[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-344535-105":59,"doc-detail-344535-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","brown-bullhead-catfish-melanoma-represents-a-novel-transmissible-cancer","Brown bullhead catfish melanoma represents a novel transmissible cancer","","Brown bullhead catfish in Lake Memphremagog show a high melanoma incidence, prompting investigation of whether a contaminant or contagion can drive a rare clonal transmissible cancer. Whole-genome sequencing of tumour and matched non-tumour tissues found that tumour mitochondrial and nuclear genomes cluster more closely with each other than with host or unaffected fish. Hundreds of thousands of variants are shared across tumours yet absent in host fish, exceeding patterns typical of conventional cancers. The results support a fourth naturally occurring transmissible cancer type in animals, raising questions on origin, transmission mode, and long-term ecological impact.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/brown-bullhead-catfish-melanoma-represents-a-novel-transmissible-cancer/344535/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/brown-bullhead-catfish-melanoma-represents-a-novel-transmissible-cancer/344535.png","ImageObject",300,407,{"name":92,"@type":93},"Ophelia","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-09-24","2026-09-22",true,{"@type":102,"interactionType":103,"userInteractionCount":8},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What evidence suggests the melanoma may be transmissible rather than a conventional cancer?","Question",{"text":112,"@type":113},"Tumour mitochondrial and nuclear genomes are more similar to each other than to their hosts. Shared genetic variants are present in tumour samples but absent from host fish, a pattern exceeding typical conventional cancers.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How did researchers test the clonal transmissible cancer hypothesis?",{"text":117,"@type":113},"They performed whole-genome sequencing on tumour and matched non-tumour tissues, then compared mitochondrial and nuclear genome relationships and variant sharing between tumours and host fish.",{"name":119,"@type":110,"acceptedAnswer":120},"What are the ecological implications of the findings?",{"text":121,"@type":113},"The study indicates melanoma in brown bullheads represents a naturally occurring transmissible cancer type, prompting questions about transmission dynamics, origin, and long-term effects on fish populations.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},344535,1790219470,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":8,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":139,"language":140,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":67,"update_tm":144,"read_time":26},7971461741311,"https://ap-avatar.wpscdn.com/avatar/74000253aff267980c6?x-image-process=image/resize,m_fixed,w_180,h_180&k=1779345379180704826","Article  \n\n| Brown bullhead catfish melanoma represents a novel transmissible cancer |  |  |\n| --- | --- | --- |\n| [https://doi.org/10.1038/s41586-026-10828-6](https://doi.org/10.1038/s41586-026-10828-6)\u003Cbr>Received: 28 June 2025 Accepted: 19 June 2026 Published online: 22 July 2026 Open access\u003Cbr> Check for updates | Emily E. Curd1,8, Samuel F. M. Hart2,8, James Lubkowitz1,3, Kirsten M. Tracy4, Lucas Milazzo1, Matthew Bodnar5, Tom Jones5, Mark J. Henderson6,9, Peter Emerson5,9 & Julie A. Dragon1,7,9✉\u003Cbr>Since 2012, brown bullhead catfish (Ameiurusnebulosus) ina lake that spans Vermont, USA, and Quebec, Canada, have shown a high rate of melanomas, suggesting a causal contaminant or contagion1. We tested the hypothesis that this affliction represents aclonally transmissible cancer, a rare phenomenon in which cancer cells themselves spread between individuals, behaving more like parasites than conventional tumours2. Whole-genome sequencing of tumour and matched non-tumour host tissues revealed that tumour mitochondrialand nuclear genomes are more closely related to eachother than to their hosts or unaffected fish. Hundreds of thousands of genetic variants are shared among tumour samples but are absent from host fish, vastly exceeding levels seen in conventional cancers3. These findings indicate that melanoma in these brown bullheads represents the fourth documented typeof naturally occurring transmissible cancer in animals, after dogs4, Tasmanian devils5 and several bivalve species6–13. This raises important questions about the cancer’s origin, the mode of transmission and the long-term impact on fish populations. |  |\n| In 2012, anglers and biologists began observing a high proportion of |  | only three types of animals: dogs, Tasmanian devilsand several species |\n| brown bullhead (A. nebulosus, a typeof catfish) with raised black lesions |  | of bivalve2. In dogs, canine transmissible venereal tumour is a single |\n| in Lake Memphremagog, a freshwater lake in Vermont, USA, and Que- |  | lineage that arose thousands of years ago and is usually survived by the |\n| bec, Canada1 (Fig. 1). A study determined these raised black lesions tobe |  | host4,17. By contrast, Tasmanian devil facial tumour disease is only dec- |\n| malignant melanomas, on the basis of histopathological analysis, and |  | adesold, is generally lethal for the host and has arisen independently |\n| observed these lesions in 23–37% of brown bullhead sampled between |  | twice5,18,19. Bivalve transmissible neoplasia is a leukaemia-like cancer, |\n| 2014 and 2017 (ref. 1) . Melanomas have been reported from brown |  | arising and spreading independently at least ten times across at least |\n| bullheads in other bodies of water, but generally at considerably lower |  | ten bivalve species, in some cases spreading within a different host |\n| incidence1. Brown bullheads are widely distributed across Eastern North |  | species than the one in which it originated6–13. Although no transmis- |\n| America and are considered an indicator species of water quality14. |  | sible cancers have been documented in any fish species, a researcher |\n| The high incidence of cancer in Lake Memphremagog could indicate |  | in the early 1900s observed an outbreak of black tumoursin brown |\n| a local cancer-causing contagion or contaminant. One hypothesis is |  | bullheads from a Massachusetts pond20. They subsequently induced |\n| that extensive flooding in 2011 from tropical storm Irene led to reduced |  | small tumoursin naive fish through contact with tumour cells, suggest- |\n| water quality of the lake due to runoff pollution. Monitoring changes |  | ing that the cancer was caused by a contagion, but could not identify |\n| to water quality is of great concern to biologists and the public, as this |  | a transmissible agent atthe time20. Microbiome analyses conducted |\n| lake is the source of drinking water for more than 175,000 people15. |  | thus far have not revealed any viruses or other","cbCaitYHZvp4tVhF","https://ap.wps.com/l/cbCaitYHZvp4tVhF","pdf",23772018,24,"English","# Background and significance\n## Study hypothesis for transmissible cancer\n# Genomic methods and findings\n## Shared tumour variants across hosts\n# Comparisons with other transmissible cancers\n## Dogs, Tasmanian devils, and bivalves\n# Open questions\n## Origin, transmission, and population impact","[{\"question\":\"What evidence suggests the melanoma may be transmissible rather than a conventional cancer?\",\"answer\":\"Tumour mitochondrial and nuclear genomes are more similar to each other than to their hosts. Shared genetic variants are present in tumour samples but absent from host fish, a pattern exceeding typical conventional cancers.\"},{\"question\":\"How did researchers test the clonal transmissible cancer hypothesis?\",\"answer\":\"They performed whole-genome sequencing on tumour and matched non-tumour tissues, then compared mitochondrial and nuclear genome relationships and variant sharing between tumours and host fish.\"},{\"question\":\"What are the ecological implications of the findings?\",\"answer\":\"The study indicates melanoma in brown bullheads represents a naturally occurring transmissible cancer type, prompting questions about transmission dynamics, origin, and long-term effects on fish populations.\"}]","Brown bullhead catfish melanoma represents a novel transmissible cancer | PDF",1790054344]