CD1a-positive Langerhans cells and their relationship with E-cadherin in ameloblastomas and keratocystic odontogenic tumors

CD1a is not effective in distinguishing calcifying epithelial odontogenic tumors from amyloid-rich central odontogenic fibroma

OBJECTIVE

Differential diagnosis between the non-calcifying variant of calcifying epithelial odontogenic tumor (NCLC-CEOT) and amyloid-rich central odontogenic fibroma (AR-COdF) has become a debate, particularly regarding the frequency of CD1a positivity in both entities. This has led to the growing consensus that CD1a-positive staining in AR-NC lesions confirms the diagnosis of AR-COdF. Here, we assess the validity of this consensus.

STUDY DESIGN

We collected the data of a case series of histopathologically distinct CEOTs, NCLC-CEOTs, and COdFs and stained them for CD1a and amyloid. Of the 9 CEOTs and NCLC-CEOTs, we diagnosed 4 as classic, 3 as associated with a dentigerous cyst, and 2 as combined CEOT/adenomatoid odontogenic tumors. Of the 9 COdFs, we diagnosed 3 as epithelial poor, 3 as epithelial rich (lacking amyloid), 2 as hyalinized with amyloid, and 1 as hyalinized without amyloid and assessed the staining results.

RESULTS

Of the 9 CEOTs and NCLC-CEOTs, 7 stained positively for CD1a, 5 diffusely and 2 focally. Notably, 2 classic NCLC-CEOTs stained strongly CD1a positive. All 3 of the epithelial-poor COdFs were predictably CD1a negative. Of the 6 remaining COdFs, 2 were CD1a positive, 1 hyalinized-with-amyloid COdF diffusely and 1 epithelial-rich-without amyloid focally.

CONCLUSIONS

CD1a positivity, which occurs in classic CEOT and NCLC-CEOT, does not help distinguish between NCLC-CEOT and AR-COdF and is inconsistent in all AR-COdFs. The diagnosis of CEOT and AR-COdF should be guided by appropriate histopathologic criteria irrespective of CD1a staining or the presence of amyloid or calcifications.

Non-Calcifying/Langerhans Cell-Rich Calcifying Epithelial Odontogenic Tumour: A Critical Review of the Rare and Distinctive Entity

BACKGROUND

The study aims to analyse the non-calcifying/Langerhans cell rich (NCLC) subtype of calcifying epithelial odontogenic tumour (CEOT).  METHOD: The features of cases of the NCLC subtype of CEOT noted in the English literature by PubMed as well as 3 new cases were reviewed.

RESULTS

Overall, twenty-one cases were noted. Many were women in the fourth to sixth decades (male-to-female ratio =1 to 2). Radiologically, the lesion is often unilocular with resorption of the affected teeth. Nineteen of the 21 cases occurred in the maxilla, especially the anterior portion. On pathological examination, epithelial cells are noted in non-calcifying amyloid-rich fibrous stroma. The main differential diagnosis is the amyloid subtype of central odontogenic fibroma. Immunohistochemical studies revealed the tumour epithelial cells were positive for cytokeratins and p63 and contained CD1a, S-100, and langerin-positive Langerhans cells. On a median follow-up of 2 years, one patient had a recurrence one year after curettage.

CONCLUSION

The NCLC subtype of CEOT is unique as it contains significant numbers of Langerhans cells and has clinicopathological features distinctive from classic CEOT.

Immunohistochemical expression of Ki-67 and Glypican-3 to distinguish aggressive from nonaggressive benign odontogenic tumors

Background

The benign neoplasms are normally slow growing, indolent with no invasive potential. However, there exist a few locally aggressive benign odontogenic tumors that have a tendency to invade and deform the surrounding structures. The exact reason for the aggressiveness of these benign neoplasms remained an enigma. Their biology and clinical expression can often be destructive and ominous. An appropriate treatment protocol needs to be followed to combat the high recurrence rate and aggressiveness of these entities. Aggressive and noniaggressive epithelial odontogenic tumors were analyzed immunohistochemically with Ki-67 and glypican 3 (GPC3).

Materials and Methods

Fifty-nine cases of tumors were divided into aggressive odontogenic tumors (20 solid ameloblastomas, four unicystic ameloblastoma, and 28 keratocystic odontogenic tumors) and nonaggressive odontogenic tumors (five adenomatoid odontogenic tumors and two calcifying cystic odontogenic itumors).

Results

Statistical analysis using Pearson correlation showed Ki-67 to be a better marker for differentiating aggressive from nonaggressive odontogenic tumor as compared to GPC3 (P < 0.001, highly significant), whereas among aggressive tumors, GPC3 turned out to be more useful as compared to Ki-67 (P < 0.001, highly significant).

