{"id":1208,"date":"2026-07-27T14:53:24","date_gmt":"2026-07-27T14:53:24","guid":{"rendered":"https:\/\/redzine.co.uk\/index.php\/2026\/07\/27\/some-animals-catch-cancer-from-others-in-their-species-heres-why-humans-arent-one-of-them\/"},"modified":"2026-07-27T14:53:24","modified_gmt":"2026-07-27T14:53:24","slug":"some-animals-catch-cancer-from-others-in-their-species-heres-why-humans-arent-one-of-them","status":"publish","type":"post","link":"https:\/\/redzine.co.uk\/index.php\/2026\/07\/27\/some-animals-catch-cancer-from-others-in-their-species-heres-why-humans-arent-one-of-them\/","title":{"rendered":"Some animals catch cancer from others in their species \u2013 here\u2019s why humans aren\u2019t one of them"},"content":{"rendered":"
Bullhead catfish.<\/span> jack perks\/Shutterstock.com<\/a><\/span><\/figcaption><\/figure>\n

Scientists in Vermont have just discovered<\/a> something that shouldn\u2019t really be possible: a skin cancer that\u2019s spreading from catfish to catfish. It\u2019s only the fourth transmissible cancer ever found in nature.<\/p>\n

Catfish now join Tasmanian devils<\/a>, dogs<\/a> and shellfish<\/a> as the only animals known to carry naturally occurring cancers that can pass between individuals. In each case, cancer cells break free from one body, travel to another and carry on living and dividing as cancer cells in their new host. No virus, bacteria or parasite is involved \u2013 it\u2019s the cancer cells themselves doing the spreading, which is what makes them so unusual.<\/p>\n

Tasmanian devils bite each other\u2019s faces when mating or fighting, letting tumour cells pass directly from one animal\u2019s wounds into another\u2019s. Something similar happens in dogs, where canine transmissible venereal tumour cells spread between mating partners via damage to their genitals.<\/p>\n

Shellfish do it differently again, passing cancer cells to one another through the water they live in. When a shellfish with cancer dies, it releases huge numbers of cancerous blood cells into the water. Other shellfish filter that water as they feed, and can pick up the cancer cells in the process.<\/p>\n

Exactly how the disease is spreading between catfish is still being worked out. The scientists behind the study<\/a> have suggested it could be linked to mating behaviour, as in dogs and Tasmanian devils, or to catfish picking up cancer cells from the water, as happens in shellfish.<\/p>\n

Why is this so rare?<\/h2>\n

Transmissible cancers need living cancer cells to move from one body to another and then take hold in their new host \u2013 which sounds simple, but is biologically extremely tricky.<\/p>\n

A healthy immune system is a formidable defence, constantly hunting down and destroying anything that isn\u2019t \u201cself\u201d. Cancer cells from another animal look foreign to the immune system, even if they come from the same species, so they\u2019re usually wiped out fast. It\u2019s the same principle behind organ transplants: a donated organ can be rejected by the recipient\u2019s immune system, which is why transplant patients are given immune-suppressing drugs.<\/p>\n

Genetics adds another layer of difficulty. Most animals \u2013 humans included \u2013 have huge genetic variation even within their own species, so cancer cells from one individual are usually too different to survive in another body of the same species. Tasmanian devils are a rare exception: their genetic diversity is unusually low<\/a>, which is part of why their facial tumour disease spreads so easily.<\/p>\n

Then there\u2019s the sheer fragility of cells. Picture a soap bubble balanced on a pin \u2013 the smallest knock, change in temperature or brush with air or sunlight, and it\u2019s gone. Cells are much the same. Even when cancer cells do escape a body, they usually die before they reach a new one. That\u2019s why transmissible cancers tend to need a direct route between hosts: injection of cells in Tasmanian devils, close contact between membranes in dogs, or a survivable medium like seawater in shellfish.<\/p>\n

The good news is that there\u2019s no evidence of a naturally occurring, independently spreading cancer in humans. A true transmissible cancer is one where cancer cells break away from their original host, become an independent lineage, spread between people, and then persist and evolve as a self-sustaining clone in their own right. <\/p>\n

There are rare cases in humans that can look similar but aren\u2019t \u2013 such as cancer cells present in a transplanted organ<\/a>, cancer passed from mother to baby<\/a> before birth, a lab worker accidentally infected by a needle, or cancers caused by viruses such as human papillomavirus (HPV)<\/a>. These are one-off transfers, not a cancer with an independent life of its own.<\/p>\n

Studying transmissible cancers in other animals still has plenty to teach us about human cancer, though, including how tumours evolve, dodge the immune system and spread. It\u2019s a window into cancer biology that human tumours alone can\u2019t offer.<\/p>\n

\"The<\/p>\n

Dr Lewis C. E. Mason works for Kingston University London as a Lecturer in Biological Sciences (Microbiology). He has previously received funding from the National Institute for Health and Care Research (NIHR). He is a member of the Royal Society of Biology (RSB), Institute of Biomedical Science (IBMS), Microbiology Society, Applied Microbiology International, AdvanceHE, British Society for Antimicrobial Chemotherapy (BSAC), British Association for Sexual Health and HIV (BASHH), and TARGetAMR.<\/span><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Bullhead catfish. jack perks\/Shutterstock.com Scientists in Vermont have just discovered something that shouldn\u2019t really be possible: a skin cancer that\u2019s spreading from catfish to catfish. It\u2019s only the fourth transmissible cancer ever found in nature. Catfish now join Tasmanian devils, dogs and shellfish as the only animals known to carry naturally occurring cancers that can […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1208","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/1208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/comments?post=1208"}],"version-history":[{"count":0,"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/1208\/revisions"}],"wp:attachment":[{"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/media?parent=1208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/categories?post=1208"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/redzine.co.uk\/index.php\/wp-json\/wp\/v2\/tags?post=1208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}