BTK and Miyoshi myopathy: A study using a genome-scale small-interfering RNAs screening in MM cells revealed enhanced growth of MM cells by BTK small-interfering RNAs, supporting our findings.31 Recently, Tai et al.17 demonstrated that treatment with ibrutinib (BTK inhibitor) or shRNA-mediated transient inhibition of BTK is directly cytotoxic to MM cell lines in vitro.