# Contagious Cancer Spreading in a Lake This type of cancer, first seen in fish, could it spread to humans? - **Source:** [NYT > Science](https://brifing.si/source/794f9fbd-c10f-44d6-932d-9039af67922c) - **Published:** 2026-07-22 - **Topic:** [Business](https://brifing.si/c/business) - **Original article:** - **On Brifing:** https://brifing.si/s/575b9076-2ce3-4bcd-93fc-21016d47fff5 ## What is Contagious Cancer? Contagious cancer is a rare phenomenon where tumor cells spread directly from one organism to another. Until now, it had only been detected in a few animal species. This case serves as a striking example of how cancer can spread like an infectious disease. ## First Time in Fish Researchers have identified contagious cancer in a fish population living in a lake for the first time. This discovery shows that cancer can spread directly among fish through contact. The findings are considered a significant step in understanding the evolutionary processes of cancer. ## How Does It Spread? Cancer cells are transmitted between fish through skin lesions. Tumor cells floating freely in the water can infect healthy fish. This mechanism raises new questions about how cancer spreads and has surprised researchers. ## Is There a Risk for Humans? Currently, the risk of transmission to humans appears low. However, this discovery strengthens the idea that cancer can be contagious. Scientists warn that similar mechanisms, though rare, could occur in humans and emphasize the need for caution. ## Public Health Implications These findings offer important insights for public health. The fact that cancer can be contagious highlights the need to protect water sources and monitor fish populations. Such studies could play a critical role in reducing future epidemic risks. ## Echoes in the Scientific Community The discovery has caused a major stir in the scientific community. This finding, which adds a new dimension to cancer research, paves the way for new studies in medicine and biology. Researchers stress that more studies are needed to understand the details of this phenomenon. ## Sources covering this story - https://www.nytimes.com/2026/07/22/science/contagious-cancer-catfish.html — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._