{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,11]],"date-time":"2026-03-11T14:17:18Z","timestamp":1773238638152,"version":"3.50.1"},"reference-count":56,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2025,7,10]],"date-time":"2025-07-10T00:00:00Z","timestamp":1752105600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Vienna\u2019s Spanish Riding School, Austria"},{"name":"University of Veterinary Medicine Vienna"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Malignant melanoma (MM) affects not only humans but also animals, with gray horses being particularly predisposed to acquiring the disease. Multiomics have greatly advanced the understanding of human MM. In contrasty little is known regarding the pathogenesis of gray-horse melanoma and the unique phenomenon of melanoma \u201cdormancy\u201d in some animals. To help close this gap in knowledge, melanoma tissue and intact skin collected from gray horses were subjected to transcriptome analysis using RNAseq. In the next step, cultured primary tumor cells and normal skin fibroblasts were established from gray horses, and their protein expression profiles were determined. The obtained data unambiguously identified gray-horse melanoma (ghM) as a malignant tumor, as reflected by the overrepresentation of pathways typically activated in human melanoma and other human cancers. These included the RAS\/RAF\/MAPK, the IRS\/IGF1R, and the PI3K\/AKT signaling networks. In addition, the obtained data suggest that the key molecules RAC1, RAS, and BRAF, which are frequently mutated in human melanoma, may also contain activating mutations in ghM, whilst PTEN may harbor loss-of-function mutations. This issue will be subject to downstream analyses determining the mutational status in ghM to further advance the understanding of this frequent disease in gray horses.<\/jats:p>","DOI":"10.3390\/ijms26146620","type":"journal-article","created":{"date-parts":[[2025,7,11]],"date-time":"2025-07-11T12:46:33Z","timestamp":1752237993000},"page":"6620","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Gray-Horse Melanoma\u2014A Wolf in Sheep\u2019s Clothing"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0558-7889","authenticated-orcid":false,"given":"Daniela M.","family":"Brodesser","sequence":"first","affiliation":[{"name":"Research Group Oncology (RGO), Centre for Equine Health and Research, Department for Small Animals and Horses, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karin","family":"Schlangen","sequence":"additional","affiliation":[{"name":"Section for Biosimulation and Bioinformatics, Centre for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna (MUV), Waehringer Guertel 18-20, 1090 Vienna, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4119-8127","authenticated-orcid":false,"given":"Alexandro","family":"Rodr\u00edguez-Rojas","sequence":"additional","affiliation":[{"name":"Division of Small Animal Internal Medicine, Department for Small Animals and Horses, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5088-6346","authenticated-orcid":false,"given":"Benno","family":"Kuropka","sequence":"additional","affiliation":[{"name":"Institute of Chemistry and Biochemistry, Freie Universit\u00e4t Berlin, 14195 Berlin, Germany"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8731-2936","authenticated-orcid":false,"given":"Pavlos G.","family":"Doulidis","sequence":"additional","affiliation":[{"name":"Division of Small Animal Internal Medicine, Department for Small Animals and Horses, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3837-3422","authenticated-orcid":false,"given":"Sabine","family":"Brandt","sequence":"additional","affiliation":[{"name":"Research Group Oncology (RGO), Centre for Equine Health and Research, Department for Small Animals and Horses, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5291-1365","authenticated-orcid":false,"given":"Barbara","family":"Pratscher","sequence":"additional","affiliation":[{"name":"Division of Small Animal Internal Medicine, Department for Small Animals and Horses, University of Veterinary Medicine, Veterinaerplatz 1, 1210 Vienna, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1007\/978-3-319-22539-5_2","article-title":"Melanoma Epidemiology and Prevention","volume":"167","author":"Berwick","year":"2016","journal-title":"Cancer Treat. Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"685","DOI":"10.1002\/mc.20343","article-title":"Melanoma susceptibility and cell cycle genes in Xiphophorus hybrids","volume":"46","author":"Butler","year":"2007","journal-title":"Mol. Carcinog."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1046\/j.1439-0388.2001.00280.x","article-title":"Inheritance of melanocytic lesions and their association with the white colour phenotype in miniature swine","volume":"118","author":"Wanke","year":"2001","journal-title":"J. Anim. Breed. Genet."