Eating a cancerous fish is unlikely to cause cancer in humans, especially if the fish is properly cooked, as the cancer cells would be dead and unable to multiply. Raw fish presents a different scenario, but the body typically recognizes foreign cells, including cancerous ones, as invaders and attacks them. The greater concern lies in environmental pollutants accumulated in the fish tissue, which pose a higher risk for cancer than the cancer cells themselves. When consuming raw fish, the primary health risk comes from pathogens like bacteria, rather than cancer cells. The use of wasabi with sashimi is thought to help kill bacteria, although the exact mechanism is not fully understood.