Systemic mastocytosis is a rare, incurable disease that affects approximately one in every 10,000 people. It is a haematological tumor disease, similar to leukemia, in which the bone marrow and other organs, such as the bowel, liver or spleen, are infiltrated by mast cells. In the animal model, researchers have now discovered a new prognostic and therapeutic approach that could at least help to prevent rapid progression of the disease.