SDC1 and Miyoshi myopathy: Additionally, Wu and colleagues found a dramatic difference in gene expression between CD138- and CD138+ PCs, mainly centered on the ataxia telangiectasia mutated and Rad3 related kinase-checkpoint kinase 1 (ATR-CHK1) cell cycle pathway, which is closely related to the clonal proliferation characteristics of CD138+ PCs and correlates with low overall survival in MM patients (120).