Fig. 2.

Scenarios for relationships of tumor heterogeneity and immune/tumor interactions. Heterogeneous primary tumors give rise to metastases with expression patterns that are potentially overlapping but distinct from the primary tumor. Tumor heterogeneity can induce immune cell proliferation, activation, and differentiation, along with intratumoral immune infiltration and tumor immunoediting. Cytokines and growth factors in the peripheral blood, due to secretions by immune cells in lymph node and spleen, can result in modifications of tumor growth and heterogeneity.