{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,24]],"date-time":"2026-10-24T00:37:35Z","timestamp":1792802255917,"version":"4.5.0"},"reference-count":34,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T00:00:00Z","timestamp":1792713600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"},{"start":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T00:00:00Z","timestamp":1792713600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Vet Comparative Oncology"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    Studies describing feline myeloma related diseases (MRD) are limited and reported prognostic indicators are inconsistent. Cats more commonly exhibit visceral plasma cell tumours (PCTs) than marrow\u2010predominant disease, suggesting that diagnostic approaches adapted from the International Myeloma Working Group (IMWG) criteria, incorporating extramedullary involvement and myeloma defining events (MDEs), may better capture clinically relevant disease. We sought to evaluate cats with serum protein electrophoresis (SPE) and immunofixation (IF) confirmed M\u2010proteins using IMWG\u2010adapted criteria, determine how often cases satisfy IMWG\u2010adapted versus classic multiple myeloma (MM) definitions, compare outcomes, characterize clinical and laboratory findings and assess prognostic indicators. A retrospective cohort of 20 cats with SPE\/IF\u2010confirmed M\u2010proteins and clinical data was included in the study applying IMWG\u2010adapted and classic MM criteria using available clinical records, laboratory data and cytologic or histologic findings. Survival was evaluated using the log\u2010rank test. 14\/20 cats met IMWG\u2010adapted MM criteria, whereas 7 cats met classic criteria. Median survival time did not differ between classic MM (226.5\u2009days) and IMWG\u2010reclassified MM (141\u2009days;\n                    <jats:italic>p<\/jats:italic>\n                    \u2009=\u20090.99). Visceral organ involvement was common; splenic PCTs occurred in 71.4% (10\/14) and hepatic PCTs in 87.5% (7\/8) of sampled organs. Lytic bone lesions were infrequent (3\/14). IgG M\u2010proteins predominated (71.4%). No clinicopathologic variable was significantly associated with survival. IMWG\u2010adapted criteria reclassified MM without altering survival, supporting their diagnostic utility in feline MRD. The predominance of visceral PCTs and infrequent bone involvement highlights species\u2010specific disease patterns and the diagnostic value of extramedullary sampling. Larger prospective studies should refine feline\u2010specific biomarkers and validate MDEs.\n                  <\/jats:p>","DOI":"10.1111\/vco.70123","type":"journal-article","created":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T23:40:47Z","timestamp":1792798847000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Retrospective Application of the Current International Myeloma Working Group Disease Definitions in 20 Cats With Immunoglobulin Secreting Neoplasms"],"prefix":"10.1111","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6899-8255","authenticated-orcid":false,"given":"Christina M.","family":"Jeffries","sequence":"first","affiliation":[{"name":"Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences Colorado State University  Fort Collins Colorado USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9471-886X","authenticated-orcid":false,"given":"R. Adam","family":"Harris","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences Colorado State University  Fort Collins Colorado USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-7832-4832","authenticated-orcid":false,"given":"Kathryn","family":"Vickery","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences Colorado State University  Fort Collins Colorado USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul R.","family":"Avery","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences Colorado State University  Fort Collins Colorado USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9234-0082","authenticated-orcid":false,"given":"Sangeeta","family":"Rao","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences Colorado State University  Fort Collins Colorado USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4904-8788","authenticated-orcid":false,"given":"A Russell","family":"Moore","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences Colorado State University  Fort Collins Colorado USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,10,23]]},"reference":[{"issue":"6","key":"e_1_2_9_2_1","doi-asserted-by":"crossref","first-page":"1376","DOI":"10.1111\/j.1939-1676.2006.tb00754.x","article-title":"Myeloma\u2010Related Disorders in Cats Commonly Present as Extramedullary Neoplasms in Contrast to Myeloma in Human Patients: 24 Cases With Clinical Follow\u2010Up","volume":"20","author":"Mellor P. J.","year":"2006","journal-title":"Journal of Veterinary Internal Medicine"},{"issue":"3","key":"e_1_2_9_3_1","doi-asserted-by":"crossref","first-page":"e203","DOI":"10.1016\/S2352-3026(22)00386-6","article-title":"Personalised Progression Prediction in Patients With Monoclonal Gammopathy of Undetermined Significance or Smouldering Multiple Myeloma (PANGEA): A Retrospective, Multicohort Study","volume":"10","author":"Cowan A.","year":"2023","journal-title":"Lancet Haematology"},{"key":"e_1_2_9_4_1","first-page":"688","volume-title":"Withrow and Macewen's Small Animal Clinical Oncology","author":"Vail D. M.","year":"2020"},{"issue":"4","key":"e_1_2_9_5_1","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1111\/j.1939-165X.2005.tb00059.x","article-title":"Multiple Myeloma in 16 Cats: A Retrospective Study","volume":"34","author":"Patel R. T.","year":"2005","journal-title":"Veterinary Clinical Pathology"},{"issue":"3","key":"e_1_2_9_6_1","doi-asserted-by":"crossref","first-page":"1693","DOI":"10.1111\/jvim.17051","article-title":"Descriptive Analysis and Prognostic Factors in Cats With Myeloma\u2010Related Disorders: A Multicenter Retrospective Study of 50 Cases","volume":"38","author":"Lecot L.","year":"2024","journal-title":"Journal of Veterinary Internal Medicine"},{"issue":"1","key":"e_1_2_9_7_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s13045-017-0549-1","article-title":"Diagnosis, Treatment, and Response Assessment in Solitary Plasmacytoma: Updated Recommendations From a European Expert Panel","volume":"11","author":"Caers J.","year":"2018","journal-title":"Journal of Hematology & Oncology"},{"key":"e_1_2_9_8_1","first-page":"668","volume-title":"Withrow and Macewen's Small Animal Clinical Oncology","author":"Vail D. M.","year":"2020"},{"key":"e_1_2_9_9_1","doi-asserted-by":"crossref","first-page":"151449","DOI":"10.1016\/j.anndiagpath.2019.151449","article-title":"IgA Plasma Cell Neoplasms Are Characterized by Poorer Long\u2010Term Survival and Increased Genomic Complexity Compared to IgG Neoplasms","volume":"44","author":"Habermehl G. K.","year":"2020","journal-title":"Annals of Diagnostic Pathology"},{"issue":"4","key":"e_1_2_9_10_1","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1354\/vp.37-4-364","article-title":"Multiple Myeloma in Cats: Variable Presentation With Different Immunoglobulin Isotypes in Two Cats","volume":"37","author":"Bienzle D.","year":"2000","journal-title":"Veterinary Pathology"},{"issue":"1","key":"e_1_2_9_11_1","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1111\/vcp.12760","article-title":"Protein Characterization Using Electrophoresis and Immunofixation; a Case\u2010Based Review of Dogs and Cats","volume":"48","author":"Moore A. R.","year":"2019","journal-title":"Veterinary Clinical Pathology"},{"issue":"1","key":"e_1_2_9_12_1","doi-asserted-by":"crossref","first-page":"551","DOI":"10.1182\/hematology.2022000355","article-title":"The Consultant's Guide to Smoldering Multiple Myeloma","volume":"2022","author":"Thorsteinsdottir S.","year":"2022","journal-title":"Hematology. American Society of Hematology. Education Program"},{"issue":"1","key":"e_1_2_9_13_1","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1182\/asheducation-2015.1.272","article-title":"Evolving