In a mouse study, rapamycin increased the risk for developing leucemia, especially in femice. Afaik the biological reasons are not clear.
One theory is that rapamycin suppresses the immune system in a way that allows leukemia cells to proliferate and grow unchecked. I hope, this won’t be a problem for us here, as we are not suppressing our immune systems.
Another theory is that rapamycin disrupts the normal function of blood stem cells, which can lead to the development of leukemia. This seems to be a risk!
Studies have shown that long-term treatment with rapamycin can increase the incidence of leukemia in mice, but the risk appears to be dose-dependent and may not be as significant at lower doses. For femice this dosage is reached earlier than in mice.