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Objective: NF1 is a tumor suppressor gene that encodes the neurofibromin protein and negatively regulates Ras signaling. This study was aimed to investigate the molecular, clinical characteristics, and prognostic features of NF1 gene in EGFR mutant lung cancer patients. Method: The next‐generation sequencing (NGS) was used to analyze the data from lung cancer patients in the Guangdong Lung Cancer Institute (GLCI) from June 2016 to December 2020. Results: Somatic NF1 mutations were present in 4.2% (135/3220) of Chinese lung cancer patients. NF1 mutations where clearly enriched in older (p < 0.001), male (p < 0.001), and smoking (p < 0.001) patients. Patients with NF1 mutations were more likely to have TP53 (p = 0.003), BRAF (p = 0.001) and RASA1 (p = 0.026) mutations and mutually exclusive with EGFR mutations (p = 0.006). TP53 mutation had worsen prognosis in cases of NF1 mutant (p = 0.026) or EGFR/NF1 co‐mutant (p = 0.031) lung adenocarcinomas (LUAD) patients. There was no effect on overall survival (OS) in LUAD patients with and without NF1 mutations, even in LUAD driver‐gene negative patients. NF1/EGFR co‐mutation patients had a longer OS than a single mutation of either the EGFR gene (median OS: 47.7 m vs. 30.2 m, hazard ratio [95% CI], 0.47 [0.30–0.74], p = 0.004) or NF1 gene (47.7 m vs. 19.0 m, 0.44 [0.27–0.73], p = 0.003). Furthermore, NF1 mutations significantly prolonged OS in EGFR mutant/TP53 wild‐type LUAD patients (106.5 m vs. 25.5 m, 0.28 [0.13–0.59], p = 0.003) but not in patients with EGFR/TP53 co‐mutations (36.8 m vs. 30.2 m, 0.70 [0.39–1.26], p = 0.280). Conclusion: Our results indicated NF1 mutations served as a good prognostic factor in EGFR mutant/TP53 wild‐type lung cancer patients in this single‐center study. TP53 mutation was obviously enriched in NF1 mutant patients and had shorter OS. [ABSTRACT FROM AUTHOR] more...

Introduction Patients with non-small cell lung cancer (NSCLC) harboring uncommon epidermal growth factor receptor ( EGFR ) mutations are a heterogeneous group exhibiting differential responses to EGFR inhibitors. This retrospective study reviews the prevalence of uncommon EGFR mutations in a Chinese NSCLC cohort and the clinical characteristics and efficacy of EGFR tyrosine kinase inhibitors (TKIs) associated with these patients. Materials andMethods A total of 5363 lung cancer patients were screened and underwent EGFR genotyping at the Guangdong Lung Cancer Institute. Of those with uncommon EGFR mutations, the clinical characteristics and responses to EGFR-TKIs were reviewed retrospectively. Results Uncommon EGFR mutations were observed in 218 patients, comprising 11.9% of all patients with documented EGFR mutations. More smokers (30.7% vs. 24.3%, P = 0.039) and males (54.1% vs. 44.4%, P = 0.007) were among the patients with uncommon mutations compared with common mutations. The most frequent uncommon mutations were exon 20 insertions (30.7%, n = 67), followed by G719X mutations (21.1%, n = 46) and compound L858R mutations (17.0%, n = 37). Favorable efficacy was observed in patients harboring compound L858R or G719X mutations, with a median progression-free survival (PFS) of 15.2 (95% CI: 8.7–21.7) or 11.6 (95% CI: 3.6–19.6) months, respectively. The median PFS of those with the T790 M mutation or an exon 20 insertion was 1.0 (95% CI: 0.0–2.2) and 3.0 (95% CI: 1.3–4.7) months, respectively. Conclusion This study reviewed the prevalence of uncommon EGFR mutations and their sensitivity to EGFR-TKIs. Favorable responses were observed in patients with G719X and compound L858R mutations, indicating that they may benefit from EGFR-TKIs as a first-line therapy. [ABSTRACT FROM AUTHOR] more...