MAPK3 and plasma cell myeloma: Our results show that myeloma cell integrin α6 binds to laminin 8 and epidermal growth factor receptor (EGFR) on MSCs, forms a trimer complex, activates the ERK1/2, STAT1/3, PI3K/Akt signaling pathways, enhances the secretion of osteolytic cytokines from myeloma cells and MSCs.