Twenty-six patients were enrolled, all of whom were diagnosed with adenocarcinoma with EGFR mutations (19del: 16, L858R: 10) except one (squamous cell carcinoma with 19del).
Thirty-three of 249 patients with SQC (13.3%) had EGFR mutations, including exon 19 deletion (19 of 33 patients, 58%), L858R point mutation in exon 21 (12 of 33, 36%), and G719S point mutation in exon 18 (2 of 33, 6%).
Some of these EGFR-mutated PDXs do not respond to erlotinib: LU1868 containing L858R/T790M mutations, and LU0858 having L858R mutation as well as c-MET gene amplification, both squamous cell carcinoma (SCC).