ИСТИНА

Although malignant bone tumors in children are rare, they represent an important problem in pediatric oncology: they are characterized by an extremely aggressive clinical course, early metastasis, low sensitivity to chemotherapy and high mortality rates. The aggressive nature of these diseases urgently requires expanded research into their pathogenesis, identification of new targets for drug therapy and modern methods for assessing prognosis. It is known that oxidized derivatives of polyunsaturated fatty acids (PUFA) oxylipins play an important role in the development, invasion, metastasis and immune response of malignant tumors, however, their changes in bone sarcomas have not been previously studied. The aim of this study is to study the oxylipin profile using UPLC-MS/MS in the blood plasma of children with osteosarcoma and Ewing’s tumor. Plasma samples from 20 healthy children in the control group, 29 patients with osteosarcoma, and 23 patients with Ewing tumor (average age of study participants ~12 years) were studied. Analysis of blood plasma samples revealed 32 lipid compounds. The greatest differences with the control group were found in children with Ewing tumors. Concentrations of 4 compounds, oxylipins (lipoxygenase pathway): 9-HODE, 9-HpODE, 13- KODE (derivatives of linoleic acid) and 15-HETE (metabolite of arachidonic acid) were increased in patients with Ewing tumors. Thus, only in Ewing’s tumor was a significant increase in the synthesis of lipoxygenase metabolites observed. In contrast to other types of malignant tumors that we have previously studied, where we observed pronounced changes in various proinflammatory oxylipins, the data obtained in bone sarcomas in children may indicate a weakly expressed inflammatory response to the tumor and, probably, a less active activation of the body’s defense mechanisms. The work was supported by the System of Grants for Scientific Projects of the Peoples’ Friendship University of Russia No. 214853-2-000.