Diagnostic Criteria for Multiple Myeloma","volume":"2015","author":"Rajkumar S. V.","year":"2015","journal-title":"Hematology. American Society of Hematology. Education Program"},{"key":"e_1_2_9_14_1","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.clinbiochem.2017.10.013","article-title":"Candidate Recommendations for Protein Electrophoresis Reporting From the Canadian Society of Clinical Chemists Monoclonal Gammopathy Working Group","volume":"51","author":"Booth R. A.","year":"2018","journal-title":"Clinical Biochemistry"},{"issue":"2","key":"e_1_2_9_15_1","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1354\/vp.45-2-159","article-title":"Histopathologic, Immunohistochemical, and Cytologic Analysis of Feline Myeloma\u2010Related Disorders: Further Evidence for Primary Extramedullary Development in the Cat","volume":"173","author":"Mellor P. J.","year":"2008","journal-title":"Veterinary Pathology"},{"issue":"9","key":"e_1_2_9_16_1","doi-asserted-by":"crossref","first-page":"1802","DOI":"10.1002\/ajh.27422","article-title":"Multiple Myeloma: 2024 Update on Diagnosis, Risk\u2010Stratification, and Management","volume":"99","author":"Rajkumar S. V.","year":"2024","journal-title":"American Journal of Hematology"},{"issue":"5","key":"e_1_2_9_17_1","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1016\/j.jfms.2004.12.005","article-title":"Multiple Myelomas in Cats","volume":"7","author":"Hanna F.","year":"2005","journal-title":"Journal of Feline Medicine and Surgery"},{"issue":"2","key":"e_1_2_9_18_1","doi-asserted-by":"crossref","first-page":"1031","DOI":"10.1111\/jvim.16070","article-title":"Light Chain Myeloma and Detection of Serum and Urine Free Light Chains in Veterinary Patients","volume":"35","author":"Harris R. A.","year":"2021","journal-title":"Journal of Veterinary Internal Medicine"},{"issue":"1","key":"e_1_2_9_19_1","doi-asserted-by":"crossref","first-page":"442","DOI":"10.1111\/jvim.15967","article-title":"Retrospective Evaluation of the Use of the International Myeloma Working Group Response Criteria in Dogs With Secretory Multiple Myeloma","volume":"35","author":"Moore A. R.","year":"2021","journal-title":"Journal of Veterinary Internal Medicine"},{"issue":"4","key":"e_1_2_9_20_1","doi-asserted-by":"crossref","first-page":"941","DOI":"10.1038\/leu.2012.296","article-title":"Serum Free Light Chain Ratio as a Biomarker for High\u2010Risk Smoldering Multiple Myeloma","volume":"27","author":"Larsen J. T.","year":"2013","journal-title":"Leukemia"},{"issue":"3","key":"e_1_2_9_21_1","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1111\/vco.12905","article-title":"Mass Spectrometric\u2010Based Assessment of the Serum Kappa to Lambda Immunoglobulin Light Chain Ratio (\u03ba:\u03bb) in Dogs With Immunoglobulin Secretory Diseases","volume":"21","author":"Moore A. R.","year":"2023","journal-title":"Veterinary and Comparative Oncology"},{"issue":"1","key":"e_1_2_9_22_1","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1111\/vcp.12766","article-title":"Validation and Method Comparison of the Use of Densitometry to Quantify Monoclonal Proteins in Canine Sera","volume":"48","author":"Harris A. 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Clinically Benign Cases Showing Transition to Malignant Plasmacytomas After Long Periods of Observation","volume":"19","author":"Bernett A.","year":"1986","journal-title":"Clinical Biochemistry"},{"issue":"4","key":"e_1_2_9_26_1","first-page":"170","article-title":"Biochemical Abnormalities in Multiple Myeloma","volume":"40","author":"Choo\u2010Kang E.","year":"1991","journal-title":"West Indian Medical Journal"},{"issue":"2","key":"e_1_2_9_27_1","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1111\/vcp.12940","article-title":"Diagnostic Performance of Routine Electrophoresis and Immunofixation for Detection of Immunoglobulin Paraproteins (M\u2010Proteins) in Dogs With Multiple Myeloma and Related Disorders: Part 2 \u2013 Toward Improved Diagnostic