Mast cells and T-lymphocytes in juvenile angiofibromas

Electron microscopy of juvenile nasopharyngeal angiofibroma: clinical and histopathological correlates

BACKGROUND

The histological and electron-microscopic (EM) characteristics of juvenile nasopharyngeal angiofibroma (JNA) have been described but no study has compared them with one another or with clinical features. The objective is to compare ultrastructural characteristics of JNA with clinical parameters.

METHODS

This prospective study included histology of 21 samples of which only 13 underwent transmission-EM. Four clinical parameters (age, duration, epistaxis, recurrence), three radiological-staging, 13 histological and 15 EM characteristics were considered. A descriptive analysis for association of these characteristics and also with clinical parameters was attempted. Furthermore statistical analysis of clinical and radiological categories with respect to frequencies of ultrastructural characteristics was also undertaken.

RESULTS

Dense-intranuclear-inclusions (DNI) and peripheral-nuclear-irregularities were universally encountered while other very prominent features were nuclear-blebs-and-pockets, myoid-features, thin-vessel-wall (TnVW), irregular-vascular-contour (IVC) and fibrous-stroma (FS). Statistical significance was obtained between recurrence with histology (p = 0.04) and Fisch staging with EM (p = 0.001). While muscle-in-vessel-wall, thick-vessel-wall, mast-cells, stellate-stromal-cells and cellular-stroma predominated in recurrent cases, the upfront disease showed predominance of scar-like-stroma, fusiform-stromal-cells, IVC, TnVW, FS, organised-collagen-bundles and less-cellular-stroma. A very unique Rod-like-structures were appreciated in the cytoplasm of the fibroblast for the first time.

CONCLUSIONS

While histological parameters of recurrence need further validation, a larger sample may better define histopathological surrogate for predicting intracellular dynamics that may further correlate with underlying cellular stresses. Hence an 'ultrastructural staging' may better customise treatment protocol and prognosis. Furthermore 'characteristic' unique rods need to be further investigated along with validation of viral aetiology for DNI.

Tissue microarray analysis reveals that cofilin expression is a poor prognostic factor in juvenile nasopharyngeal angiofibroma

BACKGROUND

Juvenile nasopharyngeal angiofibroma (JNA) has a high recurrence rate after surgery. Cofilin overexpression is associated with increased tumor cell metastasis, and progression of various human cancers. However, studies on cofilin expression in JNA are rare. The purpose of this study was to investigate the expression and localization of cofilin in a tissue microarray (TMA) of JNA specimens. In addition, we also analyzed its correlation with clinicopathological features and recurrence.

METHODS

Immunohistochemistry was performed to detect cofilin expression in a TMA of samples from 70 JNA patients and 10 control subjects. The association between clinicopathological variables and cofilin immunostaining was analyzed using Pearson's chi-square test. Kaplan-Meier survival analysis was used to calculate the disease-free survival rate, and investigate the effect of cofilin expression on time to recurrence (TTR) in JNA patients. The Cox regression model was used for multivariate survival analysis.

RESULTS

Cofilin was detected in irregular smooth muscle cells, pericytes, less differentiated stromal cells, and plump cells, but not in inactive fibroblasts and mature vascular endothelial cells of JNA specimens. The presence of cofilin in JNA was correlated with tumor stage (p = 0.012) and volume of intraoperative hemorrhage (p < 0.001). JNA patients with high cofilin expression had a higher recurrence rate than those with low cofilin expression (p = 0.012). Cofilin expression and patient's age were significant predictors of TTR, and cofilin was a better predictor for disease recurrence (area under the receiver operating curve [AUROC; 0.711; p = 0.005) than other clinicopathological features.

CONCLUSION

Cofilin is an independent prognostic marker for JNA patients who have undergone surgical treatment and may represent a novel therapeutic target for extensive JNA.

The Genetic and Molecular Determinants of Juvenile Nasopharyngeal Angiofibroma: A Systematic Review

Objective:

Juvenile nasopharyngeal angiofibroma (JNA) is a rare vascular tumor of unknown etiology. Studies investigating the molecular and genetic determinants of JNA are limited by small sample size and inconsistent approaches. The purpose of this study is to examine all eligible JNA studies in aggregate, applying qualitative analysis to highlight areas of particular relevance, including potential targets for therapeutic intervention.

