HUR MRNA Expression in Ovarian High-grade Serous Carcinoma Effusions is Associated with Poor Survival

The objective of this study was to analyze the expression and clinical role of the RNA-binding molecule HuR in metastatic high-grade ovarian serous carcinoma (HGSC). HUR mRNA expression by reverse-transcription polymerase chain reaction was analyzed in 66 effusions from patients diagnosed with HGSC. Protein expression was analyzed in 262 HGSC effusions using immunohistochemistry. HUR mRNA was detected in all 66 effusions. HUR mRNA levels were unrelated to clinicopathological parameters. However, higher HUR mRNA levels were significantly related to poor overall survival in the entire cohort (P=.023), as well as in analysis limited to patients with prechemotherapy primary diagnosis specimens (P=.001) in univariate analysis. Cox multivariate analysis showed an independent prognostic role for HUR mRNA in the entire cohort (P=.033) and in patients with prechemotherapy primary diagnosis specimens (P=.002). HuR protein was detected in the nucleus and cytoplasm of tumor cells in 258 (98%) of 262 and 153 (58%) of 262 effusions, respectively. Higher HuR protein expression was associated with higher serum Cancer Antigen (CA) 125 levels at diagnosis (P=.01), but its presence at both cellular compartments was otherwise unrelated to clinicopathological parameters or survival. In conclusion, HuR is widely expressed in metastatic HGSC at both the mRNA and protein level. Higher HUR mRNA levels are associated with poor survival in metastatic HGSC, whereas protein expression has no prognostic value.