Radiotherapy remains the backbone of head and neck cancer therapy but response is sometimes impeded by tumor radioresistance. Identifying predictive biomarkers of radiotherapy response is a crucial step towards personalized therapy. The aim of this study was to explore gene expression data in search of biomarkers predictive of the response to radiotherapy in head and neck squamous cell carcinoma (HNSCC). Microarray analysis was performed on five cell lines with various intrinsic radiosensitivity, selected from a panel of 29 HNSCC cell lines. The bioinformatics approach included Gene Ontology (GO) enrichment profiling and Ingenuity Pathway Analysis (IPA). The GO-analysis detected 16 deregulated categories from which development, receptor activity, and extracellular region represented the largest groups. Fourteen hub genes (CEBPA, CEBPB, CTNNB1, FN1, MYC, MYCN, PLAU, SDC4, SERPINE1, SP1, TAF4B, THBS1, TP53 and VLDLR) were identified from the IPA network analysis. The hub genes in the highest ranked network, (FN1, SERPINE1, THBS1 and VLDLR) were further subjected to qPCR analysis in the complete panel of 29 cell lines. Of these genes, high FN1 expression associated to high intrinsic radiosensitivity (p=0.047). In conclusion, gene ontologies and hub genes of importance for intrinsic radiosensitivity were defined. The overall results suggest that FN1 should be explored as a potential novel biomarker for radioresistance.