Exploring the dynamical phases of tumor-immune interaction

In the growth of malignant tumor, cancer cells are able to escape from the surveillance of immune cells. Various factors are proposed to explain the immune evasion, such as mechanical barrier to immune cells, insufficiency of nutrient, adverse biochemical environment for immune response. More surprisingly, some immune cells seem to have a pro-tumor role, e.g. by secreting certain growth factor molecules. The tumor-immune microenvironment therefore becomes a complicated ecological system. We built a simplified dynamical system modeling these interactions, and try to map distinct dynamical states to biological observations. We also try to provide a perspective on some evident differences between tumor-immune microenvironment and macroscopic natural predator-prey systems, such as the absence of oscillatory phase in the former.