ITGB2 and plasma cell myeloma: In a macrophage–myeloma contact model, plasma‐membrane protein/gene profiling assays have demonstrated that CD18 and selectins in macrophages remarkably contribute to chemoresistance via combining with intracellular cell adhesion molecule‐1 (ICAM‐1) and P‐selectin glycoprotein ligand‐1 (PSGL‐1), respectively, in myeloma cells.