Frequency of EGFR mutations in peruvian patients with non-small cell lung cancer.

e22063 Background: Determination of mutational status of the EGFR gene is important for the adequate choice of targeted therapy with EGFR tyrosine kinase inhibitors (TKI´s) in NSCLC patients. In this study we describe the frequency of EGFR mutations in a large cohort of Peruvian patients. Methods: We evaluated tumor samples from 398 metastatic NSCLC patients tested for known EGFR mutations in exon 18 (G719X), exon 19 (deletions), exon 20 (T790M, S768I and insertions) and exon 21 (L858R). Samples were from a mutational testing program sponsored by a pharmaceutical company. All samples were processed at a central reference laboratory. Results: Fifty five percent of patients were male. Frequency of EGFR mutation was 36.7% (n = 146). Mutation G719X (exon 18) was present in 1% (n = 4) of cases; deletions in exon 19 were present in 19.6% (n = 78) of cases. Mutations in exon 20 had a frequency of 3.5% (n = 14), from which, 8 cases had insertions, 5 cases had the mutation T790M and 1 case had the mutation S768I. ...