Methods:

The PubMed, MEDLINE, Embase, Web of Science, Cochrane, and CINAHL databases were screened with inclusion and exclusion criteria applied to all citations. Manuscripts investigating the genetic determinants, histopathogenesis, and heritability of juvenile nasopharyngeal angiofibroma were included. Non-English studies, case reports, and articles focusing on clinical management without original data were excluded. Full text articles were obtained. A qualitative synthesis of data was performed.

Results:

A total of 59 articles met criteria for inclusion. These were divided into 6 categories based on the primary topic or target discussed, (1) steroid hormone receptors, (2) chromosomal abnormalities, (3) growth factors, (4) genetic targets, (5) molecular targets, (6) Wnt cell signaling, and (7) studies that overlapped multiple of the aforementioned categories. Although relatively low n values prevent definitive conclusions to be drawn, a predominance of certain molecular targets such as vascular endothelial growth factor (VEGF) and Wnt/β-catenin pathway intermediaries is apparent.

Conclusions:

Although the etiology of JNA remains elusive, contemporary molecular genetic investigation holds promise for risk stratification and could form the basis of a modernized staging system. A multicenter clinical registry and linked tissue bank would further promote the search for JNA specific biomarkers.

Variable expression of molecular markers in juvenile nasopharyngeal angiofibroma

Background:

Molecular categorisation may explain the wide variation in the clinical characteristics of juvenile nasopharyngeal angiofibroma.

Methods:

Variations in molecular markers in juvenile nasopharyngeal angiofibroma in an Indian population were investigated and compared with global reports.

Results:

Variable molecular marker expression was demonstrated at the regional and global levels. A wide variation in molecular characteristics is evident. Molecular data have been reported for only 11 countries, indicating a clear geographical bias. Only 58 markers have been studied, and most are yet to be validated.

Conclusion:

Research into the molecular epidemiology of juvenile nasopharyngeal angiofibroma is still in its infancy. Although the molecular variation is not well understood, data obtained so far have prompted important research questions. Hence, multicentre collaborative molecular studies are needed to establish the aetiopathogenesis and establish molecular surrogates for clinical characteristics.

Juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma (JNA) is a rare benign tumor arising predominantly in the nasopharynx of adolescent males. It is an aggressive neoplasm and shows a propensity for destructive local spread often extending to the base of the skull and into the cranium. Clinically, however, it is obscure with painless, progressive unilateral nasal obstruction being the common presenting symptom with or without epistaxis and rhinorrhea. Diagnosis of JNA is made by complete history, clinical examination, radiography, nasal endoscopy and by using specialized imaging techniques such as arteriography, computer tomography and magnetic resonance imaging. Histopathology reveals a fibrocellular stroma with spindle cells and haphazard arrangement of collagen interspersed with an irregular vascular pattern. A case report of JNA with rare intra-oral manifestation in a 17-year-old male patient is presented in the article. JNA being an aggressive tumor may recur posttreatment. Thus, early diagnosis, accurate staging, and adequate treatment are essential in the management of this lesion.

Identification of CTNNB1 mutations, CTNNB1 amplifications, and an Axin2 splice variant in juvenile angiofibromas

Juvenile angiofibromas (JAs) are benign fibro-vascular tumors occurring nearly exclusively in adolescent males. Even less is known about this rare tumor entity, alterations affecting the Wnt-pathway seem to play a pivotal role in tumor biology as activating CTNNB1 mutations have been detected. However, the knowledge of Wnt-pathway changes is still limited. Therefore, we aimed to determine in JAs further insight into Wnt/β-catenin pathway components. In our present study, genetic alterations of the Wnt-pathway members CTNNB1, APC, GSK3β, and Axin2 detected by metaphase comparative genomic hybridization (CGH) were shown to result in elevated transcript levels in the majority of JA samples compared to nasal mucosa stroma (p < 0.001, p = 0.001, p = 0.046, and p = 0.006, respectively). Additionally, amplifications of CTNNB1 were validated by fluorescence in situ hybridization (FISH) and genomic qPCR. Moreover, our mutation analysis detected already known mutations as well as, to the best of our knowledge, mutations and an interstitial deletion of CTNNB1 not described in JAs before. Additionally, a so far unknown transcribed Axin2 splice variant was found, but no further Axin2 mutations. Taken together, our current study supports the importance of aberrant Wnt-signaling as a common event in JAs, most likely by the observed genetic alterations driven by mutations, interstitial deletions but also amplifications of CTNNB1 contributing to the stabilization of β-catenin.

