Prognostic impact of interleukin-6 expression in stage I ovarian clear cell carcinoma

Objective. Ovarian clear cell carcinoma (OCCC) frequently presents at an early stage. In stage I OCCC, the prognosis differs according to substage. In particular, predictive biomarkers and new treatment strategies are needed for stage IC2/IC3 disease. We investigated tumor biology and prognostic factors for stage I OCCC from a clinicopathological perspective, including the expression of ARID1A and IL-6, which are considered critical for OCCC carcinogenesis. Methods. A retrospective cohort study of 192 patients with stage I OCCC treated at a single institution was performed. We calculated overall survival (OS) with respect to 12 clinicopathological parameters that included the unique and diverse histological features of OCCC. Results. The estimated 5-year OS rate in patients with all stage I OCCC was 88.9% during a median of 91 months of follow-up. The multivariate analysis indicated that substage classification and IL-6 expression status were associated with poor OS (p = 0.010 and p = 0.027, respectively). Loss of ARID1A expression had no impact on survival; however, it was associated with substage (p = 0.001), capsule rupture status (p = 0.011), and ascites cytology (p = 0.016). No clear association was found between ARID1A and IL-6 expressions. Histological findings, including the presence of endometriosis, adenofibroma, architectural pattern, and tumor cell type, showed no prognostic effects. Conclusions. Both substage classification and IL-6 expression status may be independent prognostic factors in stage I OCCC. Therefore, IL-6 molecular stratification may be crucial in optimizing therapeutic strategies for early stage OCCC to improve survival. (C) 2017 Elsevier Inc. All rights reserved.