It is suggested that genes located in the 1q21 amplicon, including CKS1B, PSMD4, IL6R, ADAR, MCL1, and others, are associated with tumor proliferation and/or drug sensitivity because of upregulation of the expressed genes resulting from the increased gene dosage in MM cells with 1q21+ [37,38,39,40,41,42,43,44,45]. This evidence concerns the gene CKS1B and Miyoshi myopathy.