Oncogenic driver mutations in patients with non-small-cell lung cancer at various clinical stages

Oncogenic driver mutations are responsible for the initiation and maintenance of non-small-cell lung cancer (NSCLC). Elucidation of driver mutation occurrence in NSCLC has important clinical implications.

NSCLC at various clinical stages were studied for their oncogenic mutations and their association with patients' disease-free survival (DFS).

Of 488 patients with NSCLC, 28 had EML4-ALK fusions. Female, young age (<60 years old), and nonsmoker patients had significant greater mutation frequencies than male, old age (≥60 years old), and smoker patients, respectively (P<0.05). Of 392 patients with NSCLC, 13 had PIK3CA mutations and 3 had MEK1 mutations. EML4-ALK, PIK3CA, and MEK1 mutations were mutually exclusive. EML4-ALK fusion was found to be of coexistence with EGFR and KRAS mutations in two cases. In stage IA NSCLC, EML4-ALK-positive patients had longer DFS than EML4-ALK-negative patients (P = 0.04). However, in stage IIIA NSCLC, EML4-ALK-positive patients had poorer DFS than EML4-ALK-negative patients (P < 0.01). Moreover, multivariate analysis indicated that in stage IIIA NSCLC EML4-ALK fusion was the only significant indicator for poor DFS (P < 0.001). Furthermore, tumors with EML4-ALK fusions had significantly higher levels of ERCC1, a molecule with a key role in platinum drug efficacy, than tumors without EML4-ALK fusions.

EML4-ALK, PIK3CA, and MEK1 mutations occurred in NSCLC with various distinct clinicopathological characteristics. EML4-ALK fusions could serve as a significant prognostic indicator for locally advanced NSCLC.