{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T17:02:14Z","timestamp":1789578134655,"version":"build-2803163510"},"reference-count":36,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T00:00:00Z","timestamp":1789084800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Int. J. Mol. Sci.","IJMS"],"abstract":"<jats:p>Mesenchymal neoplasms driven by protein kinases represent an increasing group with a broad clinicopathologic and genetic spectrum. Recently, tumors harboring a GAB1::ABL1 fusion have been reported, resulting in constitutive activation of the non-receptor tyrosine kinase ABL1. We describe six cases (one previously reported) investigated by fusion gene analysis and DNA-methylation profiling. Tumors were from three males and three females aged 7\u201371 years and arose in the neck, axilla, lower back, thigh, and digits. Lesions were excised. Available follow-up was uneventful. Neoplasms were circumscribed but unencapsulated, with infiltration of the surrounding tissue, and characterized by haphazardly arranged monomorphous spindle cells. There was a fibromyxoid stroma and staghorn-like vessels were present. Immunohistochemically, expression of CD34 (3\/6), S100 (1\/6), EMA (2\/6), and GLUT1 (3\/3) was observed. All cases harbored a GAB1::ABL1 fusion. RNA expression profile (n = 2) showed high-confidence similarity to dermatofibrosarcoma protuberans (DFSP). DNA-methylation profiling demonstrated that all cases clustered together in close proximity to DFSP. Application of the latest Heidelberg methylation sarcoma classifier did not confidentially classify these neoplasms. However, four showed low-confidence matches to NTRK-rearranged spindle cell neoplasms. GAB1::ABL1 spindle cell neoplasms represent a distinct member of the family of kinase-driven mesenchymal tumors with an indolent clinical course, while the activating ABL1 fusion raises the possibility of targeted therapy in selected cases.<\/jats:p>","DOI":"10.3390\/ijms27188099","type":"journal-article","created":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T13:29:29Z","timestamp":1789133369000},"page":"8099","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Spindle Cell Tumors with a GAB1::ABL1 Fusion\u2014Another Member of Protein-Kinase-Related Soft Tissue Neoplasms: An (Epi)Genetic Study of Six Cases with Benign Behavior"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0332-1673","authenticated-orcid":false,"given":"L. S.","family":"Hiemcke-Jiwa","sequence":"first","affiliation":[{"name":"Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands"},{"name":"Department of Pathology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3434-7937","authenticated-orcid":false,"given":"P.","family":"M\u00fadry","sequence":"additional","affiliation":[{"name":"Department of Pediatric Oncology, University Hospital Brno and Faculty of Medicine, Masaryk University, 66263 Brno, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"E.","family":"Rullo","sequence":"additional","affiliation":[{"name":"Pathology Unit, Department of Laboratories, Bambino Ges\u00f9 Children\u2019s Hospital, IRCCS, 00165 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0873-9638","authenticated-orcid":false,"given":"B.","family":"Koopman","sequence":"additional","affiliation":[{"name":"Department of Pathology, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A. H. G.","family":"Cleven","sequence":"additional","affiliation":[{"name":"Department of Pathology, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J. M.","family":"van Gorp","sequence":"additional","affiliation":[{"name":"Department of Pathology, Location Antonius Hospital, Pathology-DNA, 3435 CM Nieuwegein, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0503-5838","authenticated-orcid":false,"given":"M. M.","family":"van Noesel","sequence":"additional","affiliation":[{"name":"Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R. A.","family":"Schoot","sequence":"additional","affiliation":[{"name":"Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K.","family":"Pol\u00e1\u0161kov\u00e1","sequence":"additional","affiliation":[{"name":"Department of Pediatric Oncology, University Hospital Brno and Faculty of Medicine, Masaryk University, 66263 Brno, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M. L.","family":"Ooft","sequence":"additional","affiliation":[{"name":"Department of Pathology, Location Rijnstate Hospital, Pathology-DNA, 6815 AD Arnhem, The Netherlands"},{"name":"King\u2019s College Hospitals, NHS Foundation Trust, London SE5 9RS, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-0875-2079","authenticated-orcid":false,"given":"N.","family":"Veccia","sequence":"additional","affiliation":[{"name":"Pathology Unit, Department of Oncology and Specialist Medicines, Azienda Ospedaliera San Camillo Forlanini, 00152 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R.","family":"Alaggio","sequence":"additional","affiliation":[{"name":"Pathology Unit, Department of Laboratories, Bambino Ges\u00f9 Children\u2019s Hospital, IRCCS, 00165 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7307-388X","authenticated-orcid":false,"given":"S.","family":"Barresi","sequence":"additional","affiliation":[{"name":"Pathology Unit, Department of Laboratories, Bambino Ges\u00f9 Children\u2019s Hospital, IRCCS, 00165 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1898-1516","authenticated-orcid":false,"given":"S.","family":"Patrizi","sequence":"additional","affiliation":[{"name":"Onco-Hematology, Cell Therapy, Gene Therapies and Hemopoietic Transplant, Bambino Ges\u00f9 Children\u2019s Hospital, IRCCS, 00165 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4747-1032","authenticated-orcid":false,"given":"E.","family":"Miele","sequence":"additional","affiliation":[{"name":"Onco-Hematology, Cell Therapy, Gene Therapies and Hemopoietic Transplant, Bambino Ges\u00f9 Children\u2019s Hospital, IRCCS, 00165 Rome, Italy"},{"name":"UniCamillus-Saint Camillus International University of Health Sciences, 00131 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4958-9819","authenticated-orcid":false,"given":"S.","family":"van Helvert","sequence":"additional","affiliation":[{"name":"Department of Pathology, Radboud Institute for Medical Innovation, Radboud University Medical Center Nijmegen, 6525 GA Nijmegen, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8259-9971","authenticated-orcid":false,"given":"L. 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