As a result of the interaction of MM cells with stromal cells, IL-6, VEGF, and IGF-1 are secreted, and signaling pathways that cause tumor aggression, such as PI3K/AKT/mTOR, MEK/ERK, JAK/STAT3, and NF-κB, are activated [Figure 2]. Here, MTOR is linked to Miyoshi myopathy.