Gene mutations in squamous cell NSCLC: insignificance of EGFR, KRAS and PIK3CA mutations in prediction of EGFR-TKI treatment efficacy.

BACKGROUND: Epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene (KRAS) and phosphatidylinositide-3-kinase catalytic subunit-alpha (PIK3CA) mutations are biomarkers used for the prediction of efficacy of EGFR tyrosine kinase inhibitors (EGFR-TKIs) in advanced non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: In total, 223 patients with advanced-stage squamous cell NSCLC were tested; 179 patients were treated with EGFR-TKIs. Genetic testing was performed using a combination of denaturing capillary electrophoresis and direct Sanger sequencing.
RESULTS: EGFR mutations were detected in 7.2%; KRAS mutations in 7.4% and PIK3CA mutations in 3.8% of patients. No correlation of EGFR or PIK3CA mutation status with progression-free survival (PFS) (p=0.425; p=0.197), nor overall survival (OS) (p=0.673; p=0.687), was observed. KRAS mutations correlated with shorter OS (p=0.039), but not with PFS (p=0.120).
CONCLUSION: We did not observe any role of EGFR, KRAS, PIK3CA mutations in prediction of EGFR-TKIs efficacy in patients with advanced-stage squamous cell NSCLC.