TUMOR STEM CELLS OF OVARIAN CANCER IN MECHANISMS OF RESISTANCE TO CHEMOTHERAPY
Ovarian cancer (OC) remains one of the most common diseases with a high mortality rate. The aim of the study is to identify the role of tumor stem cells (TSC) in the processes of recurrence, aggressive behavior and resistance to platinum-containing chemotherapy regimens (PCT) in ovarian cancer. The review includes original, randomized trials for the period from 2003 to 2019. Today the question of choosing the primary treatment for disseminated OC is still open. In such cases, treatment should begin with surgery and a course of cytostatic therapy. Not always conducted standard therapy in patients with a diagnosis of ovarian cancer and a similar clinical course of the disease gives the same result. Recently, a special group has been singled out among tumor cell subpopulations, which has a number of common properties with conventional stem cells - TSC. The presence of these cells has been proven in primary tumors and metastatic foci of various localization, moreover, it is the TSC that determine the high tumorigenicity and aggressiveness of the neoplasm. During subsequent courses of PCT, TSC acquire chemoresistance and retain increased metastatic activity. In the interval between the initial treatment and the formation of relapse of the tumor, the organizers retain increased likelihood of re-growth of the tumors. Even when the patient is in periodic remission, the number of highly tumorigenic metastasizing ovarian TSC has a tendency to change their properties, which depends on their microenvironment. The review presents the role of TSC in the process of carcinogenesis and metastasis; the analysis of the effectiveness of the proposed molecular genetic markers with the participation of TSC for predicting relapse of diseases and the formation of resistance of the ovarian cancer to ongoing drug cancer therapy.