We demonstrated that GADD45B is upregulated in multiple myeloma cells by constitutive NF-κB activation, promotes malignant cell survival by suppressing proapoptotic MKK7/JNK signalling through its direct binding to and inhibition of MKK7, and is associated with poor clinical outcome in multiple myeloma patients (Tornatore et al., 2014; Tornatore et al., 2015). Here, MAPK8 is linked to AL amyloidosis.