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Bourneuf, E. (2017). The MeLiM Minipig: An Original Spontaneous Model to Explore Cutaneous Melanoma Genetic Basis. Front. Genet., 8.","DOI":"10.3389\/fgene.2017.00146"},{"key":"ref_5","unstructured":"Scott, D.W., and Miller, W.H.J. (2011). Melanoma. Equine Dermatology, Elsevier Saunders. [2nd ed.]."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"153","DOI":"10.2746\/042516403776114234","article-title":"Equine melanoma in a population of 296 grey Lipizzaner horses","volume":"35","author":"Seltenhammer","year":"2003","journal-title":"Equine Vet. J."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1111\/j.1939-1676.1995.tb01087.x","article-title":"Equine melanocytic tumors: A retrospective study of 53 horses (1988 to 1991)","volume":"9","author":"Valentine","year":"1995","journal-title":"J. Vet. Intern. Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1004","DOI":"10.1038\/ng.185","article-title":"A cis-acting regulatory mutation causes premature hair graying and susceptibility to melanoma in the horse","volume":"40","author":"Golovko","year":"2008","journal-title":"Nat. Genet."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Sundstrom, E., Imsland, F., Mikko, S., Wade, C., Sigurdsson, S., Pielberg, G.R., Golovko, A., Curik, I., Seltenhammer, M.H., and Solkner, J. (2012). Copy number expansion of the STX17 duplication in melanoma tissue from Grey horses. BMC Genom., 13.","DOI":"10.1186\/1471-2164-13-365"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Curik, I., Druml, T., Seltenhammer, M., Sundstrom, E., Pielberg, G.R., Andersson, L., and Solkner, J. (2013). Complex inheritance of melanoma and pigmentation of coat and skin in Grey horses. PLoS Genet., 9.","DOI":"10.1371\/journal.pgen.1003248"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1016\/j.cveq.2024.07.008","article-title":"Equine Melanoma Updates","volume":"40","author":"Hollis","year":"2024","journal-title":"Vet. Clin. N. Am. Equine Pract."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Brodesser, D.M., Kummer, S., Eichberger, J.A., Schlangen, K., Corteggio, A., Borzacchiello, G., Bertram, C.A., Brandt, S., and Pratscher, B. (2024). Deregulation of Metalloproteinase Expression in Gray Horse Melanoma Ex Vivo and In Vitro. Cells, 13.","DOI":"10.3390\/cells13110956"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Pozniak, J., and Marine, J.C. (2025). Decoding melanoma\u2019s cellular mosaic to unlock immunotherapy potential. Trends Cell Biol.","DOI":"10.1016\/j.tcb.2025.01.009"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1038\/s41580-018-0080-4","article-title":"New insights into the mechanisms of epithelial-mesenchymal transition and implications for cancer","volume":"20","author":"Dongre","year":"2019","journal-title":"Nat. Rev. Mol. Cell Biol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1016\/j.cell.2008.03.027","article-title":"The epithelial-mesenchymal transition generates cells with properties of stem cells","volume":"133","author":"Mani","year":"2008","journal-title":"Cell"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.canlet.2017.01.029","article-title":"Potential therapeutic targets of epithelial-mesenchymal transition in melanoma","volume":"391","author":"Pearlman","year":"2017","journal-title":"Cancer Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1016\/j.cell.2009.11.007","article-title":"Epithelial-mesenchymal transitions in development and disease","volume":"139","author":"Thiery","year":"2009","journal-title":"Cell"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"318","DOI":"10.1016\/j.canlet.2016.03.050","article-title":"Melanoma cell-derived exosomes promote epithelial-mesenchymal transition in primary melanocytes through paracrine\/autocrine signaling in the tumor microenvironment","volume":"376","author":"Xiao","year":"2016","journal-title":"Cancer Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1186\/s12943-016-0578-3","article-title":"Therapeutic implications of cellular and molecular biology of cancer stem cells in melanoma","volume":"16","author":"Kumar","year":"2017","journal-title":"Mol. Cancer"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1016\/j.semcancer.2019.06.019","article-title":"Cellular and molecular biology of cancer stem cells in melanoma: Possible therapeutic implications","volume":"59","author":"Marzagalli","year":"2019","journal-title":"Semin. Cancer Biol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"739","DOI":"10.1016\/S0002-9440(10)65173-5","article-title":"Vascular channel formation by human melanoma cells in vivo and in vitro: Vasculogenic mimicry","volume":"155","author":"Maniotis","year":"1999","journal-title":"Am. J. Pathol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"411","DOI":"10.1038\/nrc1092","article-title":"Vasculogenic mimicry and tumour-cell plasticity: Lessons from melanoma","volume":"3","author":"Hendrix","year":"2003","journal-title":"Nat. Rev. Cancer"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.pharmthera.2016.01.006","article-title":"Tumor cell vascular mimicry: Novel targeting opportunity in melanoma","volume":"159","author":"Hendrix","year":"2016","journal-title":"Pharmacol. Ther."