Because this person has AIDS autoimmune system has collapsed, unable to use immune cells to attack foreign substances, once the parasite has cancer, then the cancer cell is facing no natural predator growth environment, about the Asian carp in the United States. Cancer cells that are not recognized by the immune system grow freely, invade various tissues, and travel throughout the body as blood and lymph circulate. And then this guy's gone. So it's not that cancer cells are contagious. I think it's a situation where the autoimmune system can't recognize it, and the allogeneic body is treated as a situation in which autologous cells proliferate. Even if there were cancer parasites in the body, it would not have survived if the autoimmune system had not been severely damaged. This kind of case is indeed rare in a hundred years, the pathological tissue sections in the paper can indeed see that the cells in the lymph nodes similar to the germ area are much smaller than the normal cells, and there is a mass-like aggregation structure. Such careful observation and bold reasoning is not possible without decades of experience, very interesting cases.