Background: We present a comprehensive analysis of KRAS, PIK3CA, MET, and non-sensitizing EGFR mutations in advanced non-small cell lung cancer (NSCLC) patients treated with tyrosine kinase inhibitors (TKIs), with the aim of clarifying the relative contribution of these molecular alterations to resistance.
Patients and methods: One hundred and sixty-six patients with advanced NSCLC treated with EGFR-TKIs with available archival tissue specimens were included. EGFR (exons 18-21), KRAS (exons 2, 3), PIK3CA (exons 9, 20), and MET (exons 14, 15) mutations were analyzed using PCR-based sequencing. Among all the mutations evaluated, only KRAS, PIK3CA, MET, and non-sensitizing EGFR mutations, defined as "TKI non-sensitizing mutations" were used for response, time to progression (TTP), and overall survival (OS) analysis.
Results: TKI non-sensitizing mutations were associated with disease progression (p = 0.001), shorter TTP (p < 0.0001), and worse OS (p = 0.03). Cox's multivariate analysis including histology and performance status showed that TKI non-sensitizing mutations were independent factors for shorter TTP (p < 0.0001) and worse OS (p = 0.01).
Conclusions: When KRAS, PIK3CA, MET, and non-sensitizing EGFR mutations are concomitant, up to 96.0% of NSCLC patients unlikely to respond to TKIs can be identified, and they represented independent negative prognostic factors. Comprehensive molecular dissection of EGFR signaling pathways should be considered to select advanced NSCLC patients for TKIs therapies.