KISS1 and Miyoshi myopathy: The aim of this study was to test whether KISS1R and kisspeptin are expressed in MM cells and cells of the tumor microenvironment, whether interactions between MM cells and skeletal precursors resulted in up-regulation of the KISS1R-kisspeptin system, and whether these changes in gene expression signature could be used as a tool to develop a novel biomarker for the MM microenvironment in myeloma bone disease suitable for diagnostics and therapy.