5p. FaDu hypopharyngeal squamous cell carcinoma cells treated with miR-194-5p mimics exhibited decreased viability, invasion and migration. The results indicated that miR-194-5p may inactivate the mTOR signaling pathway by targeting SMURF1. In addition, the in vivo experiments further verified these regulatory effects. These data suggested that miR-194-5p-targeted SMURF1 inhibition may be involved in the disruption of HPC progression through the repression of the mTOR signaling pathway.

Comparative Study of the Minichromosome Maintenance Proteins Complex (MCM 4/5/6) in Ameloblastoma and Unicystic Ameloblastoma

INTRODUCTION

Solid/conventional ameloblastoma (AM) and unicystic ameloblastoma (UAM) are the most frequent benign epithelial odontogenic tumors located in the maxillary region, and their treatment usually consists of extensive surgical resection. Therefore, it is relevant to study molecular markers to better understand the biological behavior of these tumors. The aim of this study was to describe and compare the expression of proteins related to cellular proliferation: Ki-67 and MCM4-6 complex.

MATERIALS AND METHODS

An immunohistochemistry technique was performed, with antibodies against Ki-67, MCM4, MCM5, and MCM6, in 10 AM and 10 UAM tumors. The results were quantified using label index and analyzed statistically.

RESULTS

AM and UAM had greater expression of MCM6, followed by MCM5, MCM4, and Ki-67 ( P < .05). Immunoexpression of Ki-67 and MCM5 was exclusively nuclear, whereas the expression of MCM4 and MCM6 was nuclear and cytoplasmic.

CONCLUSION

The results suggest that MCM5 is a trustable cell proliferation marker with higher sensitivity compared with Ki-67 and may be useful to predict the biological behavior of AM and UAM. Despite this, further studies are necessary, including a correlation with clinical parameters to confirm these findings.

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.

Minichromosome maintenance protein 2 and 3 promote osteosarcoma progression via DHX9 and predict poor patient prognosis

A label free quantitative proteomic approach (SWATH™ experiment) was performed to identify tumor-associated nuclear proteins that are differentially expressed between osteosarcoma cells and osteoblast cells. By functional screening, minichromosome maintenance protein 2 (MCM2) and minichromosome maintenance protein 3 (MCM3) were found to be related to osteosarcoma cell growth. Here, we show that knockdown of MCM2 or MCM3 inhibits osteosarcoma growth in vitro and in vivo. In co-immunoprecipitation and co-localization experiments, MCM2 and MCM3 were found to interact with DExH-box helicase 9 (DHX9) in osteosarcoma cells. A rescue study showed that the decreased growth of osteosarcoma cells by MCM2 or MCM3 knockdown was reversed by DHX9 overexpression, indicating that MCM2 and MCM3 activity was DHX9-dependent. In addition, the depletion of DHX9 hindered osteosarcoma cell proliferation. Notably, MCM2 and MCM3 expression levels were positively correlated with the DHX9 expression level in tumor samples and were associated with a poor prognosis in patients with osteosarcoma. Taken together, these results suggest that the MCM2/MCM3–DHX9 axis has an important role in osteosarcoma progression.

Ameloblastoma RNA profiling uncovers a distinct non-coding RNA signature

Ameloblastoma of the jaws remains the top difficult to treat odontogenic tumour and has a high recurrence rate. New evidence suggests that non-coding RNAs (ncRNAs) play a critical role in tumourgenesis and prognosis of cancer. However, ameloblastoma ncRNA expression data is lacking. Here we present the first report of ameloblastoma ncRNA signatures. A total of 95 ameloblastoma cases and a global array transcriptome technology covering > 285.000 full-length transcripts were used in this two-step analysis. The analysis first identified in a test cohort 31 upregulated ameloblastoma-associated ncRNAs accompanied by signalling pathways of cancer, spliceosome, mRNA surveillance and Wnt. Further validation in an independent cohort points out the long non-coding (lncRNAs) and small nucleolar RNA (snoRNAs): LINC340, SNORD116-25, SNORA11, SNORA21, SNORA47 and SNORA65 as a distinct ncRNA signature of ameloblastoma. Importantly, the presence of these ncRNAs was independent of BRAF-V600E and SMO-L412F mutations, histology type or tumour location, but was positively correlated with the tumour size. Taken together, this study shows a systematic investigation of ncRNA expression of ameloblastoma, and illuminates new diagnostic and therapeutic targets for this invasive odontogenic tumour.

