{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,14]],"date-time":"2026-01-14T16:11:33Z","timestamp":1768407093317,"version":"3.49.0"},"reference-count":9,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2024,5,1]],"date-time":"2024-05-01T00:00:00Z","timestamp":1714521600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2024,5,1]],"date-time":"2024-05-01T00:00:00Z","timestamp":1714521600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["J Med Case Reports"],"abstract":"<jats:title>Abstract<\/jats:title><jats:sec>\n                <jats:title>Background<\/jats:title>\n                <jats:p>Pembrolizumab (PEM), an immune checkpoint inhibitor (ICI), is often used for triple-negative breast cancer, but can also be used to treat solid tumors that exhibit high microsatellite instability (MSI-High). However, patients with breast cancer rarely have MSI-High, the use of PEM in such cases in clinical practice is uncertain due to lack of sufficient supporting data. Here, we report the case of a premenopausal woman in who received PEM for MSI-High luminal-type breast cancer.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Case presentation<\/jats:title>\n                <jats:p>A 40-year-old premenopausal Asian woman was diagnosed with stage IIA (T2N0M0) breast cancer and had an Oncotype DX recurrence score of 38. After surgery, she received 4 courses of chemotherapy with docetaxel and cyclophosphamide. After 3\u00a0months of tamoxifen therapy, the patient complained of abdominal pain due to right iliac metastasis, and biopsy of the metastatic lesion showed of luminal type; she was sequentially treated with fulvestrant, a CDK4\/6 inhibitor, and an anticancer drug (TS1), but over the next year, metastasis to the bone and para-aortic lymph nodes increased. Tumor was MSI-High; PEM was started, and after three courses, bone metastases were reduced, para-aortic lymph node metastases resolved, opioids were discontinued, and the patient returned to society; PEM was administered for 1\u00a0year with no worsening of bone metastases on imaging. Asymptomatic brain metastasis less than 1\u00a0cm was detected and gamma knife was performed. Six months after completion of PEM, the patient is working with no new lesions.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusion<\/jats:title>\n                <jats:p>We report a case of luminal-type breast cancer with bone metastases and MSI-High, which was treated with PEM and showed a rapid therapeutic response.<\/jats:p>\n              <\/jats:sec>","DOI":"10.1186\/s13256-024-04522-2","type":"journal-article","created":{"date-parts":[[2024,5,1]],"date-time":"2024-05-01T00:02:12Z","timestamp":1714521732000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Pembrolizumab response in stage IV luminal-type breast cancer with high microsatellite instability: a case report"],"prefix":"10.1186","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-0924-798X","authenticated-orcid":false,"given":"Keiko","family":"Inakami","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Noriko","family":"Fujita","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chikage","family":"Iguchi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yukie","family":"Enomoto","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Junya","family":"Minohata","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Atsushi","family":"Sata","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoshimasa","family":"Miyagawa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tetsu","family":"Yanagisawa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tomokazu","family":"Saitoh","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takashi","family":"Nomura","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuka","family":"Sawai","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keiko","family":"Takahara","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tsutomu","family":"Kasugai","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eiichi","family":"Shiba","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2024,5,1]]},"reference":[{"issue":"7","key":"4522_CR1","doi-asserted-by":"publisher","first-page":"567","DOI":"10.1007\/s12272-019-01140-1","volume":"42","author":"HD Kim","year":"2019","unstructured":"Kim HD, Park SH. Immunological and clinical implications of immune checkpoint blockade in human cancer. Arch Pharm Res. 2019;42(7):567\u201381.","journal-title":"Arch Pharm Res"},{"issue":"13","key":"4522_CR2","doi-asserted-by":"publisher","first-page":"3015","DOI":"10.1084\/jem.20090847","volume":"206","author":"LM Francisco","year":"2009","unstructured":"Francisco LM, Salinas VH, Brown KE, Vanguri VK, Freeman GJ, Kuchroo VK, et al. PD-L1 regulates the development, maintenance, and function of induced regulatory T cells. J Exp Med. 2009;206(13):3015\u201329.","journal-title":"J Exp Med"},{"issue":"1","key":"4522_CR3","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1200\/JCO.19.02105","volume":"38","author":"A Marabelle","year":"2020","unstructured":"Marabelle A, Le DT, Ascierto PA, Ascierto PA, Giacomo AMD, Jesus-Acosta AD, et al. Efficacy of pembrolizumab in patients with noncolorectal high microsatellite instability\/mismatch repair-deficient cancer: results from the phase II KEYNOTE-158 study. J Clin Oncol. 