Because MBP-PTR1 is well behaved (i.e., it can be isolated at high concentrations in a highly pure form, remains soluble while subject to clean-up, and does not precipitate over time after freeze–thaw cycles), we next tested its ability to induce bortezomib resistance in an MM tumor xenograft model in mice. The gene discussed is MBP; the disease is Miyoshi myopathy.