MYD88 and Miyoshi myopathy: We next examined signaling in early MM B cell lymphopoiesis and observed significant overexpression of CD52, MMSET, MYD88, c-Myc, CD243, Notch-1, and CD47 in B cell progenitors (Figure 2B) in all MM stages, whereas downregulated expression of CD44 was detected in active MM stages.