S.S. Salamatin1, E.S. Gershtein2, A.N. Khakimov3, E.I. Karamysheva4, T.N. Zabotina5, N.E. Kushlinskii6

1,2,4,6 Russian University of Medicine Ministry of Health of the Russian Federation (Moscow, Russia)

2,3,5,6 N.N. Blokhin National Medical Research Center of Oncology

Ministry of Health of the Russian Federation (Moscow, Russia)

1 salamatinsergey26@yandex.ru, 2 esgershtein@gmail.com, 3 salamakbar97@mail.ru, 4 prof.karamysheva@gmail.com, 5 tatzabotina@yandex.ru, 6 kne3108@gmail.com

The aim of this study was to analyze the levels of soluble PD-1 (sPD-1) and PD-L1 (sPD-L1) in blood serum of breast cancer patients and their association with clinical and morphological characteristics of the disease. The study included 84 patients with breast cancer (stages IIa-IIIc, mean age 52 years) and 49 healthy women (control group, mean age 48 years). Serum sPD-1 and sPD-L1 concentrations were determined using an enzyme-linked immunosorbent assay before the start of specific treatment. A statistically significant decrease in sPD-1 levels and an increase in sPD-L1 concentrations were observed in patients with breast cancer compared to the control group (p<0.0001). A positive correlation was found between sPD-1 and sPD-L1 levels in breast cancer patients (R = 0.41; p<0.001) and no correlation in the control group. sPD-1 levels remained relatively stable across all disease stages, while sPD-L1 demonstrated high variability, particularly at stage IIIb (T4N1/2M0) where concentrations ranged from 1.57 to 527 pg/mL. These data confirm the important role of the PD-1/PD-L1 system in the pathogenesis of breast cancer. The results have potential clinical significance for the development of prognostic criteria and a personalized approach to the use of immunotherapy in patients with breast cancer.

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