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1007\/s12307-014-0156-4","article-title":"Angiotropism, pericytic mimicry and extravascular migratory metastasis in melanoma: An alternative to intravascular cancer dissemination","volume":"7","author":"Lugassy","year":"2014","journal-title":"Cancer Microenviron."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1007\/s10456-016-9500-2","article-title":"Tumor vasculogenic mimicry predicts poor prognosis in cancer patients: A meta-analysis","volume":"19","author":"Yang","year":"2016","journal-title":"Angiogenesis"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"485","DOI":"10.1016\/S0140-6736(23)00821-8","article-title":"Cutaneous melanoma","volume":"402","author":"Long","year":"2023","journal-title":"Lancet"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"674","DOI":"10.1111\/j.1600-0749.2004.00192.x","article-title":"Comparative histopathology of grey-horse-melanoma and human malignant melanoma","volume":"17","author":"Seltenhammer","year":"2004","journal-title":"Pigment Cell Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1038\/s41392-020-00259-8","article-title":"CD146, from a melanoma cell adhesion molecule to a signaling receptor","volume":"5","author":"Wang","year":"2020","journal-title":"Signal Transduct. Target. Ther."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"478","DOI":"10.1016\/j.trecan.2020.02.021","article-title":"RAC1 as a Therapeutic Target in Malignant Melanoma","volume":"6","author":"Cannon","year":"2020","journal-title":"Trends Cancer"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.freeradbiomed.2018.01.008","article-title":"Crosstalk between Rac1-mediated actin regulation and ROS production","volume":"116","author":"Acevedo","year":"2018","journal-title":"Free Radic. Biol. Med."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1089\/humc.2017.008","article-title":"Therapeutic Targeting of Protein Kinase CK2 Gene Expression in Feline Oral Squamous Cell Carcinoma: A Naturally Occurring Large-Animal Model of Head and Neck Cancer","volume":"28","author":"Cannon","year":"2017","journal-title":"Hum. Gene Ther. Clin. Dev."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1111\/pcmr.12201","article-title":"MT1-MMP modulates melanoma cell dissemination and metastasis through activation of MMP2 and RAC1","volume":"27","author":"Shaverdashvili","year":"2014","journal-title":"Pigment Cell Melanoma Res."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1111\/cup.13603","article-title":"Matrix metalloproteinases MMP-1, MMP-2, and MMP-13 are overexpressed in primary nodular melanoma","volume":"47","author":"Zamolo","year":"2020","journal-title":"J. Cutan. Pathol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2686","DOI":"10.1038\/jid.2009.130","article-title":"Stromal expression of MMP-13 is required for melanoma invasion and metastasis","volume":"129","author":"Zigrino","year":"2009","journal-title":"J. Investig. Dermatol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.ejcb.2014.01.002","article-title":"Metalloproteinases in melanoma","volume":"93","author":"Moro","year":"2014","journal-title":"Eur. J. Cell Biol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"818","DOI":"10.1016\/j.devcel.2008.05.009","article-title":"Epithelial-mesenchymal transition: At the crossroads of development and tumor metastasis","volume":"14","author":"Yang","year":"2008","journal-title":"Dev. Cell"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"251","DOI":"10.1016\/j.cell.2012.06.024","article-title":"A landscape of driver mutations in melanoma","volume":"150","author":"Hodis","year":"2012","journal-title":"Cell"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"282","DOI":"10.1111\/bjd.20427","article-title":"Melanoma pathology: New approaches and classification","volume":"185","author":"Yeh","year":"2021","journal-title":"Br. J. Dermatol."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Tschandl, P., Berghoff, A.S., Preusser, M., Burgstaller-Muehlbacher, S., Pehamberger, H., Okamoto, I., and Kittler, H. (2013). NRAS and BRAF mutations in melanoma-associated nevi and uninvolved nevi. PLoS ONE, 8.","DOI":"10.1371\/journal.pone.0069639"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"5493","DOI":"10.1242\/dev.00788","article-title":"A crucial role for Fgfr2-IIIb signalling in epidermal development and hair follicle patterning","volume":"130","author":"Petiot","year":"2003","journal-title":"Development"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"818","DOI":"10.1016\/j.celrep.2014.01.045","article-title":"Pten loss induces autocrine FGF signaling to promote skin tumorigenesis","volume":"6","author":"Mathew","year":"2014","journal-title":"Cell Rep."