Spectrum of <i>EGFR</i> Gene Copy Number Changes and <i>KRAS</i> Gene Mutation Status in Korean Triple Negative Breast Cancer Patients

<div><p>Anti-epidermal growth factor receptor (EGFR) therapy has been tried in triple negative breast cancer (TNBC) patients without evaluation of molecular and clinical predictors in several randomized clinical studies. Only fewer than 20% of metastatic TNBCs showed response to anti-EGFR therapy. In order to increase the overall response rate, first step would be to classify TNBC into good or poor responders according to oncogenic mutation profiles. This study provides the molecular characteristics of TNBCs including <i>EGFR</i> gene copy number changes and mutation status of <i>EGFR</i> and <i>KRAS</i> gene in Korean TNBC patients. Mutation analysis for <i>EGFR, KRAS, BRAF</i> and <i>TP53</i> from a total of 105 TNBC tissue samples was performed by direct sequencing, peptide nucleic acid-mediated PCR clamping method and real-time PCR. Copy number changes of <i>EGFR</i> gene were evaluated using multiplex ligation-dependent probe amplification. Out of all 105 TNBCs, 15.2% (16/105) showed <i>EGFR</i> copy number changes. Among them, increased or decreased EGFR copy number was detected in 13 (5 single copy gain, 2 amplification and 4 high-copy number amplification) and 3 cases (3 hemizygous deletion), respectively. The mutation frequencies of <i>KRAS</i>, <i>EGFR</i> and <i>TP53</i> gene were 1.9% (G12V and G12D), 1.0% (exon 19 del) and 31.4%, respectively. There was no <i>BRAF</i> V600E mutation found. Future studies are needed to evaluate the clinical outcomes of TNBC patients who undergo anti-EGFR therapy according to the genetic status of <i>EGFR</i>.</p>