This suggests that blood cancer treatment with chemical inhibitors targeting CHK1 may cause collateral damage within the healthy hematopoietic system, at least in cycling lymphoid or erythroid progenitors, yet the role of Chk1 in early hematopoiesis and stem cell dynamics as well as for adult blood cell homeostasis remains unexplored. This evidence concerns the gene CHEK1 and hematopoietic and lymphoid system neoplasm.