BTK is not exclusively expressed in MM cells, and the MM BM microenvironment contains numerous hematopoietic cell types; therefore, we examined the consequences of BTK silencing in MM cells on their growth in vitro and in vivo and on their ability to metastasize to bone in our SCID-rab model for MM.20 The study was conducted with the interleukin-6 (IL-6)-dependent INA6 MM cell line. The gene discussed is BTK; the disease is Miyoshi myopathy.