EGFR-Mutationsanalyse beim nichtkleinzelligen Lungenkarzinom: Erfahrungen aus der Routinediagnostik

Background: Some patients with non-small cell lung cancer (NSCLC) respond well to therapy with tyrosine kinase inhibitors (TKI). Somatic mutation of the epidermal growth factor receptor (EGFR) gene is an important predictive marker for TKI response. Patients and methods: We performed EGFR mutation analysis in 307 NSCLC (exon 18-21). The data were analyzed for associations with clinical-pathological parameters. Results: Relevant EGFR mutations were found in 25/307 NSCLC (8.1%; 178 biopsies and 129 cytologies). Most mutations were found in exon 19 (50%) followed by the L858R point mutation in exon 21 (12.5%). EGFR mutations were significantly more common in women than in men (16.8% vs. 2.7%; p<0.001) and in adenocarcinoma than in other carcinoma subtypes (11.4% vs. 3.8%; p=0.017). EGFR mutation was associated with TTF-1 positivity (p<0.041). Almost all (96%) mutated NSCLC were TTF-1 positive. Conclusion: In Central Europe, the prevalence of relevant EGFR mutations in NSCLC is <10% of patients with NSCLC. EGFR mutations are more common in women and TTF-1 positive adenocarcinomas. Mutation analysis can be performed both from biopsies and cytologies.