WNK proteins are serine/threonine kinases that undergo autophosphorylation and require phosphorylation of at least one serine residue within the WNK activation loop to become active. The four WNK proteins (WNK1, WNK2, WNK3 and WNK4) share high homology within their kinase domains and the adjacent auto-inhibitory domain. Although most research has focussed on the role of WNK1, WNK3 and WNK4 in regulating different ion transporters in both the kidney and extrarenal tissues, there is growing evidence for additional roles of WNK kinases in various signalling cascades related to cancer. Moreover, there may be a role of WNK proteins in G1/S cell cycle progression, metabolic tumour cell adaptation, evasion of apoptosis and metastasis[1].