Abstract Breast cancer is the most common disease among malignant neoplasms. Some patients develop relapses and metastases even after radical treatment. There are still no accurate methods for determining the risk of such an outcome; recommendations for tactics in this case are based on statistical data on survival in different observation groups. We assumed that the risks of breast cancer progression are closely related to insufficient functioning of the immune system. One of the promising areas in the study of immunodeficiency states is the analysis of TREC and KREC (sections of T- and B-lymphocyte DNA that remain after the maturation of these cells). Objective. The aim of the study was to determine the level of TREC in the blood of patients with and without relapse in the luminal subtype of breast cancer. Materials and methods. The study included 196 patients with luminal Her2-negative subtype with stages I-III. Venous blood of patients was used to assess the level of TREC and KREC. Quantitative analysis of TREC and KREC was performed using the IMMUNO-BIT reagent kit. The analyzer used was: Real-time CFX96 amplifier, Bio-Rad Laboratories, USA. Detecting amplifier DT-96, DNA-Technology, Russia. Statistical analysis was performed using the StatTech v. 4.6.1 program (developer - StatTech LLC, Russia). Results. The median TREC level in the group without relapse was 22.43, in the relapse group - 3.0 copies per 105 cells p 0.001. The results of the study showed a low level of TREC in the blood of patients with disease progression within 1 year, which was regarded as a deficiency of the T-cell link, which plays a major role in controlling tumor growth. Conclusions. The obtained data confirm the opinion that breast cancer is an immune-mediated oncological disease, in which there is a decrease in the activity of the body's immune system. Thus, the assessment of the TREC level against the background of adjuvant therapy may become a new risk factor for relapse in patients with breast cancer. Citation Format: A. Sultanbaev, I. Tuzankina, I. Kolyadina, N. Sultanbaeva, D. Kudlay, S. Musin, K. Menshikov, M. Sultanbaev. Immunological aspects that determine the risk of breast cancer recurrence in patients with early luminal subtype abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS3-10-20.
Султанбаев et al. (Tue,) studied this question.