Prognostic implications of Fibroblast growth factor receptor 1 (FGFR1) gene amplification and protein overexpression in hypopharyngeal and laryngeal squamous cell carcinoma

The gene encoding fibroblast growth factor receptor 1 (FGFR1) is emerging as a therapeutic and prognostic biomarker in various cancer types, including head and neck squamous cell carcinoma (SCC). Here, we investigated the clinicopathologic implication of FGFR1 gene amplification and protein overexpression in hypopharyngeal and laryngeal SCC. Fluorescence in situ hybridization and immunohistochemistry were performed to determine FGFR1 gene amplification and protein overexpression in 209 surgically resected cases. FGFR1 amplification observed in 8 (8/66, 12.1%; 6 hypopharynx and 2 larynx) patients and high FGFR1 expression in 21 (21/199, 10.6%) patients significantly correlated with lymph node metastasis and advanced pathological stages. FGFR1 amplification was also associated with worse disease-free survival in multivariate analysis (hazard ratio = 4.527, P = 0.032). High FGFR1 expression was more frequently observed, consistent with the worsening of the degree of histologic differentiation. FGFR1 amplification may serve as an independent prognostic factor for disease-free survival in hypopharyngeal and laryngeal SCC. Aberrant FGFR signaling caused by FGFR1 gene amplification or protein overexpression may play a crucial role in the malignant evolution and progression of hypopharyngeal and laryngeal SCC, and offer novel therapeutic opportunities in patients with hypopharyngeal and laryngeal SCC that usually lack specific therapeutic targets.