Figure 1. Potential immunoediting in multiple myeloma.

Cancer immunoediting involves three sequential phases: elimination, equilibrium, and escape (15). Elimination is mediated by collaboration of the adaptive and the innate immunity to eradicate malignant cells prior to the onset of clinical presentation. However, if elimination is incomplete and rare myeloma cell variants enter dormancy, equilibrium is established. After autologous stem cell transplantation (ASCT), equilibrium is mediated by effector T cells and is IFN-γ–dependent. Escape is associated with the accumulation of genetic mutations, resistance to immune effectors, CD8⁺ T cell exhaustion, and changes in the microenvironment. Regulatory T cells (Tregs), suppressive dendritic cells (DCs), T helper 17 (Th17) cells, tumor-associated macrophages, and myeloid-derived suppressor cells (MDSCs) all encourage escape and inhibit CD8⁺ T cell function. ASCT appears to restore a period of immune equilibrium but is usually followed by further escape and disease progression.