BCL11A overexpression predicts survival and relapse in non-small cell lung cancer and is modulated by microRNA-30a and gene amplification

Background: Aberrant activation of the proto-oncogene B-cell lymphoma/leukemia 11A (BCL11A) has been implicated in the pathogenesis of leukemia and lymphoma. However, the clinical significance of BCL11A in non-small cell lung cancer (NSCLC) remains unknown. Results: We examined BCL11A expression at the protein and mRNA levels in a cohort (n = 114) of NSCLC patients and assessed the relationship between BCL11A expression and clinicopathological parameters. Data from array-based Comparative Genomic Hybridization (aCGH) and microRNA transfection experiments were integrated to explore the potential mechanisms of abnormal BCL11A activation in NSCLC. Compared to adjacent non-cancerous lung tissues, BCL11A expression levels were specifically upregulated in NSCLC tissues at both the mRNA (t = 9.81, P < 0.001) and protein levels. BCL11A protein levels were higher in patients with squamous histology (chi(2) = 15.81, P = 0.001), smokers (chi(2) = 8.92, P = 0.004), patients with no lymph node involvement (chi(2) = 5.14, P = 0.029), and patients with early stage disease (chi(2) = 3.91, P = 0.048). A multivariate analysis demonstrated that in early stage NSCLC (IA-IIB), BCL11A was not only an independent prognostic factor for disease-free survival (hazards ratio [HR] 0.24, 95% confidence interval [CI] 0.12-0.50, P < 0.001), but also for overall survival (HR = 0.23, 95% CI 0.09-0.61, P = 0.003). The average BCL11A expression level was much higher in SCC samples with amplifications than in those without amplifications (t = 3.30, P = 0.023). Assessing functionality via an in vitro luciferase reporter system and western blotting, we found that the BCL11A protein was a target of miR-30a. Conclusions: Our results demonstrated that proto-oncogene BCL11A activation induced by miR-30a and gene amplification may be a potential diagnostic and prognostic biomarker for effective management of this disease.