{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T03:09:01Z","timestamp":1780369741337,"version":"3.54.1"},"reference-count":16,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T00:00:00Z","timestamp":1772668800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T00:00:00Z","timestamp":1772668800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100012094","name":"F\u00e9d\u00e9ration Enfants Cancers Sant\u00e9","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100012094","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100007394","name":"Association Laurette Fugain","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100007394","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001677","name":"Institut National de la Sant\u00e9 et de la Recherche M\u00e9dicale","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001677","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012095","name":"Les 111 des Arts","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100012095","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004099","name":"Ligue Contre le Cancer","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004099","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["eJHaem"],"published-print":{"date-parts":[[2026,4]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Histiocytic sarcoma (HS) is a rare neoplasm derived from non\u2010Langerhans histiocytic cells, exceptionally arising from B\u2010ALL.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We present the case of a child with high\u2010risk B\u2010ALL with PAX5 P80R mutation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Despite initial remission, a chemoresistant paravertebral mass was identified as HS. A shared IGK\/TCRB rearrangements and PAX5 alterations between the leukaemic and histiocytic clones suggested transdifferentiation driven by PAX5. A somatic MAP2K1 mutation in the HS component prompted selumetinib treatment, leading to a rapid response.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This case underscores the role of PAX5 in lineage plasticity and highlights the potential of targeted MEK inhibition in MAPK\u2010driven HS arising from B\u2010ALL.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Trial Registration<\/jats:title>\n                    <jats:p>The authors have confirmed clinical trial registration is not needed for this submission<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/jha2.70216","type":"journal-article","created":{"date-parts":[[2026,3,8]],"date-time":"2026-03-08T23:22:22Z","timestamp":1773012142000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Selumetinib as an Effective Therapy of Histiocytic Sarcoma Evolving From a B\u2010Cell Acute Lymphoblastic Leukaemia"],"prefix":"10.1002","volume":"7","author":[{"given":"Laetitia","family":"Largeaud","sequence":"first","affiliation":[{"name":"Laboratory of Hematology Institut Universitaire du Cancer de Toulouse, CHU Toulouse  Toulouse France"},{"name":"Universit\u00e9 De Toulouse, Inserm, Centre National de la Recherche Scientifique, Universit\u00e9 Toulouse III\u2010Paul Sabatier Centre de Recherches en Canc\u00e9rologie de Toulouse  Toulouse France"},{"name":"Equipe Labellis\u00e9e Ligue Contre le Cancer 2023  Toulouse France"},{"name":"Equipe Labellis\u00e9e Institut Carnot Opale  Toulouse France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charlotte","family":"Syrykh","sequence":"additional","affiliation":[{"name":"Laboratory of Anatomo\u2010Pathology Institut Universitaire du Cancer de Toulouse, CHU Toulouse  Toulouse France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julie","family":"Vial","sequence":"additional","affiliation":[{"name":"Department of Pediatric Radiology CHU Toulouse  Toulouse France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1609-3307","authenticated-orcid":false,"given":"Alban","family":"Canali","sequence":"additional","affiliation":[{"name":"Laboratory of Hematology Institut Universitaire du Cancer de Toulouse, CHU Toulouse  Toulouse France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isabelle","family":"Luquet","sequence":"additional","affiliation":[{"name":"Laboratory of Hematology Institut Universitaire du Cancer de Toulouse, CHU Toulouse  Toulouse France"},{"name":"Universit\u00e9 De Toulouse, Inserm, Centre National de la Recherche Scientifique, Universit\u00e9 Toulouse III\u2010Paul Sabatier Centre de Recherches en Canc\u00e9rologie de Toulouse  Toulouse France"},{"name":"Equipe Labellis\u00e9e Ligue Contre le Cancer 2023  Toulouse France"},{"name":"Equipe Labellis\u00e9e Institut Carnot Opale  Toulouse France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fran\u00e7ois","family":"Vergez","sequence":"additional","affiliation":[{"name":"Laboratory of Hematology Institut Universitaire du Cancer de Toulouse, CHU Toulouse  Toulouse France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"St\u00e9phanie","family":"Dufrechou","sequence":"additional","affiliation":[{"name":"Laboratory of Hematology Institut Universitaire du Cancer de Toulouse, CHU Toulouse  Toulouse France"},{"name":"Universit\u00e9 De Toulouse, Inserm, Centre National de la Recherche Scientifique, Universit\u00e9 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