CEACAM1 and leukemia: While the exact impact of CEACAM1 expression and the expression of the other TIM-3 ligands in childhood leukemia is unknown, our group has recently shown that the three protein-based ligands are detectable on RNA level and identified high TIM-3 expression on bone marrow T cells as a prediction marker of dismal prognosis hinting to an important role of the inhibitory TIM-3 axis in ALL (19).