Stanniocalcin-2 May Be a Potentially Valuable Prognostic Marker in Endometrial Cancer: a Preliminary Study.

In the current study, we primarily aimed to investigate stanniocalcin-2 (STC2) protein expression pattern in hysterectomy specimens from patients with endometrioid type endometrial cancer (EC) using immunohistochemistry. Secondly, in order to clarify its prognostic impact, we examined relationships of the expression levels of STC2 with clinicopathologic features and outcome of patients. Histopathology slides of 49 patients were stained with the monoclonal mouse antibody targeting STC2 protein. The expression levels of STC2 were classified based on three-tiered semiquantitative scheme: negative expression, expression level of 0; low-expression, expression level of 1+; and high-expression, expression levels of 2+ and 3+. Recurrence-free survival (RFS) was used as the primary prognostic outcome. Immunohistochemical analysis revealed that 73.5% of tissue samples exhibited positive staining with STC2. The intensity of staining with STC2 was weak in 40.8%, moderate in 22.4%, and strong in 10.2%. Thirty-eight percent of samples showed negative expression; 18.4%, low-expression (1+); and 42.8%, high-expression (2 to 3+). High-expression of STC2 was significantly associated with grade 2-3 tumors (p = 0.026) and disease recurrence (p = 0.013). Multivariate analysis revealed that both the tumor grade and STC2 were independent predictors of disease recurrence. Kaplan-Meier analyses confirmed that patients with high-expression of STC2 had a significantly poorer RFS than those with negative or low STC2 expression (p = 0.037); although overall survival did not differ with respect to expression levels of STC2 (p = 0.148). In conclusion, high-expression of STC2 is a negative prognostic factor, associated with increased risk of recurrence in endometrioid EC.