For example, one study indicates that SHP-2 may promote STAT5 activity instead of reducing it.[44] Also, other studies propose that SHP-2 may increase JAK2 activity, and promote JAK2/STAT5 signalling.[45] It is still unknown how SHP2 can both inhibit and promote JAK-STAT signalling in the JAK2/STAT5 pathway; one theory is that SHP-2 may promote activation of JAK2, but inhibit STAT5 by removing phosphate groups from it.[3]