Positive expression of Y-box binding protein 1 and prognosis in non-small cell lung cancer: a meta-analysis

BACKGROUND Y-box binding protein 1 (YB-1) belongs to the cold shock domain protein family involved in transcription and translation. We conducted a meta-analysis of the association between YB-1 expression and the survival and clinicopathological features in NSCLC. METHODS PubMed and Embase were searched to identify studies that evaluated the YB-1 expression (by immunohistochemistry) and overall survival (OS) in NSCLC. Hazard ratios (HRs) and 95% confidence intervals (CI) of OS were pooled. Odds ratios (ORs) of clinicopathological features were computed. Meta-analysis was performed using STATA 12.0 software. RESULTS Data on 692 NSCLC patients were collected from six eligible studies. Meta-analysis revealed that YB-1 was associated with worse OS (HR = 1.59, 95% CI [1.27, 2.00], P < 0.001, fixed effect), tumor stage (OR = 0.43, 95% CI [0.22-0.82], P = 0.01, random effect), and depth of invasion (OR = 0.37, 95%CI [0.22-0.63], P < 0.001, fixed effect). A subgroup was analyzed by IHC staining to determine the location of YB-1 positive expression. Poor OS was observed in nucleus staining (pooled HR = 1.86, 95% CI [1.41, 2.45], P < 0.001). However, no statistical significance was observed in combined cytoplasmic and nuclear staining (pooled HR = 1.14, 95% CI [0.76, 1.72], P = 0.536). CONCLUSIONS Meta-analysis indicated that YB-1 overexpression is correlated with worse OS and clinicopathological features in NSCLC. Subgroup analysis revealed that the nucleus expression of YB-1 may be more closely associated with NSCLC prognosis than cytoplasmic expression.