Stomatitis (or oral mucositis), caused by inflammation of the oral tissues, is a common AE with EGFR-targeted treatments.44 Stomatitis occurred in 21% of patients receiving amivantamab monotherapy, 29% receiving amivantamab plus lazertinib, and 25%-32% receiving amivantamab plus chemotherapy.21,28,32,40. This evidence concerns the gene EGFR and stomatitis.