Consistent with this, upregulation of ABCB1, but also ABCG2, was observed in a set of paired MM samples isolated from a MM patient initially responding to CFZ-based therapy and later progressing to PCL under such therapy (baseline sample taken before initiating CFZ-based therapy, second sample obtained during consecutive disease progression of the same patient under CFZ/dexamethasone therapy (Figure 1d)). Here, ABCB1 is linked to Miyoshi myopathy.