Blood cancers such as leukemia are caused by genetic changes in the blood-forming stem cells of the bone marrow. Scientists at the University Medical Center Mainz have now shown how chronic inflammation can alter the bone marrow in people with age-related blood stem cell mutations at very early stages of the disease, thereby promoting its development. They found that the interaction of inflammatory tissue stem cells and certain immune cells triggers self-reinforcing inflammatory processes in the microenvironment of the bone marrow, which impair normal blood formation.