ITGA4 and Miyoshi myopathy: The in vivo phenotypic studies of Itga4 (α4) KO 5TGM1-GFP and WT 5TGM1-GFP, indicates that VLA4 on MM cells participates in BM homing, extramedullary manifestation, BM tumor burden, and survival, emphasizing the importance of MM-BM microenvironment interaction contributed by VLA4.