Conclusion

The present study provides an insight into the different biological behavior of odontogenic tumors, which can thus be helpful in determining the therapy strategies for more aggressive odontogenic tumors.

The immunohistochemical profile of basal cell nevus syndrome-associated and sporadic odontogenic keratocysts: a systematic review and meta-analysis

OBJECTIVES

To provide a systematic review of the literature on studies comparing the immunoprofile of nevoid basal cell carcinoma syndrome (BCNS)-associated and sporadic odontogenic keratocysts (OKCs), in order to identify markers that could accurately distinguish the two OKC subtypes.

MATERIALS AND METHODS

We searched MEDLINE/Pubmed, Web of Science, EMBASE via OVID, and grey literature for publications until December 28th, 2019, that compared the immunohistochemical expression of the two OKC subtypes. The studies were qualitatively assessed using the Critical Appraisal Tool for Case Series (Joana Briggs Institute). Sensitivity and specificity, positive and negative likelihood ratio, diagnostic odds ratio and area under the curve, and pooled estimates were calculated, using a random-effects model.

RESULTS

Seventy-one studies were qualitatively analyzed; 61 markers were evaluated in one study and 32 in ≥ 2 studies. Twenty-five studies reported differential expression of 29 markers in the form of higher number of positive cells or greater staining intensity usually in BCNS-associated OKCs. Meta-analysis for bcl-2, Cyclin D1, CD56, CK18, p53, and PCNA showed that none of those markers is distinguishable between BCNS-associated and sporadic OKCs, in a 95% confidence interval. The risk of bias was high in 34 studies, moderate in 22, and low in 15.

CONCLUSIONS

The present systematic review and meta-analysis uncovered that, although several immunohistochemical markers might characterize the OKC phenotype, they cannot discriminate between the BCNS-associated and sporadic OKCs.

CLINICAL RELEVANCE

This study highlighted the requirement for additional screening for markers by immunohistochemistry, preferentially coupled to alternative diagnostic applications such as genomics technologies.

Relationship between mast cells and E-cadherin in odontogenic keratocysts and radicular cysts

OBJECTIVE

This study aimed to evaluate tryptase and E-cadherin protein expression in odontogenic keratocysts (OKCs) and radicular cysts (RCs) and their relationship with lesion size.

MATERIALS AND METHODS

Thirty OKC and 30 RC cases were analyzed by immunohistochemistry. Tryptase expression was quantitatively assessed using the quantification of mast cells, and expression of E-cadherin was semi-quantitatively analyzed estimating the proportion of positive cells: 1 = less than 25% of immunopositive cells; 2 = 26 to 50% of immunopositive cells; 3 = 51 to 75% of immunopositive cells; 4 = more than 75% of immunopositive cells. Data on cystic lesion sizes were obtained from patients' clinical files, based on previous radiographic exams, and the lesions were categorized into three groups: group 1 (< 2 to 2 cm); group 2 (> 2 to 4 cm), and group 3 (> 4 cm).

RESULTS

Higher mast cell means were found for RCs, with the predominance of degranulated mast cells in both OKCs and RCs (p = 0.082). Concerning the epithelial component, a higher concentration of degranulated mast cells was detected in RCs (p = 0.000). Regarding connective tissue, degranulated mast cells were more evident in OKCs (p = 0.762). A negative correlation was observed between E-cadherin expression and total number of mast cells (p = 0.011), degranulated mast cells (p = 0.040), and degranulated mast cells in both superficial (p = 0.035) and deep connective tissues (p = 0.009). Concerning lesion size, a negative correlation with total number of mast cells (p = 0.016) and number of degranulated mast cells (p = 0.049) was observed, both in the epithelial components. Herein, the larger the lesion size, the lower the number of degranulated mast cells in the epithelium (r = - 0.271; p = 0.49), suggesting that these cells play a role in the initial cystic expansion phase.

CONCLUSION

The higher expression of tryptase in degranulated mast cells was linked to a lower expression of E-cadherin, which may be related to a change in the epithelial permeability in these lesions, contributing to increased cystic content and lesion growth.

CLINICAL RELEVANCE

Evidence of the relationship between mast cells and E-cadherin in the growth of odontogenic cysts was studied.

Langerhans cells in 60 odontogenic keratocysts

BACKGROUND/PURPOSE

Langerhans cells (LCs) are antigen-presenting cells. This study mainly evaluated the LC counts in 60 odontogenic keratocysts (OKCs).

MATERIALS AND METHODS

The CD1a-positive LC numbers in the lining epithelia and subepithelial connective tissues were counted at 60 OKC sites without inflammation, 39 OKC sites with mild/moderate inflammation, and 13 OKC sites with severe inflammation from 60 OKC specimens.

