It is very important to find new diagnostic and prognostic biomarkers. A total of 79 patients were enrolled in the study. The study group consisted of 37 patients with epithelial ovarian cancer, and the control group consisted of 42 patients with benign ovarian lesions. Five proteins involved in the immune response were studied: BTLA, CD27, CD70, CD28, CD80. The study material was serum and peritoneal fluid. The ROC curve was plotted, and the area under the curve was calculated to characterize the sensitivity and specificity of the studied parameters. Univariate and multivariate analyses were performed simultaneously using the Cox regression model. The cut-off level of CD27 was 120.6 pg/mL, with the sensitivity and specificity of 66 and 84% (p = 0.014). Unfavorable prognostic factors determined in serum were: CD27 (for PFS: HR 1.26, 95% CI 1.21–1.29, p = 0.047; for OS: HR 1.20, 95% CI 1.15–1.22, p = 0.014). Unfavorable prognostic factors determined in peritoneal fluid were: BTLA (for OS: HR 1.26, 95% CI 1.25–1.31, p = 0.033). We conclude that CD27 should be considered as a potential biomarker in the diagnosis of ovarian cancer. BTLA and CD27 are unfavorable prognostic factors for ovarian cancer.

The aim of this study was to evaluate the influence of β-endorphins and serotonin on the course of treatment, disease-free time, and overall survival of patients with ovarian cancer. This study may contribute to the identification of modifiable factors that may influence the treatment of ovarian cancer. The research was carried out in a group of 162 patients of which 139 respondents were included in the research; ovarian cancer was diagnosed in 78 of these patients. The study consisted of three stages. In the first stage of diagnostics, a survey among the patients was carried out. In the second stage—5 mL of blood was collected from each patient (n = 139) in the preoperative period to determine the concentration of β-endorphin and serotonin. In the third stage—blood samples were collected from those patients who had completed chemotherapy treatment or had surgery. Concentrations of β-endorphin and serotonin were measured by the Luminex method, using the commercial Luminex Human Discovery Assay kit. The average age of the patients was 62.99 years. The level of β-endorphin significantly differs among patients diagnosed with ovarian cancer and among patients in the control group (202.86; SD—15.78 vs. 302.00; SD—24.49). A lower level of β-endorphins was found in the patients with a recurrence of the neoplastic process compared to those without recurrence (178.84; SD—12.98 vs. 205.66; SD—13.37). On the other hand, the level of serotonin before chemotherapy was higher in the group of people with disease recurrence compared to those without recurrence (141.53; SD—15.33 vs. 134.99; SD—10.08). Statistically significantly positive correlations were found between the level of β-endorphin and both disease-free time (β-endorphin levels before chemotherapy: rho Spearman 0.379, p < 0.027; β-endorphin levels after chemotherapy: rho Spearman 0.734 p < 0.001) and survival time (β-endorphin levels before chemotherapy: rho Spearman 0.267, p < 0.018; β-endorphin levels after chemotherapy: rho Spearman 0.654 p < 0.001). 1. The levels of serotonin and β-endorphin levels are significantly related to ovarian cancer and change during treatment. 2. High mean preoperative concentrations of β-endorphins were significantly related to overall survival and disease-free time.