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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="research-article" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Advances in Molecular Oncology</journal-id><journal-title-group><journal-title xml:lang="en">Advances in Molecular Oncology</journal-title><trans-title-group xml:lang="ru"><trans-title>Успехи молекулярной онкологии</trans-title></trans-title-group></journal-title-group><issn publication-format="print">2313-805X</issn><issn publication-format="electronic">2413-3787</issn><publisher><publisher-name xml:lang="en">Publishing House ABV Press</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">792</article-id><article-id pub-id-type="doi">10.17650/2313-805X-2025-12-4-100-108</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>RESEARCH ARTICLES</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>ЭКСПЕРИМЕНТАЛЬНЫЕ СТАТЬИ</subject></subj-group><subj-group subj-group-type="article-type"><subject>Research Article</subject></subj-group></article-categories><title-group><article-title xml:lang="en">Regulatory T cells in the primary tumor growth lesion in colorectal cancer</article-title><trans-title-group xml:lang="ru"><trans-title>Регуляторные Т-клетки в первичном очаге опухолевого роста при колоректальном раке</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0009-0008-2228-3351</contrib-id><contrib-id contrib-id-type="spin">7136-0110</contrib-id><name-alternatives><name xml:lang="en"><surname>Kryukova</surname><given-names>V. V.</given-names></name><name xml:lang="ru"><surname>Крюкова</surname><given-names>В. В.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><email>viktorcepelev@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-2166-5154</contrib-id><contrib-id contrib-id-type="spin">4624-4537</contrib-id><name-alternatives><name xml:lang="en"><surname>Tsepelev</surname><given-names>V. L.</given-names></name><name xml:lang="ru"><surname>Цепелев</surname><given-names>В. Л.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><email>viktorcepelev@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-8601-3499</contrib-id><contrib-id contrib-id-type="spin">5228-8808</contrib-id><name-alternatives><name xml:lang="en"><surname>Tereshkov</surname><given-names>P. P.</given-names></name><name xml:lang="ru"><surname>Терешков</surname><given-names>П. П.</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><email>viktorcepelev@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Chita State Medical Academy, Ministry of Health of Russia</institution></aff><aff><institution xml:lang="ru">ФГБОУ ВО «Читинская государственная медицинская академия» Минздрава России</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2025-12-14" publication-format="electronic"><day>14</day><month>12</month><year>2025</year></pub-date><volume>12</volume><issue>4</issue><issue-title xml:lang="en"/><issue-title xml:lang="ru"/><fpage>100</fpage><lpage>108</lpage><history><date date-type="received" iso-8601-date="2025-07-04"><day>04</day><month>07</month><year>2025</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2025, Kryukova V.V., Tsepelev V.L., Tereshkov P.P.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2025, Крюкова В.В., Цепелев В.Л., Терешков П.П.</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="en">Kryukova V.V., Tsepelev V.L., Tereshkov P.P.</copyright-holder><copyright-holder xml:lang="ru">Крюкова В.В., Цепелев В.Л., Терешков П.П.</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/><license><ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://creativecommons.org/licenses/by/4.0</ali:license_ref></license></permissions><self-uri xlink:href="https://umo.abvpress.ru/jour/article/view/792">https://umo.abvpress.ru/jour/article/view/792</self-uri><abstract xml:lang="en"><p><bold>Introduction</bold>. Regulatory T cells (Treg) have pro-oncogenic activity, inhibit the immune response and therefore can be a significant target for immunotherapeutic methods of treating colorectal cancer (CRC). Currently, the role of regulatory T cells in the mechanisms of carcinogenesis, as well as the participation of co-inhibitory and co-stimulating proteins of the immune system in the formation of tumor immunosuppression in CRC, is insufficiently studied.</p> <p><bold>Aim</bold>.<bold> </bold>To determine the content of Treg subtypes in the primary tumor focus in patients with CRC and to evaluate the expression level of co-stimulating and co-inhibitory proteins on their membrane.</p> <p><bold>Materials and methods</bold>. The main group consisted of 105 patients with stage III colon adenocarcinoma; the control group – 75 patients with non-neoplastic diseases of the colon. The object of the study was tumor-infiltrating T lymphocytes, which were isolated by an enzymatic method. Determination of Treg subtypes, as well as expression of programmed cell death 1 (PD-1) and inducible T-cell costimulator (ICOS) proteins, was performed by flow cytometry. Treg was identified as CD19<sup>−</sup>CD3<sup>+</sup>CD4<sup>+</sup>CD25<sup>high</sup>CD127<sup>−</sup>. Based on the expression of CD45RA and CD197, Treg subtypes were determined as naive (CD45RA<sup>+</sup>CD197<sup>+</sup>), central memory (CD45RA<sup>–</sup>CD197<sup>+</sup>), effector memory (CD45RA<sup>–</sup>CD197<sup>–</sup>), and terminally differentiated (CD45RA<sup>+</sup>CD197<sup>–</sup>). The significance of differences in the parameters of the main and control groups was assessed using the nonparametric Mann–Whitney U test.