Thus, these cells are only marginally dependent on JAK2-V617F for survival, which may contribute to the constant development of cells persistently proliferating in the presence of JAK inhibitors after a long-term culture of various JAK2-V617F-positive AML cell lines in gradually increasing concentrations of ruxolitinib or other JAK inhibitors [9–12]. Here, JAK2 is linked to acute myeloid leukemia.