FGF-2 and FGFR-1 might be independent prognostic factors in oral tongue squamous cell carcinoma

Aims Fibroblast growth factor (FGF)-2 and fibroblast growth factor receptor (FGFR)-1 are associated with tumour invasiveness, cell proliferation, angiogenesis, and metastasis. The aims of this study were to investigate FGF-2 expression and FGFR-1 expression in oral epithelial dysplasia (OED) and oral tongue squamous cell carcinoma (OTSCC), and their correlation with OTSCC patients' prognosis. Methods and results One hundred and sixty-seven cases were retrospectively selected, including 85 surgical specimens of patients with OTSCC, 46 incisional biopsies of OTSCC, and 36 incisional biopsies of OED. Tissue sections were subjected to immunohistochemical staining for FGF-2 and FGFR-1, and digitally scored. Elevated scores of FGF-2 and FGFR-1 immunostaining were associated with high-grade OEDs. FGF-2 positivity in the stroma was associated with vascular invasion and a worse prognosis, in both overall survival (OS) and disease-free survival (DFS) analyses, in univariate and multivariate models. FGFR-1 positivity in the stroma was correlated with lymph node metastasis and distant metastasis. FGFR-1 expression in either the malignant cells or the stroma was strongly correlated with shorter OS and DFS. Conclusions Taken together, our findings suggest that increased FGF-2 expression and increased FGFR-1 expression are associated with high-grade OEDs, and are correlated with the presence of metastasis and adverse outcomes in OTSCC patients.