RESULTS

The mean CD1a-positive LC counts in the lining epithelia and subepithelial connective tissues increased significantly from no inflammation (0.5 ± 0.4 and 0.2 ± 0.3 cell/high-power field or HPF, respectively) through mild/moderate inflammation (5.3 ± 2.5 and 2.5 ± 2.7 cells/HPF, respectively) to severe inflammation OKC sites (12.7 ± 5.6 and 9.3 ± 7.2 cells/HPF, respectively; all P-values < 0.001). OKC sites with inflammation had thicker lining epithelia than those without inflammation. Moreover, the mean CD1a-positive LC counts in the lining epithelia and subepithelial connective tissues of OKCs were significantly higher in the thicker lining epithelium (>100 μm) group (6.8 ± 5.1 and 3.7 ± 4.9 cells/HPF, respectively) than in the thinner lining epithelium (≦100 μm) group (1.0 ± 1.7 and 0.8 ± 2.5 cell/HPF, respectively; both P-values < 0.001).

CONCLUSION

There is a significant association of inflammation grade with the number of LCs in OKCs. The scarce LCs in the lining epithelia of OKCs without inflammation suggests the loss of immunosurveillance ability against the OKC lining epithelial cells; this can explain why OKCs have aggressive clinical behavior, a great growth potential, and a high recurrence rate.

Significant association of inflammation grade with the number of Langerhans cells in odontogenic keratocysts

BACKGROUND/PURPOSE

Langerhans cells (LCs) are antigen-presenting cells. This study assessed the LC counts in odontogenic keratocysts (OKCs).

METHODS

The LC numbers in the lining epithelia and subepithelial connective tissues were counted at 60 OKC sites without inflammation, 39 OKC sites with mild/moderate inflammation, and 13 OKC sites with severe inflammation from 60 OKC specimens immunostained with anti-S100 antibodies.

RESULTS

The mean LC counts in the lining epithelia and subepithelial connective tissues increased significantly from no inflammation (0.5 ± 0.4 and 0.7 ± 0.6 cell/high-power field or HPF, respectively) through mild/moderate inflammation (5.9 ± 2.7 and 5.0 ± 3.5 cells/HPF, respectively) to severe inflammation OKC sites (14.7 ± 5.3 and 13.3 ± 6.8 cells/HPF, respectively; all P-values < 0.001). OKC sites with inflammation had thicker lining epithelia than those without inflammation. Moreover, the mean LC counts in the lining epithelia and subepithelial connective tissues of OKCs were significantly higher in the thicker lining epithelium (>100 μm) group (7.7 ± 5.6 and 6.5 ± 5.8 cells/HPF, respectively) than in the thinner lining epithelium (≦ 100 μm) group (1.0 ± 2.0 and 1.4 ± 2.6 cells/HPF, respectively; both P-values < 0.001).

CONCLUSION

A significant association of inflammation grade with the number of LCs in OKCs is found. The paucity of finding LCs in the lining epithelia of OKCs without inflammation indicates the loss of immunosurveillance ability against the OKC lining epithelial cells; this can explain why OKCs have aggressive clinical behavior, a great growth potential, and a high recurrence rate.

Glypican-3 distinguishes aggressive from non-aggressive odontogenic tumors: a preliminary study

BACKGROUND

Glypican-3 is a cell surface proteoglycan that is found in embrionary tissues, and there are no studies investigating this protein in odontogenic tumor. Thus, the aim of this study was to investigate glypican-3 in a series of aggressive and non-aggressive odontogenic tumors.

METHODS

Fifty-nine cases of tumors were divided into aggressive odontogenic tumors (20 solid ameloblastomas, four unicystic ameloblastoma, 28 KOTs including five associated with Gorlin-Goltz syndrome) and non-aggressive odontogenic tumors (five adenomatoid odontogenic tumors and two calcifying cystic odontogenic tumors) and analyzed for glypican-3 using immunohistochemistry.

RESULTS

Glypican-3 was observed in seven solid ameloblastoma and eighteen keratocystic odontogenic tumors including three of the five syndromic cases, but there was no significant difference between syndromic and sporadic cases (P > 0.05; Fisher's exact Test). All cases of unicystic ameloblastoma (n = 4), adenomatoid odontogenic tumor (n = 5), and calcifying cystic odontogenic tumor (n = 2) were negative.

CONCLUSIONS

This provided insights into the presence of glypican-3 in odontogenic tumors. This protein distinguished aggressive from non-aggressive odontogenic tumors.

Kallikrein 4 and matrix metalloproteinase-20 immunoexpression in malignant, benign and infiltrative odontogenic tumors

CONTEXT

Matrix metalloproteinase-20 (MMP20) (enamelysin) and kallikrein 4 (KLK4) are enzymes secreted by ameloblasts that play an important role in enamel matrix degradation during amelogenesis. However, studies have shown that neoplastic cells can produce such enzymes, which may affect the tumor infiltrative and metastatic behaviors.

