Clinical, morphological, and molecular-genetic features of ovarian serous borderline tumors

Introduction. Ovarianserous borderline tumor is an indolent neoplasm that requires long-term follow-up to determine clinical outcomes. Consequently, predicting the course of the disease is a significant problem. To solve it, the components of the mitogen-activated protein kinase (MAPK) signaling pathway are analyzed and immunohistochemical antibodies to be used in routine pathology practice are being actively studied. The aim of the paper was to determine clinical, morphological, immunophenotypic, and molecular-genetic features of ovarian serous borderline tumors. Materials and methods. We analyzed surgical specimens of 63 patients with ovarian serous borderline tumor using immunohistochemistry and light microscopy to determine the expression levels of sex steroid hormones, proliferative activity, and the presence of eosinophilic cells, which are pathognomonic for a BRAF mutation. Targeted NGS sequencing was used to detect mutations in the MAPK-signaling pathway. Results. We detected mutations of the MAPK-signaling pathway in more than half of serous borderline tumors. Senescent cells with abundant eosinophilic cytoplasm were associated with BRAF-mutated tumors and demonstrated significant sensitivity and specificity for predicting the mutation. Additionally, patients with the BRAF mutation were less likely to have noninvasive implants in the omentum and peritoneum. There were no statistically significant differences in the assessment of disease-free survival depending on the mutation status of the tumor and the level of expression of sex steroid hormone receptors. The probability of recurrence, depending on the index of proliferative activity, was statistically significantly higher at Ki-67≥7%. Conclusion. Eosinophilic cells in ovarian serous borderline tumors can sufficiently reflect the BRAF mutation, which makes it possible to identify groups of patients for genetic testing and therapeutic stratification. The prognostic value of estrogen and progesterone receptors was not revealed in the analysis of disease-free survival. However, the value of Ki-67≥7% was associated with an increased risk of recurrence, which underscores the importance of assessing proliferative activity for predicting disease outcomes. Keywords: serous borderline tumor, eosinophilic cells, oncogene-induced senescence