Glioma Specific Extracellular Missense Mutations in the First Cysteine Rich Region of Epidermal Growth Factor Receptor (EGFR) Initiate Ligand Independent Activation.
Among 134 postoperative recurrence patients with lung adenocarcinoma harboring EGFR-activating mutation (L858R or exon 19 deletion) treated with EGFR-TKIs, we retrospectively analyzed 61 patients treated with EGFR-TKIs as first-line chemotherapy.
In the present study, we report cases of two synchronous lung adenocarcinomas composed of two distinct pathological subtypes with different EGFR gene mutations: a homozygous deletion in exon 19 of the papillary adenocarcinoma subtype and a point mutation of L858R in exon 21 of the tubular adenocarcinoma.
All six L858R-mutant cavitary ADC patients had thick-wall cavity while thick-wall cavity was only identified in one thirds (3/9) of patients with 19DEL.
Thirty-five LADC patients who received epidermal growth factor receptor (EGFR)-TKI therapy, including ten who received tumor rebiopsy after development of resistance, were subjected to picoliter-ddPCR-cfDNA analysis to determine the fraction of cfDNA with TKI-sensitive (L858R and inflame exon 19 deletions) and -resistant (i.e., T790M) mutations, as well as their concordance with mutation status in rebiopsied tumor tissues.
Our patient supports the proposition that somatic mutation L858R in exon 21 of the EGFR gene accounts for complete responsiveness to gefitinib in a Taiwanese female patient with metastatic adenocarcinoma of lung.
The aim of this study was to compare the efficacy and toxicity of gefitinib as first-line therapy and second-line therapy for advanced lung adenocarcinoma patients with positive exon 21 (L858R) or exon 19 deletion of <i>EGFR</i> mutation.
A previously unreported mutation in exon 21 of EGFR, which leads to substitution of alanine for threonine at position 854 (T854A), was identified in one patient with a drug-sensitive EGFR L858R-mutant lung adenocarcinoma after long-term treatment with tyrosine kinase inhibitors.
Compared to those with classic activating EGFR mutations, lung adenocarcinomas with exon 20 insertion mutations were characterized by significantly younger age at diagnosis (P = 0.032 for exon 20 insertions vs. L858R) and shorter relapse-free survival [P = 0.045 for exon 20 insertions versus (vs) exon 19 deletions].
Among the mutations of epidermal growth factor receptor (EGFR), deletions in exon 19 (DEL), and point mutations in exon 21 (L858R) predict the response to EGFR-tyrosine kinase inhibitors (TKIs) in primary lung adenocarcinoma.