WEE1 and neoplasm: Since the results obtained using the Δex8-targeted mice formed the basis for the formulation of the tumor suppressive role of MK5/PRAK (Sun et al., 2007) as well as for the identification of MK5/PRAK as a tumor-promoting angiogenic factor (Yoshizuka et al., 2012), these roles are challenged and should be revisited by MK5 targeting approaches deleting the entire protein kinase.