2020;38(1):1\u201310.","journal-title":"J Clin Oncol"},{"issue":"23","key":"4522_CR4","doi-asserted-by":"publisher","first-page":"7035","DOI":"10.1158\/1078-0432.CCR-19-1324","volume":"25","author":"J Willis","year":"2019","unstructured":"Willis J, Lefterova MI, Artyomenko A, Kasi PM, Nakamura Y, Mody K, et al. Validation of microsatellite instability detection using a comprehensive plasma-based genotyping panel. Clin Cancer Res. 2019;25(23):7035\u201345.","journal-title":"Clin Cancer Res"},{"issue":"1","key":"4522_CR5","doi-asserted-by":"publisher","first-page":"20175","DOI":"10.1038\/s41598-021-99726-7","volume":"11","author":"B Zengel","year":"2021","unstructured":"Zengel B, Kilic M, Tasli F, Simsek C, Karatas M, Ozdemir O, Cavdar D, Durusoy R, Bas KK, Uslu A. Breast cancer patients with isolated bone metastases and oligometastatic bone disease show different survival outcomes. Sci Rep. 2021;11(1):20175.","journal-title":"Sci Rep"},{"issue":"4","key":"4522_CR6","doi-asserted-by":"publisher","first-page":"286","DOI":"10.1200\/JCO.18.00283","volume":"37","author":"A Latham","year":"2019","unstructured":"Latham A, Srinivasan P, Kemel Y, Shia J, Bandlamudi C, Mandelker D, et al. Microsatellite instability is associated with the presence of Lynch syndrome pan-cancer. J Clin Oncol. 2019;37(4):286\u201395.","journal-title":"J Clin Oncol"},{"issue":"1","key":"4522_CR7","doi-asserted-by":"publisher","first-page":"117","DOI":"10.1038\/s41523-022-00490-2","volume":"8","author":"N Vidula","year":"2022","unstructured":"Vidula N, Lipman A, Kato S, Weipert C, Hesler K, Azzi G, Elkhanany A, Juric D, Rodriguez E, Faulkner C, Makhlouf P, Price K, O\u2019shanghnessy J, Bardia A. Detection of microsatellite instability high (MSI-H) status by targeted plasma-based genotyping in metastatic breast cancer. Npj Breast Cancer. 2022;8(1):117.","journal-title":"Npj Breast Cancer"},{"issue":"3","key":"4522_CR8","doi-asserted-by":"publisher","first-page":"e252","DOI":"10.1097\/RLU.0000000000003950","volume":"47","author":"A Kawamata","year":"2022","unstructured":"Kawamata A, Sasada S, Emi A, Masumoto N, Kadoya T. Monitoring of programmed cell death ligand-1 blockade using FDG PET\/CT for microsatellite instability-high metastatic breast cancer. Clin Nucl Med. 2022;47(3):e252\u20133.","journal-title":"Clin Nucl Med"},{"issue":"49","key":"4522_CR9","doi-asserted-by":"publisher","first-page":"5289","DOI":"10.1038\/s41388-022-02504-6","volume":"41","author":"KZ Klouch","year":"2022","unstructured":"Klouch KZ, Stern MH, Trabelsi-Grati O, Kiavue N, Cabel L, Silveira AB, et al. Microsatellite instability detection in breast cancer using drop-off droplet digital PCR. Oncogene. 2022;41(49):5289\u201397.","journal-title":"Oncogene"}],"container-title":["Journal of Medical Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s13256-024-04522-2.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1186\/s13256-024-04522-2\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/s13256-024-04522-2.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,5,1]],"date-time":"2024-05-01T00:09:06Z","timestamp":1714522146000},"score":1,"resource":{"primary":{"URL":"https:\/\/jmedicalcasereports.biomedcentral.com\/articles\/10.1186\/s13256-024-04522-2"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,5,1]]},"references-count":9,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2024,12]]}},"alternative-id":["4522"],"URL":"https:\/\/doi.org\/10.1186\/s13256-024-04522-2","relation":{},"ISSN":["1752-1947"],"issn-type":[{"value":"1752-1947","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,5,1]]},"assertion":[{"value":"15 November 2023","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"24 March 2024","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"1 May 2024","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"All procedures performed in this study involving the human participant were in accordance with the ethical standards of the institutional and\/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval and consent to participate"}},{"value":"Informed consent was obtained from the participant in this study.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Informed consent"}},{"value":"Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}},{"value":"The authors declare that they have no conflict of interest.","order":5,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"214"}}