In essence, ET-1-mediated expression of HIF-1α prominently affects the release of pro-angiogenic cytokines (e.g., VEGF-A, IL-8, and ET-1 itself), thereby triggering the proliferation, invasion, and extramedullary metastasis of MM cells (e.g., RPMI-8226). Here, HIF1A is linked to Miyoshi myopathy.