PAK4 and mantle cell lymphoma: Some observations from the SurvExpress database were recapitulated: MM and MCL are identified among the top 20 diseases ranked according to levels of PAK1 or PAK2. Of note, PAK1 and PAK2 [but not PAK3, PAK4, PAK5 (PAK7), and PAK6] are highly expressed in CML and B‐ALL (Figs 1B,C and S2A–D).