EGFR and cancer: The enrichment analysis result of KEGG pathway show that the target mRNAs of downregulated circRNAs (hsa_circ_0005232, hsa_circ_0000994, hsa_circ_0000690, hsa_circ_0058092, and hsa_circ_0004496) were most significantly enriched in Toll-like receptor signaling pathway, transcriptional misregulation in cancer, Kaposi's sarcoma-associated herpesvirus infection, chemokine signaling pathway, autoimmune thyroid disease, bacterial invasion of epithelial cells, thyroid hormone synthesis, alcoholism, thyroid hormone signaling pathway, and EGFR tyrosine kinase inhibitor resistance (Fig. 6D).