Prognostic significance of cytokeratin 19 expression in pancreatic neuroendocrine tumor: A meta-analysis

BACKGROUND: Pancreatic neuroendocrine tumor (PNET) comprises 1–2% of all pancreatic tumors, but its incidence is increasing. Although many studies have investigated the correlation between cytokeratin 19 (CK-19) and PNET, the prognostic significance of CK-19 expression in PNET is inconclusive. METHODS: Eligible studies were retrieved from Pubmed, Elsevier, Embase, Cochrane Library and Web of Science databases. All relevant data were extracted to analyze the relationship between CK-19 and PNET. We utilized a fixed or random effects model to calculate the pooled odds ratio (OR) with 95% confidence intervals (CI). RESULTS: Pooled data indicated CK-19 expression was significantly associated with poor 3- and 5-year overall survival (OS) for PNET, but not for 1-year overall survival. Additionally, positive CK-19 expression was correlated with large tumor size, advanced differentiation grade in World Health Organization-2010 (WHO-2010) and WHO-2004, vascular invasion, lymph node metastasis and liver metastasis. CONCLUSIONS: Positive CK-19 expression can be used as a predictor of poor prognosis of PNET.