JAG1 and Miyoshi myopathy: Indeed, a combination of melphalan and the GSI MRK003 showed an additive/synergic effect on retinoblastoma cell lines, whereas GSI-XII significantly improved its cytotoxicity in multiple myeloma (MM) models, and Jagged1 and 2 inhibition reverted both intrinsic and stromal cell-induced resistance of MM to melphalan [383,384,385].