{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,21]],"date-time":"2025-08-21T17:37:04Z","timestamp":1755797824490,"version":"3.40.5"},"reference-count":72,"publisher":"Public Library of Science (PLoS)","issue":"5","license":[{"start":{"date-parts":[[2025,5,7]],"date-time":"2025-05-07T00:00:00Z","timestamp":1746576000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Verein zur F\u00f6rderung des Tumorzentrums der Universit\u00e4t Erlangen-N\u00fcrnberg e.V."}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec013\">\n<jats:title>Background<\/jats:title>\n<jats:p>The tumor microenvironment is crucial for prognosis and response to immunotherapy in several tumor entities.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec014\">\n<jats:title>Methods<\/jats:title>\n<jats:p>In a multicenter retrospective study, a total of 86 tumor samples from patients with metastatic melanoma were evaluated for baseline expression of indoleamine 2,3-dioxygenase (IDO) and programmed death ligand 1 (PD-L1). Expression patterns of IDO and PD-L1 on tumor cells and antigen-presenting cells (APCs) as determined by immunohistochemical (IHC) staining of paraffin-embedded tissue sections were correlated with response to ipilimumab and overall survival (OS). Statistical analysis was performed using the Spearman correlation, the Mann-Whitney test and Kaplan-Meier estimator.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec015\">\n<jats:title>Results<\/jats:title>\n<jats:p>IDO expression in tumor cells or APCs was not predictive for treatment response. The median OS was 26 months in IDO-positive and IDO-negative patients, regardless of IDO expression in tumor cells or APCs. A correlation of IHC expression scores of IDO and PD-L1 could not be documented.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec016\">\n<jats:title>Conclusion<\/jats:title>\n<jats:p>The exact role of IDO in creating an immunosuppressive tumor environment and its reversal needs to be further elucidated.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pone.0321937","type":"journal-article","created":{"date-parts":[[2025,5,7]],"date-time":"2025-05-07T20:21:07Z","timestamp":1746649267000},"page":"e0321937","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":3,"title":["Prognostic and predictive value of IDO expression in metastatic melanoma treated with Ipilimumab"],"prefix":"10.1371","volume":"20","author":[{"given":"Dagmar","family":"von Bubnoff","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9592-2347","authenticated-orcid":true,"given":"Christina","family":"Schmitt","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simone M.","family":"Goldinger","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dirk","family":"Schadendorf","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katharina C.","family":"K\u00e4hler","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christian","family":"Hafner","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nora","family":"Kramer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Waltraud","family":"Fr\u00f6hlich","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2279-6906","authenticated-orcid":true,"given":"Reinhard","family":"Dummer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carola","family":"Berking","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stefan","family":"Schliep","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael 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