Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous disease 
characterized by a tumor microenvironment (TME) that overexpresses vascular 
endothelial growth factor receptor (VEGFR) and fibroblast growth factor receptor 
(FGFR), which can lead to neovascularization, tumor growth and metastasis. 
Therapeutic strategies inhibiting these signaling pathways might lead to 
innovative HNSCC treatments. Five HNSCC cell lines were characterized based on 
VEGFR1-3 and FGFR1-4 expression by sqRT-PCR and treated with three different 
tyrosine kinase inhibitors (TKIs) (nintedanib, dovitinib and pazopanib), all of 
which are effective against VEGFR and FGFR family members. Crystal violet assays 
were performed to analyze the effect of the treatments on cell growth 
(viability). Additionally, VEGFR1-3 and FGFR1-4 expression data were retrieved 
from The Cancer Genome Atlas (TCGA), and statistical analyses were performed to 
investigate the receptor expression level in the different cell lines and the 
efficacy of the single-agent treatments. A correlation analysis was performed to 
quantify the degree of relationship between receptor expression and drug 
efficacy. With the exception of VEGFR2, the targeted receptors were expressed at 
different levels in all of the cell lines. The cell lines exhibited 
concentration-dependent responses with cell line-specific differences toward two 
of the three TKIs (nintedanib and dovitinib). Notably, all of the cell lines 
were resistant to pazopanib. TKIs have potential as therapeutic agents for 
HNSCC. Cell line-specific differences were observed in our in vitro experiments. 
The observed pazopanib resistance could be explained by receptor expression. 
Further investigation is required to determine TKI efficacy in HNSCC.