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1268","DOI":"10.1038\/sj.emboj.7601583","article-title":"The role of fibroblast growth factor receptor 2b in skin homeostasis and cancer development","volume":"26","author":"Grose","year":"2007","journal-title":"EMBO J."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1158\/2159-8290.CD-16-1000","article-title":"Polyclonal Secondary FGFR2 Mutations Drive Acquired Resistance to FGFR Inhibition in Patients with FGFR2 Fusion-Positive Cholangiocarcinoma","volume":"7","author":"Goyal","year":"2017","journal-title":"Cancer Discov."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1158\/1541-7786.MCR-08-0021","article-title":"Loss-of-function fibroblast growth factor receptor-2 mutations in melanoma","volume":"7","author":"Gartside","year":"2009","journal-title":"Mol. Cancer Res."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1288","DOI":"10.1158\/1541-7786.MCR-22-0871","article-title":"Competing Engagement of beta-arrestin Isoforms Balances IGF1R\/p53 Signaling and Controls Melanoma Cell Chemotherapeutic Responsiveness","volume":"21","author":"Cismas","year":"2023","journal-title":"Mol. Cancer Res."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"1358","DOI":"10.1038\/jid.2008.124","article-title":"Unraveling the mysteries of IGF-1 signaling in melanoma","volume":"128","author":"Lee","year":"2008","journal-title":"J. Investig. Dermatol."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1097\/PPO.0b013e31824d448c","article-title":"The role of the PI3K-AKT pathway in melanoma","volume":"18","author":"Davies","year":"2012","journal-title":"Cancer J."},{"key":"ref_48","unstructured":"Brodesser, D.M., Schlangen, K., Burgstaller, J., Brandt, S., and Pratscher, B. (2017, January 18\u201322). Expression signature of grey horse melanoma. Proceedings of the ESVONC, European Society of Veterinary Oncology Annual Congress, Lyon, France."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"865","DOI":"10.1126\/science.1178158","article-title":"Genome sequence, comparative analysis, and population genetics of the domestic horse","volume":"326","author":"Wade","year":"2009","journal-title":"Science"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1966","DOI":"10.1093\/bioinformatics\/btp336","article-title":"SOAP2: An improved ultrafast tool for short read alignment","volume":"25","author":"Li","year":"2009","journal-title":"Bioinformatics"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1016\/S0166-4328(01)00297-2","article-title":"Controlling the false discovery rate in behavior genetics research","volume":"125","author":"Benjamini","year":"2001","journal-title":"Behav. Brain Res."},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Fabregat, A., Sidiropoulos, K., Viteri, G., Forner, O., Marin-Garcia, P., Arnau, V., D\u2019Eustachio, P., Stein, L., and Hermjakob, H. (2017). Reactome pathway analysis: A high-performance in-memory approach. BMC Bioinform., 18.","DOI":"10.1186\/s12859-017-1559-2"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"2658","DOI":"10.3390\/v14122658","article-title":"Bovine Papillomavirus Type 1 or 2 Virion-Infected Primary Fibroblasts Constitute a Near-Natural Equine Sarcoid Model","volume":"14","author":"Hainisch","year":"2022","journal-title":"Viruses"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"1896","DOI":"10.1038\/nprot.2007.261","article-title":"Protocol for micro-purification, enrichment, pre-fractionation and storage of peptides for proteomics using StageTips","volume":"2","author":"Rappsilber","year":"2007","journal-title":"Nat. Protoc."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"2301","DOI":"10.1038\/nprot.2016.136","article-title":"The MaxQuant computational platform for mass spectrometry-based shotgun proteomics","volume":"11","author":"Tyanova","year":"2016","journal-title":"Nat. Protoc."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"731","DOI":"10.1038\/nmeth.3901","article-title":"The Perseus computational platform for comprehensive analysis of (prote)omics data","volume":"13","author":"Tyanova","year":"2016","journal-title":"Nat. Methods"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/14\/6620\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:08:01Z","timestamp":1760033281000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/14\/6620"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,7,10]]},"references-count":56,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2025,7]]}},"alternative-id":["ijms26146620"],"URL":"https:\/\/doi.org\/10.3390\/ijms26146620","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,10]]}}}