BRAF and Miyoshi myopathy: Significant degradation of key RAS-RAF-MEK-ERK pathway regulators (B-Raf, C-Raf, phospho-MEK, and phospho-ERK) was triggered by TAK-580 in a dose-dependent manner in MM cell lines, especially in U266 and INA-6, compared with dabrafenib, a representative RAF inhibitor (Figure 1A).