Performance","volume":"50","author":"Moore A. R.","year":"2021","journal-title":"Veterinary Clinical Pathology"},{"issue":"3","key":"e_1_2_9_28_1","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1182\/blood.2024025415","article-title":"Comparison of Progression Risk of Monoclonal Gammopathy of Undetermined Significance by Method of Detection","volume":"145","author":"Visram A.","year":"2025","journal-title":"Blood"},{"issue":"5","key":"e_1_2_9_29_1","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1177\/0300985818771151","article-title":"Urothelial Carcinomas of the Urinary Bladder With Plasmacytoid or Rhabdoid Features and Tendency of Epithelial\u2010Mesenchymal Transition in 3 Dogs","volume":"55","author":"Lin S. J. H.","year":"2018","journal-title":"Veterinary Pathology"},{"issue":"1","key":"e_1_2_9_30_1","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1016\/j.rce.2014.07.003","article-title":"Gammapat\u00edas Biclonales: Estudio Retrospectivo de 47 Pacientes [Biclonal Gammopathies: A Retrospective Study of 47 Patients]","volume":"215","author":"Garc\u00eda\u2010Garc\u00eda P.","year":"2015","journal-title":"Revista Cl\u00ednica Espa\u00f1ola"},{"issue":"8","key":"e_1_2_9_31_1","doi-asserted-by":"crossref","first-page":"713","DOI":"10.1177\/1098612X13519632","article-title":"Co\u2010Infection With \n                     Anaplasma platys\n                  , \n                     Bartonella henselae\n                  , Bartonella Koehlerae and \u201cCandidatus Mycoplasma Haemominutum\u201d in a Cat Diagnosed With Splenic Plasmacytosis and Multiple Myeloma","volume":"16","author":"Qurollo B. A.","year":"2014","journal-title":"Journal of Feline Medicine and Surgery"},{"issue":"2","key":"e_1_2_9_32_1","doi-asserted-by":"crossref","first-page":"e143","DOI":"10.1016\/S2352-3026(21)00283-0","article-title":"Consensus Guidelines and Recommendations for Infection Prevention in Multiple Myeloma: A Report From the International Myeloma Working Group","volume":"9","author":"Raje N. S.","year":"2022","journal-title":"Lancet Haematology"},{"issue":"8","key":"e_1_2_9_33_1","doi-asserted-by":"crossref","first-page":"643","DOI":"10.1016\/j.jfms.2010.03.018","article-title":"Serum Protein Electrophoresis in 155 Cats","volume":"12","author":"Taylor S. S.","year":"2010","journal-title":"Journal of Feline Medicine and Surgery"},{"issue":"6","key":"e_1_2_9_34_1","doi-asserted-by":"crossref","first-page":"854","DOI":"10.3324\/haematol.2011.054015","article-title":"Monoclonal Gammopathy of Undetermined Significance and Risk of Infections: A Population\u2010Based Study","volume":"97","author":"Kristinsson S. Y.","year":"2012","journal-title":"Haematologica"},{"issue":"4","key":"e_1_2_9_35_1","doi-asserted-by":"crossref","first-page":"420","DOI":"10.1111\/vcp.13399","article-title":"Evaluation of Serum Protein Electrophoresis and Immunofixation in Dogs Seropositive for Various Vector\u2010Borne Pathogens","volume":"53","author":"Jornet\u2010Rius O.","year":"2024","journal-title":"Veterinary Clinical Pathology"}],"container-title":["Veterinary and Comparative Oncology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/vco.70123","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/vco.70123","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/vco.70123","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T23:40:51Z","timestamp":1792798851000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/vco.70123"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10,23]]},"references-count":34,"alternative-id":["10.1111\/vco.70123"],"URL":"https:\/\/doi.org\/10.1111\/vco.70123","archive":["Portico"],"relation":{},"ISSN":["1476-5810","1476-5829"],"issn-type":[{"value":"1476-5810","type":"print"},{"value":"1476-5829","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10,23]]},"assertion":[{"value":"2026-04-18","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-09-24","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-10-23","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"vco.70123"}}