Figure 1:

Graphical illustration of the distant and local tumor progression model. TKI sensitive, persistent, and resistant cells are shaded blue, purple, and red, respectively. The distant tumor compartment (top) is only susceptible to systemic agents, in this case chemotherapy and TKI therapy. The local tumor compartment (bottom) is additionally affected by radiation therapy. Note that TKI therapy is not only specific to sensitive cells but also leads to slowed growth of persistent cells, as depicted by the downward purple arrow in the illustration. Chemo-radiation however is assumed to have equal effects on each cell subpopulation. The initial number of distant cells is assumed to be a constant fraction of the cells in the initial primary tumor.