THBS1 and B-cell chronic lymphocytic leukemia: In CLL, the matrix glycoprotein Thrombospondin-1 (THBS1), a versatile player of the microenvironment, is capable of inducing caspase independent apoptosis of leukemic cells via CD47 ligation34–36, and increased THBS1 levels are associated with better survival of CLL patients13.