CXCR1 and carcinoma: In agreement with our previous studies demonstrating a role for IL-8 signaling in the induction and maintenance of mesenchymal features in carcinoma cells [23, 24], the erlotinib-resistant cell lines generated in this study showed a robust upregulation of the IL-8/IL-8R axis as exhibited by enhanced secretion of IL-8 and enhanced levels of IL-8 receptor alpha (IL-8RA, CXCR1) expression.