Juvenile Nasopharyngeal Angiofibroma

FGFR3 and FGFR4 overexpression in juvenile nasopharyngeal angiofibroma: impact of smoking history and implications for personalized management

Lifestyle factors, including smoking, have been linked to neoplastic diseases, and reports suggest an association between smoking and overexpression of FGFR (fibroblast growth factor receptor) in certain neoplasms. This study aims to assess the expression of FGFR3 and FGFR4 genes in patients with and without a history of smoking.A total of 118 participants were recruited, including 83 Juvenile Nasopharyngeal Angiofibroma (JNA) patients and 35 healthy participants, the JNA patients were further stratified as smokers and nonsmokers. Total RNA was extracted from the blood & saliva sample by using TRIzol reagent, and quantified using a Nanodrop, and then subjected to gene expression analysis of FGFR3/4 using RT-PCR. Immunohistochemistry analysis was employed using fresh biopsies of JNA to validate the findings. All experiments were performed in triplicates and analysed using the Chi-Square test (P < 0.05). Smokers exhibited significantly lower total RNA concentrations across all sample types (P < 0.001). The study revealed significant upregulation of both FGFR3/4 genes in JNA patients (P < 0.05). Moreover, FGFR3 expression was significantly higher among smokers 66% (95% CI: 53-79%) compared to non-smokers 22% (95% CI: 18-26%). Immunohistochemistry analysis demonstrated moderate to strong staining intensity for FGFR3 among smokers. The study highlights the overexpression of FGFR3/4 genes in JNA patients, with a stronger association observed among smokers. Furthermore, medical reports indicated higher rates of recurrence and bleeding intensity among smokers. These findings emphasize the potential role of FGFR3 as a key molecular factor in JNA, particularly in the context of smoking.

Inhibition of fibroblast growth factor receptor with AZD4547 mitigates juvenile nasopharyngeal angiofibroma

BACKGROUND

Juvenile nasopharyngeal angiofibroma (JNA) is a benign tumor that presents in adolescent males. Although surgical excision is the mainstay of treatment, recurrences complicate treatment. There is a need to develop less invasive approaches for management. JNA tumors are composed of fibroblasts and vascular endothelial cells. We identified fibroblast growth factor receptor (FGFR) and vascular endothelial growth factor (VEGF) expression in JNA-derived fibroblasts. FGFR influences fibroblast proliferation and VEGF is necessary for angiogenesis. We hypothesized that targeting FGFR would mitigate JNA fibroblast proliferation, invasion, and migration, and that targeting the VEGF receptor would attenuate endothelial tubule formation.

METHODS

After informed consent, fibroblasts from JNA explants of 3 patients were isolated. Fibroblasts were treated with FGFR inhibitor AZD4547, 0 to 25 μg/mL for 72 hours and proliferation was quantified using CyQuant assay. Migration and invasion of JNA were assessed using 24-hour transwell assays with subsequent fixation and quantification. Mitigation of FGFR and downstream signaling was evaluated by immunoblotting. Tubule formation was assessed in human umbilical vein endothelial cells (HUVECs) treated with vehicle control (dimethylsulfoxide [DMSO]) or semaxanib (SU5416) as well as in serum-free media (SFM) or JNA conditioned media (CM). Tubule length was compared between treatment groups.

RESULTS

Compared to control, AZD4547 inhibited JNA fibroblast proliferation, migration, and invasion through inhibition of FGFR and downstream signaling, specifically phosphorylation of - p44/42 mitogen activated protein kinase (p44/42 MAPK). JNA fibroblast CM significantly increased HUVEC tubule formation (p = 0.0039).

CONCLUSION

AZD4547 effectively mitigates FGFR signaling and decreases JNA fibroblast proliferation, migration, and invasion. SU5416 attenuated JNA fibroblast-induced tubule formation. AZD4547 may have therapeutic potential in the treatment of JNA.

Imaging in the diagnosis of juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma (JNA) is a rare, benign, highly vascular, and locally aggressive tumor that predominantly occurs in adolescent males. Usually, the presenting symptom is a painless nasal obstruction or epistaxis; however, other symptoms may develop depending on the size and extent of the tumor mass. Owing to the vascularity of the tumor, incisional biopsy is not attempted. The diagnosis is dependent on multiplanar imaging modalities like Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Angiography. These imaging modalities help in assessing the tumor mass, pre-operative embolization of the feeder vessel, and treatment planning. Usually, patients with JNA are diagnosed by otorhinolaryngologists, but here, we present a rare case of JNA reporting to the dental hospital due to a tender palatal swelling.