{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T00:08:20Z","timestamp":1787875700019,"version":"build-2784847793"},"reference-count":12,"publisher":"American Medical Association (AMA)","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA Dermatol"],"published-print":{"date-parts":[[2026,1,1]]},"abstract":"\n Importance<\/jats:title>\n \n Janus kinase 2 (\n JAK2<\/jats:italic>\n ) gene fusions characterize cytotoxic cutaneous T-cell lymphoma (CTCL) including primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma (pcAETCL). The identification of these fusions is rarely reported in indolent CTCL.\n <\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n To characterize patients with CTCL to better understand the diagnostic, prognostic, and therapeutic significance of this molecular alteration in CTCL.<\/jats:p>\n <\/jats:sec>\n \n Design, Setting, and Participants<\/jats:title>\n \n A retrospective case series of patients with CTCL with\n JAK2<\/jats:italic>\n fusions identified between the years 2000 and 2025. Fusions were identified by a custom RNA sequencing panel and by a targeted hybrid-capture-based next-generation DNA sequencing-based panel. The study included a single referral cancer center in the US.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Overall, 43 patients (12 female [27.9%] and 31 male individuals [72.1%]; median [range] age, 45 [16-65] years) with CTCL who were found to have\n JAK2<\/jats:italic>\n gene fusions during evaluation and follow-up were included. Thirty-eight of the 43 identified patients (88.4%) with fusions of\n JAK2<\/jats:italic>\n and 10 different gene partners (most frequently\n ATXN2L<\/jats:italic>\n ,\n CAPRIN1,<\/jats:italic>\n and\n PCM1<\/jats:italic>\n ) had mycosis fungoides (MF), CD30-positive lymphoproliferative disorders (LPD), or overlap presentations, whereas 4 pcAETCL and 1 peripheral T-cell lymphoma not otherwise specified were identified. Secondary genetic events included mutations of epigenetic and transcriptional regulators. Neither mutational burden, type, or fusion partner distinguished cases with early-stage or aggressive CTCL.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusions and Relevance<\/jats:title>\n \n This case series found that\n JAK2<\/jats:italic>\n fusions were seen in aggressive cytotoxic CTCL as well as in T-cell lymphomas with more indolent behavior, possibly representing a precursor lesion to aggressive evolution with age and comorbidities. The prominence of these fusions supports a potentially larger role for JAK2 targeting in patients with early-stage MF, CD30-positive LPD, or overlap presentations.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.1001\/jamadermatol.2025.4688","type":"journal-article","created":{"date-parts":[[2025,11,26]],"date-time":"2025-11-26T16:31:37Z","timestamp":1764174697000},"page":"41","source":"Crossref","is-referenced-by-count":5,"title":["JAK2 Fusions in Adult Patients With Mycosis Fungoides and CD30 Lymphoproliferative Disorders"],"prefix":"10.1001","volume":"162","author":[{"given":"Shamir","family":"Geller","sequence":"first","affiliation":[{"name":"Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"},{"name":"Department of Dermatology, Weill Cornell Medicine, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Viviane","family":"Liao","sequence":"additional","affiliation":[{"name":"Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leore","family":"Lavin","sequence":"additional","affiliation":[{"name":"Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"},{"name":"Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haiming","family":"Tang","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mia","family":"Do","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrea","family":"Moy","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cesar A.","family":"Virgen","sequence":"additional","affiliation":[{"name":"Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liam","family":"Donnelly","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Melissa P.","family":"Pulitzer","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York"},{"name":"Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"10","reference":[{"issue":"2","key":"doi250057r1","doi-asserted-by":"publisher","first-page":"180","DOI":"10.1182\/blood.2022016690","article-title":"Malignant T cells induce skin barrier defects through cytokine-mediated JAK\/STAT signaling in cutaneous T-cell lymphoma.","volume":"141","author":"Gluud","year":"2023","journal-title":"Blood"},{"issue":"3","key":"doi250057r2","doi-asserted-by":"publisher","first-page":"702","DOI":"10.3324\/haematol.2020.274506","article-title":"Deregulation of JAK2 signaling underlies primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma.","volume":"107","author":"Bastidas 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