Mesenchymal-endothelial transition in juvenile angiofibroma?

CONCLUSION

Mesenchymal-endothelial transition is proposed for juvenile angiofibromas (JAs). Propranolol might be an interesting new medical option in JA treatment, as it reduces mesenchymal cell growth and decreases the number of CD31-positive cells in vitro.

OBJECTIVE

Juvenile angiofibromas (JAs) are rare fibro-vascular tumors affecting almost exclusively adolescent males. Based on morphological aspects of irregularly configured vascular spaces and clinical features, JAs have been proposed to represent a vascular malformation. In general, mesenchymal-endothelial transition has been noted as an important process in tumorigenesis as well as in embryonal development.

METHODS

The study analyzed effects of vascular endothelial growth factor (VEGF)/basic fibroblast growth factor (bFGF) and propranolol on endothelial differentiation (CD31+) of cultured JA cells and their expression of angiogenic growth factors using aortic ring assay and enzyme-linked immunosorbent assay.

RESULTS

Following VEGF/bFGF supplement to cultured mesenchymal cells, an average of 4.47% (± 2.35%) CD31-positive cells were found (p < 0.001). Propranolol addition reduced the number of CD31-positive cells and inhibited mesenchymal cell growth. The aortic ring assay and ELISA investigation indicated no increased angiogenic growth factor secretion from cultured JA mesenchymal cells.

The presence of tumor-infiltrating IL-17-producing cells in juvenile nasopharyngeal angiofibroma tumor microenvironment is a poor prognostic factor

BACKGROUND

Although juvenile nasopharyngeal angiofibroma (JNA) is a benign tumor histologically, it demonstrates aggressive propensity of locally destructive growth causing bone erosion. The patients with JNA remain high recurrence rate after surgical excision. Th17 cells secrete the proinflammatory cytokine interleukin-17 (IL-17), and play an important role in carcinogenesis and tumor progression. So far, no studies have focused on the significance of IL-17-producing cells in the JNA tumor microenvironment. The current study was designed to investigate the localization and level of tumor-infiltrating IL-17-producing cells in JNA microenvironment. The presence and number of IL-17-producing cells were further analyzed for a possible association with clinicopathological features and disease outcome.

MATERIALS AND METHODS

Immunohistochemistry was used to analyze the expression of IL-17 in a tissue microarray from 70 patients with JNA and 10 control subjects. Correlations between the levels of IL-17 expression and clinicopathologic variables, as well as tumor recurrence, were assessed.

RESULTS

In vessels, the IL-17-producing cells were identified in pericytes and irregular smooth muscle cells, but the matured vascular endothelial cells showed no IL-17 reactivity. The expression of IL-17 in stromal cells was concentrated in the less differentiated and plump cells that contained a central hypochromatic nucleus and single small nucleolus. Chi-square test showed that tumor stage (p=0.09), operation history (p=0.828), operation approach (p=0.159), and volume of intraoperative hemorrhage (p=0.352) were not associated with the expression of IL-17 in JNA patients. However, intratumoral IL-17-producing cells were negatively associated with patient's age (p=0.004). Furthermore, we found that patients with extensive infiltration of IL-17-producing cells had significantly higher recurrence rates than those with less infiltration of IL-17-producing cells (p=0.028). Log rank analysis showed that JNA patients with high levels of IL-17 had significantly shorter disease free survival (DFS) than those with low levels of IL-17 (p=0.004). Univariate Cox regression analysis suggested that IL-17 and patient's age were significantly associated with DFS. Multivariate analysis indicated that high infiltration with IL-17-producing cells was associated with poor DFS. Of all clinicopathological features, IL-17 level was an independent factor predicting the patient's prognosis.

CONCLUSION

In JNA patients, a high level of IL-17-producing cells was negatively associated with patient's age. Patients with extensive infiltration of IL-17-producing cells had significantly higher tumor recurrence rates. High infiltration of IL-17-producing cells in JNA microenvironment is an independent poor prognostic factor for shorter disease-free survival. Future studies further focusing on the role of IL-17 may provide more promising therapeutic methods for extensive JNA tumors.

Anti-proliferative effect of glucocorticoids on mesenchymal cells in juvenile angiofibromas

BACKGROUND

Glucocorticoids (GCs) not only regulate metabolic and inflammatory mechanisms, but also are known to suppress tumor growth. Despite previous detection of glucocorticoid receptors (GRs) in juvenile angiofibromas, their distribution and function have not further been studied.

