Scientists have reported significant progress in a cancer treatment experiment where injecting one tumor led to the disappearance of cancer across the body. The treatment, which may involve a new drug or therapy, has shown dramatic and rapid regression of tumors in patients, with some outlets suggesting that every patient in the trial saw their cancer vanish. However, the specific details of the treatment and its effects are still emerging, with some reports focusing on a specific type of brain cancer and others discussing the role of bacteria or reprogrammed tumor cells.