Soluble heat-shock protein 27 in blood serum is a non-invasive prognostic biomarker for ovarian cancer

Ovarian cancer (OC) is the leading cause of death in gynecological oncology, primarily caused by limited prognostic and therapeutic options. The heat shock protein 27 (HSP27) is recognized as a prominent factor in OC, playing a pivotal role in cancer progression machinery such as treatment resistance. Thus, HSP27 may represent an appropriate biomarker for OC diagnosis, prognosis, and therapy response. Extracellular HSP27 levels were measured by enzyme-linked immunosorbent assay (ELISA) in serum samples of OC patients (n = 242) and compared to a non-malignant control group without any history of cancer (n = 200). Correlations between serum levels of HSP27 and clinical pathological parameters were analyzed by bivariate analysis. Survival analyses were carried out by Kaplan-Meier test. This study demonstrated that protein levels of HSP27 are comparable in the blood serum of healthy women and OC patients. However, HSP27 levels are significantly correlated with the volume of ascites, residual tumor mass, and age at first diagnosis in OC patients. Notably, elevated levels of HSP27 demonstrate significantly higher overall survival. Taken together, our findings demonstrate that high levels of circulating HSP27 in serum are associated with improved overall survival of OC patients. Even though functionality of secreted HSP27 is still unclear, serum levels of HSP27 represent a putative non-invasive prognostic biomarker candidate for OC progression.