</p> <p><bold>Results</bold>. In the primary focus of tumor growth in CRC, the content of Treg increases by 4.4 times. At the same time, the ratio of Treg subtypes in the tumor microenvironment changes, which is expressed in a 1.4-fold decrease in the number of naive cells, as well as a 2.8-fold increase in the number of effector memory Treg and a 3.1-fold increase in terminally differentiated lymphocytes. Tumor-infiltrating Treg expressed the ICOS 2 times more strongly compared to the control. A 20 % increase in the number of Treg PD-1<sup>+</sup>ICOS<sup>+</sup> was established. The number of Treg PD-1<sup>−</sup>ICOS<sup>−</sup> cells in the primary tumor focus decreased by 1.4 times compared to the control group.</p> <p><bold>Conclusion</bold>. In patients with CRC, the number of naive Treg decreases in the primary tumor focus and the relative content of differentiated effector cells increases. In the tumor microenvironment in CRC, the number of Tregs increases, expressing on their surface both the costimulating molecule ICOS and the co-inhibitory receptor PD-1.</p></abstract><trans-abstract xml:lang="ru"><p><bold>Введение</bold>. Регуляторные Т-клетки (T-рег) обладают проонкогенной активностью, ингибируют иммунный ответ и поэтому могут быть значимой мишенью для иммунотерапевтических методов лечения колоректального рака (КРР). В настоящее время недостаточно изучена роль регуляторных T-клеток в механизмах канцерогенеза, а также участие коингибирующих и костимулирующих белков иммунной системы в формировании опухолевой иммуносупрессии при данной патологии.</p> <p><bold>Цель исследования</bold> – определить содержание подтипов T-рег в первичном очаге опухолевого роста у больных КРР и оценить уровни экспрессии костимулирующих и коингибирующих белков на их мембране.</p> <p><bold>Материалы и методы</bold>.<bold> </bold>В<bold> </bold>основную группу вошли 105 больных с аденокарциномой толстой кишки III стадии, в контрольную – 75 пациентов с неопухолевыми заболеваниями ободочной кишки. Объектом исследования явились инфильтрирующие опухоль Т-лимфоциты, которые выделяли ферментативным методом. Определение подтипов<bold> </bold>Т-рег, а также экспрессии рецептора программируемой клеточной гибели (PD-1) и индуцируемого костимулятора T-лимфоцитов (ICOS) проводили с помощью проточной цитометрии. Т-рег идентифицировали как CD19<sup>–−</sup>CD3<sup>+</sup>CD4<sup>+</sup>CD25<sup>high</sup>CD127<sup>−</sup>. На основе экспрессии CD45RA и CD197 выявлены подтипы Т-рег: наивные (CD45RА<sup>+</sup>CD197<sup>+</sup>), центральной памяти (CD45RА<sup>–</sup>CD197<sup>+</sup>), эффекторной памяти (CD45RА<sup>–</sup>CD197<sup>–</sup>) и терминально-дифференцированные (CD45RА<sup>+</sup>CD197<sup>–</sup>). Значимость различий в показателях между основной и контрольной группами оценивали с использованием непараметрического U-критерия Манна–Уитни.</p> <p><bold>Результаты</bold>.<bold> </bold>В первичном очаге опухолевого роста при КРР в 4,4 раза увеличивается содержание Т-рег. Одновременно с этим изменяется соотношение подтипов Т-рег в опухолевом микроокружении, что выражается в уменьшении в 1,4 раза количества наивных клеток, а также увеличении в 2,8 раза количества Т-рег эффекторной памяти и в 3,1 раза – терминально-дифференцированных лимфоцитов. Опухоль-инфильтрирующие Т-рег в 2 раза сильнее экспрессировали ICOS по сравнению с контролем. Установлено увеличение на 20 % количества Т-рег PD-1<sup>+</sup>ICOS<sup>+</sup>. Количество клеток T-рег PD-1<sup>−</sup>ICOS<sup>−</sup> в первичном очаге опухолевого роста в группе аденокарциномы толстой кишки уменьшилось в 1,4 раза по сравнению с контрольной группой.</p> <p><bold>Заключение</bold>.<bold> </bold>У больных КРР в первичном очаге опухолевого роста уменьшается количество наивных Т-рег и увеличивается относительное содержание дифференцированных эффекторных клеток. В опухолевом микроокружении при КРР возрастает количество Т-рег, экспрессирующих на своей поверхности как костимулирующую молекулу ICOS, так и коингибирующий рецептор PD-1.</p></trans-abstract><kwd-group xml:lang="en"><kwd>colorectal cancer</kwd><kwd>regulatory T cell</kwd><kwd>expression</kwd><kwd>programmed cell death protein</kwd><kwd>inducible T-lymphocyte costimulator</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>колоректальный рак</kwd><kwd>регуляторная Т-клетка</kwd><kwd>экспрессия</kwd><kwd>белок программируемой клеточной гибели</kwd><kwd>индуцируемый костимулятор T-лимфоцитов</kwd></kwd-group><funding-group><funding-statement xml:lang="en">Chita State Medical Academy</funding-statement><funding-statement xml:lang="ru">Читинская государственная медицинская академия</funding-statement></funding-group></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Siegel R.L., Wagle N.S., Cercek A. et al. Colorectal cancer statistics. 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