WWTR1 and cancer: Members of the MARK subfamily, including MARK2, 3 and 4, regulate the Hippo kinase cassette in diverse models including Drosophila, mice and human cancer cell lines by phosphorylating MST1/2, SAV [29,51,52,53,54,55] and, as found in a recent study, NF2 and YAP/TAZ [53].