The work by Petrusca et al. highlights S1P as fundamental to send pro-tumor signals by increasing levels of the Growth Factor Independence 1 (GFI1) transcription factor, which consequently leads to increased growth and viability of MM cells, making MM cell resistant to bortezomib-induced cell death and also promoting osteoclastogenesis [112]. Here, GFI1 is linked to Miyoshi myopathy.