COP1 and plasma cell myeloma: The data of gene expression profiling from 3 independent MM cohorts (TT3, HOVON65 and APEX) were analyzed, which indicated that high RFWD2-expression patients were intimately associated with adverse prognosis, disease relapse and myeloma cell proliferation, as consistent with our previous results in TT2 and GMMG-HD4 cohort (Gu et al., 2020).