Contagious Cancer Discovered in North American Catfish
Transmissible melanoma in catfish surprises the scientific community.
1Nature's Surprising Reality
Researchers detected transmissible melanoma in brown catfish, marking the first recorded case in fish and in freshwater ecosystems. This rare phenomenon, where cancer cells can pass from one fish to another, has caused significant ripples in the scientific world.
2Mysterious Lesions
In 2012, an abnormal increase in catfish with black lesions was noted in Lake Memphremagog, spanning Vermont and Quebec. Studies revealed these were malignant melanomas, affecting 23-37% of examined fish—an unusually high rate for the species, raising immediate scientific curiosity.
3Cracking the Genetic Puzzle
Genetic analysis yielded a startling revelation: tumor cells from different fish were more closely related to each other than to their hosts. This strongly suggested the cancer wasn't arising independently but was spreading contagiously among the catfish population.
4Transmission Mechanism Unknown
How the cancer spreads remains unclear. Hypotheses include close contact during spawning, tumor cells surviving in water/sediment, or hormonal changes weakening immunity. Notably, younger fish show no signs of the disease, hinting at age or reproduction-linked factors.
5Arsenic Connection
Elevated arsenic levels were found in tumor cells, with geographic overlap between cancer prevalence and natural arsenic-rich areas. However, researchers caution this correlation doesn't prove causation. Whether arsenic triggers or facilitates the cancer remains an open question.
6Implications for Human Cancer
This discovery opens new research avenues. Understanding how cancer cells survive and spread beyond their original host could reveal mechanisms relevant to human cancers. Scientists highlight potential clinical insights into how cancers breach biological containment in patients.
Original article: Science Latest — Kuzey Amerika'da Bulaşıcı Kanserli Yayın Balığı Keşfedildi