Expression of parathyroid hormone related protein (PTHRP) in ameloblastomas

BACKGROUND

Presence of parathyroid hormone related protein (PTHrP) might suggest that ameloblastomas recapitulate features of the enamel epithelium and induce bone resorption, which would facilitate their growth and local invasion. The aim of this study was to determine the expression of PTHrP in ameloblastomas.

MATERIAL AND METHODS

An observational research study was designed including 39 cases of histologically diagnosed ameloblastomas (39 out of 42 patients gave consent for the use of their medical records and all data required for this study). Gender, age, tumor location, histological type and subtype of the tumor were recorded and PTHrP expression was determined by indirect immunohistochemistry using monoclonal anti-human PTHrP (1D1 / Santa Cruz Biotechnology). Protein expression and intensity were evaluated under light microscope and finally data recorded and statistically analyzed. This research was approved by the Caracas West General Hospital review board.

RESULTS

39 cases of ameloblastomas were evenly distributed between genders (49% male and 51% female) with a mean age of 33 ± 3.53 years, mainly affecting the posterior mandible. 20 cases (51.28%) showed positive cytoplasmic immunoreactivity to PTHrP. 8 out of 15 cases of solid/multicystic ameloblastomas and 12 out of 23 cases of unicystic ameloblastomas were PTHrP positive. Intense expression of PTHrP was observed in 4 unicystic ameloblastomas (all luminal subtype) and in 5 cases of conventional ameloblastomas.

CONCLUSIONS

In the present study PTHrP expression in solid multicystic and unicystic ameloblastoma suggests its possible function in the biological behavior of the tumor. More studies are needed in order to determine the possible role of this protein related to bone invasion processes. Key words:Parathyroid hormone related protein, PTHrP, ameloblastoma, bone.

Immunohistochemical expression of osteonectin, matrix metalloproteinases-9 and Ki-67 in ameloblastoma

Background:

Ameloblastoma (AM) is a benign odontogenic neoplasm characterized by local invasiveness and recurrence. We have evaluated the immunohistochemical expressions of osteonectin (ON), matrix metalloproteinase-9 (MMP-9) and Ki-67 in AM to understand the biologic behavior of this neoplasm.

Aim:

The aim of this study is to evaluate the expression of ON, MMP-9 and Ki-67 in AM.

Materials and Methods:

The study sample included archival tissues embedded in paraffin blocks histopathologically diagnosed as AM (20 cases). Three serial sections of each tissue specimen were stained separately with ON, MMP-9 and Ki-67 (immunohistochemistry stain) and evaluated. The data were analyzed using Spearman rank correlation test.

Results:

All AM cases 20/20 (100%) exhibited positive immunostaining for ON, MMP-9 and Ki-67.

Conclusion:

Increased expression of ON, MMP-9 and Ki-67 in AM indicates that these molecules might play a role in the regulation and aggressive nature of this neoplasm.

Comparison between Manual and Automated Methods for Ki-67 Immunoexpression Quantification in Ameloblastomas

Ameloblastoma is a common and unpredictable odontogenic tumor with high relapse rates. Several studies assessing the proliferative capacity of these neoplasms have been published, mainly using the protein Ki-67. Cell counts must be completed to determine the cell proliferation rate. Multiple methods have been developed for this purpose. The most widely used method is the labeling index, which has undergone changes over time to better facilitate cell counting. Here, we compared manual cell counting methods with automated cell counting (ImmunoRatio) to determine the relative effectiveness of these methods. The results suggest that ImmunoRatio, a free software tool, may be highly advantageous and provide results similar to manual cell counting methods when used with the appropriate calibration. However, ImmunoRatio has flaws that may affect the labeling index results. Therefore, this automated cell counting method must be supplemented with manual cell counting methods.