Scientists discover 1st known likely transmissible cancer in wild catfish

Key Points:

• Since 2013, brown bullhead catfish in Lake Memphremagog have shown unusually high rates (23%-37%) of melanoma lesions, a type of skin cancer, according to a study published in Nature.
• Researchers discovered that the melanoma tumors in these catfish are genetically similar across individuals, indicating a transmissible cancer spreading directly between fish, marking the first known case of transmissible cancer in freshwater fish.
• Unlike typical cancer, which originates from an individual's own cells, this transmissible cancer involves cancer cells moving from one fish to another, though the exact transmission mechanism remains unclear.
• Despite the lake being a drinking water source for over 175,000 people, scientists confirm there is no evidence or risk of this fish melanoma spreading to humans or other species in the area.
• This finding adds catfish to the rare list of species known to have naturally transmissible cancers and may provide new insights into cancer cell survival, immune evasion, and transmission.