Figure 4

Immunologic dormancy (“equilibrium dormancy”) at niches. The immune system can control tumor cells through elimination, equilibrium, or escape. DTCs can enter dormancy during equilibrium states. Over years, environmental factors change or the genomic stability of DCTs changes, allowing dormant cells to escape (this state is called immunosurveillance) and reactivate to grow. At niches, immune cells, stroma, and endothelial cells can secret mitogens, immunosuppressive factors, and angiogenic factors that modify the tumor microenvironment and trigger cells to exit from dormancy and lead to recurrence or metastasis. CTL, cytotoxic T-lymphocytes; CXCL10, C-X-C motif chemokine 10; INFγ, Interferon gamma; MDSCs, myeloid-derived suppressor cells; NK, natural killer; TAMs, tumor-associated macrophages; T_REG, regulatory T-cells.