{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,29]],"date-time":"2026-08-29T12:26:18Z","timestamp":1788006378876,"version":"build-2784847793"},"reference-count":30,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T00:00:00Z","timestamp":1783468800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"MSD, Mexico"},{"id":[{"id":"https:\/\/ror.org\/02h9n8v16","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background: Pembrolizumab-containing regimens have become the standard of care across the spectrum of triple-negative breast cancer (TNBC). While their use in the neoadjuvant setting is independent of biomarker status, their application in metastatic disease remains strictly contingent upon PD-L1 expression. Given that PD-L1 prevalence can vary significantly by ethnicity and geography, the lack of specific data for the Mexican population creates a challenge for optimizing treatment in the metastatic setting. This study sought to characterize PD-L1 positivity rates in a Mexican TNBC cohort to better define the local molecular landscape. Methods: We conducted a retrospective study across two cancer centers in Mexico to assess PD-L1 positivity in a cohort of women with TNBC (stages I\u2013IV) diagnosed between 2006 and 2021. PD-L1 expression was assessed and evaluated centrally using the 22C3 pharmDx assay, with a Combined Positive Score (CPS) of \u22651 considered positive. We explored the association between PD-L1 expression and clinicopathological features. Results: Of the 298 TNBC patients identified, 285 (96%) had sufficient tissue for CPS evaluation and thus were included in the analysis. PD-L1 positivity was observed in 29.1% of the cohort, and 13.3% of patients had a CPS \u2265 10. PD-L1 positivity was associated with higher histological grades (91.3% vs. 78.5%, p = 0.035) and TILs \u2265 30% (22.2% vs. 10.0%, p = 0.007). Additionally, pre-treatment surgical specimens were more frequently PD-L1 positive than tumor biopsies (56.6% vs. 30.7%, p &lt; 0.001). Conclusions: This study characterizes the PD-L1 landscape in Mexican women with TNBC, reporting a 29.1% prevalence of CPS \u2265 1. The strong association between PD-L1 positivity and high TILs\/histological grade highlights the role of the immune microenvironment in these aggressive phenotypes. Given the significant variability observed between specimens (biopsy vs. surgical), clinicians should consider the dynamic nature of PD-L1 expression when choosing treatment strategies.<\/jats:p>","DOI":"10.3390\/cancers18142182","type":"journal-article","created":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T15:40:09Z","timestamp":1783525209000},"page":"2182","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Programmed Death-Ligand 1 Expression in Triple-Negative Breast Cancer: Insights from a Mexican Cohort"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3587-339X","authenticated-orcid":false,"given":"Cynthia","family":"Villarreal-Garza","sequence":"first","affiliation":[{"name":"Oncology Institute and Breast Cancer Center, Hospital Zambrano Hellion TecSalud, Tecnologico de Monterrey, San Pedro Garza Garcia 66260, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-5483-0487","authenticated-orcid":false,"given":"C\u00e9sar Octavio","family":"Lara-Torres","sequence":"additional","affiliation":[{"name":"Subdirecci\u00f3n de Patolog\u00eda, Instituto Nacional de Cancerolog\u00eda, Mexico City 14080, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3247-4051","authenticated-orcid":false,"given":"Jesus Edgardo","family":"Hernandez-Hernandez","sequence":"additional","affiliation":[{"name":"Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey 64710, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniela","family":"V\u00e1zquez Ju\u00e1rez","sequence":"additional","affiliation":[{"name":"Oncology Institute and Breast Cancer Center, Hospital Zambrano Hellion TecSalud, Tecnologico de Monterrey, San Pedro Garza Garcia 66260, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gabriela Sof\u00eda","family":"G\u00f3mez-Mac\u00edas","sequence":"additional","affiliation":[{"name":"Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey 64710, Mexico"},{"name":"Facultad de Medicina del Hospital Universitario, Universidad Aut\u00f3noma de Nuevo Le\u00f3n, Monterrey 64460, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paula","family":"Cabrera-Galeana","sequence":"additional","affiliation":[{"name":"Subdirecci\u00f3n de Oncolog\u00eda y Hematolog\u00eda, Instituto Nacional de Cancerolog\u00eda, Mexico City 14080, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fany Iris","family":"Porras-Reyes","sequence":"additional","affiliation":[{"name":"Subdirecci\u00f3n de Patolog\u00eda, Instituto Nacional de Cancerolog\u00eda, Mexico City 14080, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"V\u00edctor Manuel","family":"P\u00e9rez-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Subdirecci\u00f3n de Patolog\u00eda, Instituto Nacional de Cancerolog\u00eda, Mexico City 14080, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonio","family":"Nateras-P\u00e9rez","sequence":"additional","affiliation":[{"name":"MSD, Mexico City 