We consecutively enrolled stage IV, EGFR-mutant-, and EGFR-TKI-treated patients with SCC....Among the patients with EGFR mutations, shorter progression-free survival (PFS) was observed in SCC compared to adenocarcinoma (4.6 vs. 11.0 months, P<0.001)…Further exploration of EGFR-mutant SCC revealed...Mutations in GRM8 (P=0.025) were associated with improved PFS.