Keratin-15 high expression links with lymph node metastasis and poor survival prognosis in epithelial ovarian cancer patients

Background Keratin-15 (KRT15) involves in the progression and owns prognostic values in several solid cancers, whose clinical role in epithelial ovarian cancer (EOC) is rarely reported. This study aimed to identify the association of KRT15 expression with tumor features and survival of surgical EOC patients. Methods Formalin-fixed paraffin-embedded tumor tissues of 140 EOC patients who underwent tumor resection were retrieved for KRT15 determination using immunohistochemistry (IHC) assay. Results The median (interquartile range) KRT15 IHC score was 0.0 (0.0-1.0), ranging from 0.0 to 12.0. Among all, 36.4% of patients had positive KRT15 expression (IHC score > 0) and 15.0% of patients had high KRT15 expression (IHC score > 3). KRT15 was positively related to lymph node metastasis incidence (P = 0.027), and showed a tendency to correlate to FIGO stage but without statistical significance (P = 0.052), while it was not correlated with age, other tumor features, and tumor markers. Positive KRT15 expression was linked with poor disease-free survival (DFS) (P = 0.009) and overall survival (OS) (P = 0.032). Notably, high KRT15 expression showed an even stronger relationship with worse DFS (P = 0.001) and OS (P < 0.001). After adjustment of multivariable Cox's regression, high KRT15 expression was independently correlated with unfavorable DFS (hazard ratio (HR): 2.241, P = 0.007). Conclusion Even though KRT15 is insufficiently expressed in EOC tissues generally, its positive expression or high expression can predict the lymph node metastasis and poor survival prognosis in EOC patients who undergo tumor resection.