01090, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-9765-4530","authenticated-orcid":false,"given":"Gabriela","family":"Lugo-Martinez","sequence":"additional","affiliation":[{"name":"MSD, Mexico City 01090, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7325-8569","authenticated-orcid":false,"given":"Alejandro","family":"Aranda-Gutierrez","sequence":"additional","affiliation":[{"name":"Oncology Institute and Breast Cancer Center, Hospital Zambrano Hellion TecSalud, Tecnologico de Monterrey, San Pedro Garza Garcia 66260, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alejandro","family":"Mohar","sequence":"additional","affiliation":[{"name":"Unidad de Investigaci\u00f3n Biom\u00e9dica en C\u00e1ncer, Instituto Nacional de Cancerolog\u00eda-Instituto de Investigaciones Biom\u00e9dicas, Universidad Nacional Aut\u00f3noma de M\u00e9xico (UNAM), Mexico City 14080, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,8]]},"reference":[{"key":"ref_1","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_2","doi-asserted-by":"crossref","first-page":"2147","DOI":"10.1056\/NEJMoa1612645","article-title":"Adjuvant Capecitabine for Breast Cancer after Preoperative Chemotherapy","volume":"376","author":"Masuda","year":"2017","journal-title":"N. Engl. J. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2394","DOI":"10.1056\/NEJMoa2105215","article-title":"Adjuvant Olaparib for Patients with BRCA1- or BRCA2-Mutated Breast Cancer","volume":"384","author":"Tutt","year":"2021","journal-title":"N. Engl. J. Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"523","DOI":"10.1056\/NEJMoa1706450","article-title":"Olaparib for Metastatic Breast Cancer in Patients with a Germline BRCA Mutation","volume":"377","author":"Robson","year":"2017","journal-title":"N. Engl. J. Med."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"753","DOI":"10.1056\/NEJMoa1802905","article-title":"Talazoparib in Patients with Advanced Breast Cancer and a Germline BRCA Mutation","volume":"379","author":"Litton","year":"2018","journal-title":"N. Engl. J. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"810","DOI":"10.1056\/NEJMoa1910549","article-title":"Pembrolizumab for Early Triple-Negative Breast Cancer","volume":"382","author":"Schmid","year":"2020","journal-title":"N. Engl. J. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1981","DOI":"10.1056\/NEJMoa2409932","article-title":"Overall Survival with Pembrolizumab in Early-Stage Triple-Negative Breast Cancer","volume":"391","author":"Schmid","year":"2024","journal-title":"N. Engl. J. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1056\/NEJMoa2202809","article-title":"Pembrolizumab plus Chemotherapy in Advanced Triple-Negative Breast Cancer","volume":"387","author":"Cortes","year":"2022","journal-title":"N. Engl. J. Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"5628","DOI":"10.1158\/1078-0432.CCR-21-0343","article-title":"Characteristics and Spatially Defined Immune (Micro)Landscapes of Early-Stage PD-L1\u2013Positive Triple-Negative Breast Cancer","volume":"27","author":"Carter","year":"2021","journal-title":"Clin. Cancer Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1186\/s13058-023-01724-2","article-title":"Comparison of SP142 and 22C3 PD-L1 Assays in a Population-Based Cohort of Triple-Negative Breast Cancer Patients in the Context of Their Clinically Established Scoring Algorithms","volume":"25","author":"Sigurjonsdottir","year":"2023","journal-title":"Breast Cancer Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1136\/jcp-2022-208637","article-title":"Comparison of Assessment of Programmed Death-Ligand 1 (PD-L1) Status in Triple-Negative Breast Cancer Biopsies and Surgical Specimens","volume":"77","author":"Noske","year":"2023","journal-title":"J. Clin. Pathol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2108","DOI":"10.1056\/NEJMoa1809615","article-title":"Atezolizumab and Nab-Paclitaxel in Advanced Triple-Negative Breast Cancer","volume":"379","author":"Schmid","year":"2018","journal-title":"N. Engl. J. Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1635","DOI":"10.3332\/ecancer.2023.1635","article-title":"Real-World Data on Triple-Negative Breast Cancer in Latin America and the Caribbean","volume":"17","author":"Tiscoski","year":"2023","journal-title":"Ecancermedicalscience"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"994","DOI":"10.1016\/j.annonc.2021.05.801","article-title":"Primary Results from IMpassion131, a Double-Blind, Placebo-Controlled, Randomised Phase III Trial of First-Line Paclitaxel with or without Atezolizumab for Unresectable Locally Advanced\/Metastatic Triple-Negative Breast Cancer","volume":"32","author":"Miles","year":"2021","journal-title":"Ann. Oncol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1279","DOI":"10.1093\/annonc\/mdz158","article-title":"A Randomised Phase II Study Investigating Durvalumab in Addition to an Anthracycline Taxane-Based Neoadjuvant Therapy in Early Triple-Negative Breast Cancer: Clinical Results and Biomarker Analysis of GeparNuevo Study","volume":"30","author":"Loibl","year":"2019","journal-title":"Ann. Oncol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1038\/s41523-022-00449-3","article-title":"Tumor Immune Microenvironment of Self-Identified African American and Non-African American Triple Negative Breast Cancer","volume":"8","author":"Marczyk","year":"2022","journal-title":"npj Breast Cancer"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1007\/s10549-022-06630-3","article-title":"The Risk of PD-L1 Expression Misclassification in Triple-Negative Breast Cancer","volume":"194","author":"Aizic","year":"2022","journal-title":"Breast Cancer Res. Treat."