EGFR TKIs are associated with various adverse events (AEs), such as skin reactions, diarrhea, and stomatitis,29-31 resulting from EGFR blockade, which differ from the AEs associated with traditional chemotherapy (neutropenia, anemia, and thrombocytopenia).28,32 EGFR TKI AEs may also affect patients’ quality of life and may interfere with patients’ ability to remain on treatment. This evidence concerns the gene EGFR and stomatitis.