Overexpression of eIF5A-2 is an adverse prognostic marker of survival in stage I non-small cell lung cancer patients

We have previously isolated an oncogene EIF5A2 (eukaryotic initiation factor 5A2) from a frequently amplified region at 3q of a primary ovarian cancer cell line, and demonstrated its impact on prognosis in human ovarian cancer. Amplification of chromosome 3q has also been detected frequently in non-small cell lung cancer (NSCLC), however, abnormalities of EIF5A2 and its clinicopathologic significance in NSCLC haven't been studied. In our study, the methods of immunohistochemistry and fluorescence in situ hybridization were utilized to examine protein expression and amplification of EIF5A2 in 248 surgically resected NSCLCs (learning cohort) and another validation cohort of 120 stage I NSCLC patients. Overexpression and amplification of EIF5A2 was detected informatively in 48.7% and 13.7% of NSCLCs in learning cohort, 33.3% and 6.0% of NSCLCs in validation cohort. Overexpression of eIF5A-2 was found to correlate with gene amplification, increased cell proliferation and advanced T stage. In learning cohort, eIF5A-2 expression was evaluated as a strong prognostic factor on disease-specific survival, but in subgroup analyses, it only retained its stratified significance in stage I set (Hazards ratio = 2.799, p = 0.001). In validation cohort, the impact of eIF5A-2 expression on survival in stage I NSCLC patients was also observed (Hazard ratio = 2.097, p = 0.014). Our findings suggested that overexpression of eIF5A-2 correlates with local invasion of NSCLC, and might serve as an adverse prognostic marker of survival for stage I NSCLC patients.