Upregulated interleukin-6 expression contributes to erlotinib resistance in head and neck squamous cell carcinoma.

Despite the role of epidermal growth factor receptor (EGFR) signaling in head and neck squamous cell carcinoma (HNSCC) development and progression, clinical trials involving EGFR tyrosine kinase inhibitors (TKIs) have yielded poor results in HNSCC patients. Mechanisms of acquired resistance to the EGFR TKI erlotinib was investigated by developing erlotinib-resistant HNSCC cell lines and comparing their gene expression profiles with their parental erlotinib-sensitive HNSCC cell lines using microarray analyses and subsequent pathway and network analyses. Erlotinib-resistant HNSCC cells displayed a significant upregulation in immune response and inflammatory pathways compared to parental cells.