SSR4, as well as other ER-targeted proteins, such as CD320, NAPSA, and FTL, were selected for further validation analysis based on the fact that ER stress is considered to be one of the most important processes in maintaining and targeting MM cells and augmentation of ER overload by proteasome inhibitors has emerged as an important therapeutic strategy for MM treatment. This evidence concerns the gene FTL and Miyoshi myopathy.