Unique expression of 35 KDa protein in serum and cystic fluid of women with malignant ovarian cysts substantiates its role in disease progression

Objective: The present study was undertaken as a part of a continuing search for proteomic based approaches for the diagnosis of ovarian cancers.Methods: The study comprised four groups of women with: i): malignant ovarian cysts, ii) benign ovarian cysts, iii): breast cancer (positive controls) and, iv) healthy females (negative controls). Serum and cystic fluids were processed for gel electrophoresis (SDS-PAGE). Serum and cystic follicular fluid estradiol and testosterone concentrations were measured by ELISA.Results: Proteomics analysis revealed the presence of a uniquely expressed protein with MW of 35 kDa in the serum and cystic fluid of patients with malignant ovarian cysts. On the other hand a protein of 100 kDa was not expressed in malignant ovarian patients whereas it was differentially expressed in the cystic fluid and serum of other three groups. Although mean values of estradiol levels were discernibly higher in patients with benign ovarian cysts as compared to those with malignant ovarian cysts and of positive and negative controls, difference was not significant. Mean concentrations of estradiol were significantly higher in cystic fluid aspirated from benign cysts as compared to that from malignant cysts.Conclusions: Taken together these data indicate a uniquely expressed protein of 35 kDa in patients with malignant ovarian cysts that may serve as a specific protein biomarker for the differential diagnosis of the ovarian cancer. However, a much larger sample of subjects is required to validate and confirm these findings