{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T14:14:08Z","timestamp":1774275248271,"version":"3.50.1"},"reference-count":30,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,3,22]],"date-time":"2026-03-22T00:00:00Z","timestamp":1774137600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medicina"],"abstract":"<jats:p>Background and Objectives: A combination of chemotherapy and immunotherapy may improve cancer treatment outcomes; however, determining which patient groups will benefit from immunotherapy is critical. Triple-negative breast cancer (TNBC) achieves limited benefit from immune checkpoint inhibitors (ICIs) and anti-PD-L1 blockade therapy. Materials and Methods: In this study, PD-L1 expression levels in myeloid-derived cells in the tumor microenvironment were determined in an experimental TNBC model. Results: Compared with tumor cells, granulocytes, monocytes, and macrophages had significantly higher PD-L1 expression. CD206+ tumor-associated macrophages (TAMs) expressed the highest level of PD-L1. PD-L1 positivity in TAMs was also significantly high in the lung, liver, lymph node, and spleen. Despite treatment initiation in late-stage tumorigenesis, the combination of paclitaxel and the anti-PD-L1 monoclonal antibody atezolizumab significantly reduced tumor growth. In addition, lung metastasis burden was reduced with combined treatment compared with chemotherapy or anti-PD-L1 monotherapy alone. Conclusions: As a result, alterations in PD-L1+ myeloid cells and immune infiltration can be associated with atezolizumab and paclitaxel therapy success in triple-negative breast cancer.<\/jats:p>","DOI":"10.3390\/medicina62030600","type":"journal-article","created":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T13:07:06Z","timestamp":1774271226000},"page":"600","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Alterations in PD-L1+ Myeloid Cells and Immune Infiltration Are Associated with Atezolizumab and Paclitaxel Therapy Success in a Triple-Negative Breast Cancer Model"],"prefix":"10.3390","volume":"62","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5514-4103","authenticated-orcid":false,"given":"Kerim Bora","family":"Yilmaz","sequence":"first","affiliation":[{"name":"Department of Medical and Surgical Research, Institute of Health Sciences, Hacettepe University, 06800 Ankara, Turkey"},{"name":"Department of General Surgery, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3344-468X","authenticated-orcid":false,"given":"Ece","family":"Tavukcuoglu","sequence":"additional","affiliation":[{"name":"Department of Basic Oncology, Cancer Institute, Hacettepe University, 06800 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1066-552X","authenticated-orcid":false,"given":"Hamdullah","family":"Yanik","sequence":"additional","affiliation":[{"name":"Department of Basic Oncology, Cancer Institute, Hacettepe University, 06800 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-5751-7907","authenticated-orcid":false,"given":"Pelin","family":"Se\u00e7ken","sequence":"additional","affiliation":[{"name":"Department of Pathology, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9982-192X","authenticated-orcid":false,"given":"Ertugrul","family":"Celik","sequence":"additional","affiliation":[{"name":"Department of Pathology, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5069-1872","authenticated-orcid":false,"given":"Sumeyra","family":"Guler","sequence":"additional","affiliation":[{"name":"Department of Surgical Oncology, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-1137-8803","authenticated-orcid":false,"given":"Mehmet Mert","family":"Hidiroglu","sequence":"additional","affiliation":[{"name":"Department of General Surgery, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9417-3866","authenticated-orcid":false,"given":"Ibrahim Burak","family":"Bahcecioglu","sequence":"additional","affiliation":[{"name":"Department of Surgical Oncology, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ismail","family":"Erturk","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8967-7303","authenticated-orcid":false,"given":"Mehmet Ali","family":"Gulcelik","sequence":"additional","affiliation":[{"name":"Department of Surgical Oncology, Gulhane Training and Research Hospital, University of Health Sciences, 06010 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Derya","family":"Karakoc","sequence":"additional","affiliation":[{"name":"Department of Medical and Surgical Research, Institute of Health Sciences, Hacettepe University, 06800 Ankara, Turkey"},{"name":"Department of General Surgery, Faculty of Medicine, Hacettepe University, 06800 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gunes","family":"Esendagli","sequence":"additional","affiliation":[{"name":"Department of Medical and Surgical Research, Institute of Health Sciences, Hacettepe University, 06800 Ankara, Turkey"},{"name":"Department of Basic Oncology, Cancer Institute, Hacettepe University, 06800 Ankara, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,22]]},"reference":[{"key":"ref_1","first-page":"265","article-title":"Diagnosis, Prognosis, and Treatment of Triple-Negative Breast Cancer: A Review","volume":"17","author":"Jie","year":"2025","journal-title":"Breast Cancer"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1038\/s41523-022-00468-0","article-title":"Triple negative breast cancer: Pitfalls and progress","volume":"8","author":"Zagami","year":"2022","journal-title":"NPJ Breast Cancer"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Obidiro, O., Battogtokh, G., and Akala, E.O. 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