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Angelico, G., Broggi, G., Tinnirello, G., Puzzo, L., Vecchio, G.M., Salvatorelli, L., Memeo, L., Santoro, A., Farina, J., and Mul\u00e9, A. (2023). Tumor Infiltrating Lymphocytes (TILS) and PD-L1 Expression in Breast Cancer: A Review of Current Evidence and Prognostic Implications from Pathologist\u2019s Perspective. Cancers, 15.","DOI":"10.20944\/preprints202306.0507.v1"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Li, M., Li, A., Zhou, S., Xu, Y., Xiao, Y., Bi, R., and Yang, W. (2018). Heterogeneity of PD-L1 Expression in Primary Tumors and Paired Lymph Node Metastases of Triple Negative Breast Cancer. BMC Cancer, 18.","DOI":"10.1186\/s12885-017-3916-y"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Yanagihara, K., Nagata, K., Yamakawa, T., Kato, S., Tamura, M., and Yoshida, M. (2025). Decline of PD-L1 Immunoreactivity with Storage Duration in Formalin-Fixed Paraffin-Embedded Breast Cancer Specimens: Implications for Diagnostic Accuracy and Immunotherapy Eligibility in Triple-Negative Breast Cancer. Cancers, 17.","DOI":"10.20944\/preprints202508.1544.v1"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"31347","DOI":"10.18632\/oncotarget.15532","article-title":"Expression of PD-L1 and Prognosis in Breast Cancer: A Metaanalysis","volume":"8","author":"Zhang","year":"2017","journal-title":"Oncotarget"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1038\/s41523-022-00466-2","article-title":"Enhanced Immune Response Outperform Aggressive Cancer Biology and Is Associated with Better Survival in Triple-Negative Breast Cancer","volume":"8","author":"Oshi","year":"2022","journal-title":"npj Breast Cancer"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e985930","DOI":"10.4161\/2162402X.2014.985930","article-title":"Tumor Infiltrating Lymphocytes (TILs) Improve Prognosis in Patients with Triple Negative Breast Cancer (TNBC)","volume":"4","author":"Adams","year":"2015","journal-title":"Oncoimmunology"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1135","DOI":"10.1001\/jama.2024.3056","article-title":"Tumor-Infiltrating Lymphocytes in Triple-Negative Breast Cancer","volume":"331","author":"Jonas","year":"2024","journal-title":"JAMA"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"102257","DOI":"10.1016\/j.ctrv.2021.102257","article-title":"Discordance of PD-L1 Status between Primary and Metastatic Breast Cancer: A Systematic Review and Meta-Analysis","volume":"99","author":"Boman","year":"2021","journal-title":"Cancer Treat. Rev."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"v858","DOI":"10.1093\/annonc\/mdz394.009","article-title":"Performance of PD-L1 Immunohistochemistry (IHC) Assays in Unresectable Locally Advanced or Metastatic Triple-Negative Breast Cancer (MTNBC): Post-Hoc Analysis of IMpassion130","volume":"30","author":"Rugo","year":"2019","journal-title":"Ann. Oncol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e001558","DOI":"10.1136\/jitc-2020-001558","article-title":"Comparison of PD-L1 Protein Expression between Primary Tumors and Metastatic Lesions in Triple Negative Breast Cancers","volume":"8","author":"Rozenblit","year":"2020","journal-title":"J. Immunother. Cancer"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1007\/s10585-018-9950-6","article-title":"Frequent Discordance in PD-1 and PD-L1 Expression between Primary Breast Tumors and Their Matched Distant Metastases","volume":"36","author":"Manson","year":"2019","journal-title":"Clin. Exp. Metastasis"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"5121","DOI":"10.1007\/s10238-023-01190-2","article-title":"Diagnostic Biopsy Does Not Accurately Reflect the PD-L1 Expression in Triple-Negative Breast Cancer","volume":"23","author":"Zdrenka","year":"2023","journal-title":"Clin. Exp. Med."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"549","DOI":"10.1097\/PAI.0000000000001053","article-title":"Tissue Selection for PD-L1 Testing in Triple Negative Breast Cancer (TNBC)","volume":"30","author":"Dobritoiu","year":"2022","journal-title":"Appl. Immunohistochem. Mol. Morphol."}],"container-title":["Cancers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6694\/18\/14\/2182\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T15:51:54Z","timestamp":1783525914000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6694\/18\/14\/2182"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,8]]},"references-count":30,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2026,7]]}},"alternative-id":["cancers18142182"],"URL":"https:\/\/doi.org\/10.3390\/cancers18142182","relation":{},"ISSN":["2072-6694"],"issn-type":[{"value":"2072-6694","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,8]]}}}