Increased expression of heat shock protein 27 correlates with peritoneal metastasis in epithelial ovarian cancer

Ovarian cancer is the third most common gynecologic malignancy and the leading cause of death in gynecological cancer. Although the 5-year survival rate is increasing, peritoneal metastasis of ovarian cancer is still a problem because of no potential predictor. Heat shock proteins (HSPs) are a class of functionally related proteins that are highly expressed in many malignant cancers. Previous studies suggest high levels of HSP27 present in the serum of patients with ovarian cancer. In this study, we investigated whether the expression of HSP27 in epithelial ovarian cancer tissue was associated with peritoneal metastasis and whether HSP27 could be used as a potential predictor of peritoneal metastasis in epithelial ovarian cancer. Tissues from epithelial ovarian cancer with or without peritoneal metastasis were collected and the levels of HSP27 messenger RNA and protein determined by real-time polymerase chain reaction and Western blotting. Immunohistochemistry was used to determine the subcellular localization of HSP27. Immunohistochemistry images showed that HSP27 was highly expressed in the cytoplasm of epithelial cancer cells with peritoneal metastasis. Messenger RNA and protein levels of HSP27 were significantly increased in epithelial ovarian cancer with peritoneal metastasis compared with epithelial ovarian cancer without peritoneal metastasis. Higher expression of HSP27 correlated with poor clinical outcome. These data suggest that higher level of HSP27 was associated with peritoneal metastasis in epithelial ovarian cancer. Heat shock protein 27 may be a useful prognostic marker of poor survival and may provide a basis for the development of molecular therapeutics modulating this survival pathway.