AIMS

The aim of this study is to assess the biological role of MMP20 and KLK4 in odontogenic tumors.

MATERIALS AND METHODS

The enzymes were analyzed immunohistochemically in ameloblastoma, adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor, keratocystic odontogenic tumor with or without recurrence and odontogenic carcinoma.

STATISTICAL ANALYSIS USED

Clinicopathological parameters were statistically correlated with protein expression using the Fisher's exact test. Kruskal-Wallis and Wilcoxon-independent methods were used to evaluate the differences in median values.

RESULTS

Positive Immunoexpression was detected in all benign lesions, with a prevalence of 75-100% immunolabeled cells. Patients were predominantly young, Caucasian, female, with slow-growing tumors located in the mandible causing asymptomatic swelling. No KLK4 expression was seen in carcinomas, and the amount of MMP20-positive cells varied between 20% and 80%. Rapid evolution, recurrence and age >60 years characterized the malignant nature of these lesions.

CONCLUSIONS

Data showed that KLK4 and MMP20 enzymes may not be crucial to tumoral infiltrative capacity, especially in malignant tumors, considering the diversity and peculiarity of these lesions. The significant immunoexpression in benign lesions, remarkably in AOT, is likely associated with differentiated tumor cells that can produce and degrade enamel matrix-like substances. This would be expected since the histogenesis of odontogenic tumors commonly comes from epithelium that recently performed a secretory activity in tooth formation.

E-cadherin regulators are differentially expressed in the epithelium and stroma of keratocystic odontogenic tumors

BACKGROUND

The epithelial-mesenchymal transition (EMT) is the process where cells lose their epithelial features and acquire properties of typical mesenchymal cells. The dissociation of tumor cells due to changes in cell-cell adhesion is one of the key principles of tumor invasion and EMT. Thus, the knowledge of the molecular features of EMT in keratocyst odontogenic tumor (KOT) can provide useful markers to aid in the diagnosis and prognosis and perhaps contribute to an alternative therapeutic approach as it shows an aggressive clinical behavior and high recurrence rates. This study aimed to evaluate the EMT in KOT by the immunoexpression of E-cadherin, N-cadherin, Snail, and Slug and comparing to radicular cysts and dental follicles.

METHODS

Thirty-two KOTs, 15 radicular cysts, and 08 dental follicles were used for immunohistochemistry, evaluating the extent, intensity, labeling pattern, cellular compartment in the epithelium and stroma, and the presence of inflammation.

RESULTS

E-cadherin was preserved in most cases of keratocystic odontogenic tumor. N-cadherin was increased in the tumor epithelium, a result that was positively correlated with the heterogeneous and nuclear immunoexpression of Slug in the epithelium; Slug also correlated with high Snail immunoexpression. N-cadherin was positively correlated with Slug in the stroma of keratocystic odontogenic tumors.

CONCLUSIONS

The high immunoexpression of Snail and nuclear Slug in keratocystic odontogenic tumors suggests these proteins as transcription factors without necessarily participating in 'cadherin switching'. However, the knowledge of their induction of the epithelial-mesenchymal transition in odontogenic tumors is still limited.

RANK, RANKL, and OPG in recurrent solid/multicystic ameloblastoma: their distribution patterns and biologic significance

OBJECTIVES

To determine the distribution patterns of bone resorption regulators, receptor activator of nuclear factor κ-B (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in recurrent ameloblastoma (RAs) and to clarify their impact on the biologic behavior of these neoplasms.

MATERIALS AND METHODS

Fifteen paraffin-embedded RA cases were subjected to immunohistochemistry for expression of RANK, RANKL, and OPG.

RESULTS

The RANK-RANKL-OPG triad was heterogeneously detected in RA samples. RANK, essential for osteoclast differentiation, was strongly expressed in tumoral epithelium. Conversely, RANKL, an osteoclast activator, was markedly underexpressed, and protein localization was predominantly stromal. OPG, an osteoclastogenesis inhibitory factor, was detected in neoplastic epithelium more than in stroma, suggesting functional inactivation of RANKL. Most RA (n = 12/15; 80%) exhibited a bimolecular spatial expression pattern, the most common being RANK-positive/OPG-positive (n = 8/15; 53.3%). All three proteins showed no significant correlation with the clinical/histopathologic parameters in RA patients (P > .05).

CONCLUSIONS

The RANK(+)/RANKL(low/-)/OPG(+) phenotype observed in RA suggests an altered local bone metabolism characterized by low bone resorptive activity in these recurrent tumors.