Prognostic significance of insulin-like growth factor-II mRNA-binding protein 3 in urological cancers: a systemic review and meta-analysis

Purpose: Insulin-like growth factor II mRNA-binding protein 3 (IMP3) is an oncofetal protein expressed in diverse malignancies. This study aimed to investigate the prognostic value of IMP3 in urological cancers. Methods: Eligible studies were sought in PubMed, Embase, Cochrane Collaboration and Wanfang databases. Pooled hazard ratios (HRs) with their 95% confidence intervals (CIs) were used to assess the prognostic value of IMP3 in patients with urological cancers. Results: Eight studies including 2,219 patients were enrolled in this meta-analysis. The pooled results showed that IMP3 expression was an indicator of poorer prognosis in patients with urological cancers in terms of overall survival (OS) (HR 2.19, 95% CI 1.35-3.55), disease-specific survival (DSS) (HR 2.10, 95% CI 1.53-2.89), disease-free survival (DFS) (HR 1.49, 95% CI 1.18-1.87) and metastasis-free survival (MFS) (HR 3.80, 95% CI 2.27-6.34). Subgroup analyses revealed that IMP3 was significantly correlated with poorer prognosis in patients with kidney cancer or urothelial cancer in terms of OS (HR 2.52; 95% CI 1.55-4.10), DSS (HR 2.11; 95% CI 1.51-2.95), DFS (HR 2.01; 95% CI 1.40-2.88) and MFS (HR 3.80; 95% CI 2.27-6.34), whereas this association was not found in patients with prostate cancer (OS, HR 1.09, 95% CI 0.45-2.63; DSS, HR 2.06, 95% CI 0.73-5.80; DFS, HR 1.20, 95% CI 0.88-1.62). Conclusions: IMP3 expression might be an indicator of poor prognosis in patients with kidney cancer or urothelial cancer. Further large prospective and well- designed studies utilizing better IMP3 expression assessment processes, are needed to confirm these results especially in patients with prostate cancer.