METHODS

Juvenile angiofibroma tissue (n = 30), nasal mucosa specimens (n = 10), subepithelial stroma of nasal mucosa (n = 20), and primary fibroblasts from juvenile angiofibroma (n = 6) and nasal mucosa samples (n = 6) were analyzed by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence staining. The antiproliferative effect of GCs (dexamethasone, prednisolone, and hydrocortisone) in vitro was assessed using a bromdeoxyuridine (BrdU) assay.

RESULTS

An upregulation of GR transcripts and protein was shown in juvenile angiofibroma tissue and primary mesenchymal cells compared to nasal mucosa. Application of GCs resulted in a significantly higher antiproliferative effect on juvenile angiofibroma versus nasal mucosa fibroblasts in vitro.

CONCLUSION

Expression of GRs and antiproliferative effects of GCs on juvenile angiofibroma fibroblasts offer novel options for the treatment of this unique fibrovascular tumor.

Biological distinctions between juvenile nasopharyngeal angiofibroma and vascular malformation: an immunohistochemical study

The exact nature of juvenile nasopharyngeal angiofibroma (JNA) is still in dispute. In recent years, the main controversy of its nature has focused on hemangioma and vascular malformation. In this study, the immunolocalization of vascular endothelial growth factor (VEGF), VEGF receptor-1/fms-like tyrosine kinase-1 (VEGFR-1/Flt-1), VEGF receptor-2/fetal liver kinase-1 (VEGFR-2/Flk-1), proliferating cell nuclear antigen (PCNA), and CD34 was investigated in 28 cases of JNA and 20 cases of orbital cavernous hemangiomas (OCH). The immunostaining levels of VEGF, Flt-1, and Flk-1 were higher and more frequent in vascular endothelial cells of JNA than those of OCH (p<0.05). The average microvessel density (MVD) marked by CD34 in JNA was (49.3 ± 9.1)/HPF (high power field), which was higher than OCH (29.1 ± 6.7)/HPF (p<0.05). Immunoreactivity of PCNA was localized in both endothelial and stromal cell components of JNA, but was predominantly seen in the stromal cells. However, no PCNA immunoreactivity was identified in any of the stromal and endothelial cells in cases of OCH. The immunostaining levels of CD34, VEGF, Flt-1, Flk-1, and PCNA in JNA were higher than those in OCH. These data support the view that JNA has biological characteristics of an angiogenic histogenetic tumor. In the future, anti-angiogenic therapy may represent a novel treatment strategy for JNA.

Metalloproteinases in juvenile angiofibroma--a collagen rich tumor

Matrix metalloproteinases (MMPs) act in diverse physiological and pathological conditions such as tumor growth and angiogenesis by cleaving extracellular matrix and nonmatrix substrates. MMPs with gelatinase/collagenase activity have not yet been studied in juvenile angiofibroma, a unique fibrovascular tumor with prominent collagen expression. Quantitative real-time polymerase chain reaction studies, Western blot analysis, immunofluorescence studies, gel zymography, and in situ zymography were used to analyze MMP-1, MMP-2, MMP-9, MMP-13, MMP-14, TIMP-1, and TIMP-2 in 9 juvenile angiofibromas and 2 inferior nasal turbinate specimens. Quantitative real-time polymerase chain reaction found significantly elevated expression of MMP-2, MMP-9, and MMP-14 (P < .05) in tumor tissue compared with the inferior nasal turbinate specimens. Western blot analysis detected more prominent MMP-1, MMP-2, and MMP-9 protein levels in juvenile angiofibromas compared with inferior nasal turbinates, but not MMP-13, MMP-14, TIMP-1, and TIMP-2. Immunofluorescent staining proved a mainly stromal localization of the analyzed MMPs. Only MMP-9 and MMP-14 were also detected in vessel walls. MMP-1, MMP-2, and MMP-13 also stained mast cells. Gel zymography indicated increased MMP-2 and MMP-9 gelatinase activity in juvenile angiofibromas compared with inferior nasal turbinates. Finally, in situ zymography detected very high stromal gelatinase/collagenase activity. This study indicates significant expression of MMPs with gelatinase/collagenase activity in juvenile angiofibromas with evidence of a disturbed balance of MMPs to TIMPs toward enhanced MMP activity. These MMPs are assumed to be involved in tumor pathology with an influence on tumor growth and angiogenesis.