FOSB and Miyoshi myopathy: We previously demonstrated a key role for the AP-1 family member JUNB in MM pathogenesis, showing that MEK/ MAPK- and NFκB-dependent induction of JUNB in MM cells is essential for MM cell proliferation and survival; as well as for the protection against dexamethasone- and bortezomib-induced cell death [23]; and MM BM angiogenesis [24].