Sprouty 1 predicts prognosis in human epithelial ovarian cancer

Sprouty proteins are evolutionary-conserved modulators of receptor tyrosine kinase (RTK) signaling. We have previously reported inverse correlation of the Sprouty 1 (Spry1) protein expression with ovarian cancer cell proliferation, migration, invasion and survival. In the present study, the expression status of Spry1 protein and its clinical relevance in patients with epithelial ovarian cancer were explored. Matched tumor and normal tissue samples from 100 patients with epithelial ovarian cancer were immunohistochemically stained for Spry1. Expression of ERK, p-ERK, Ki67, FGF-2, VEGF and IL-6 and their correlation with Spry1 were also evaluated. In addition, correlation between Spry1 and clinicopathological characteristics and predictive significance of Spry1 for overall survival (OS) and disease-free survival (DFS) were analysed. Our data indicated that Spry1 was significantly downregulated in tumor tissues (p=0.004). Spry1 showed significant inverse correlation with p-ERK/ERK (p=0.045), Ki67 (p=0.010), disease stage (p=0.029), tumor grade (p=0.037), recurrence (p=0.001) and lymphovascular invasion (p=0.042). It was revealed that Spry1 low-expressing patients had significantly poorer OS (p=0.010) and DFS (p=0.012) than those with high expression of Spry1. Multivariate analysis showed that high Spry1 (p=0.030), low stage (p=0.048) and no residual tumor (p=0.007) were independent prognostic factors for a better OS, among which high Spry1 (p=0.035) and low stage (p=0.035) remained as independent predictors of DFS, too. We also found that the expression of Spry1 significantly correlates with the expression of Spry2 (p<0.001), but not that of Spry4. In conclusion, we report for the first time to our knowledge that Spry1 protein is downregulated in human epithelial ovarian cancer. Spry1 expression significantly impacts tumor behavior and shows predictive value as an independent prognostic factor for survival and recurrence.