The effect of different cancer treatment strategies on the number of differentiated cancer cells in the presence of resistance.

<p>Panels <b>a</b> and <b>b</b> display the tumor cell population after 500 days of treatment for two different types of treatment. In panel <b>a</b> we consider a treatment that can target all types of cells, and in panel <b>b</b> we consider a treatment that only targets progenitor and differentiated cells. Panels <b>c</b> and <b>d</b> display the tumor cell population after 5000 days of treatment for two different types of treatment. In panel <b>c</b> we consider a treatment that can target all types of cells, and in panel <b>d</b> we consider a treatment that only targets progenitor and differentiated cells. The pre-treatment growth parameters are identical to those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014366#pone-0014366-g002" target="_blank">Figure 2</a> and the growth rate of the resistant cells is identical to that in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014366#pone-0014366-g004" target="_blank">Figure 4</a>. In all four panels we set <i>u</i> = 5×10⁻⁹ and we set for <i>i</i> = 0,1,2. In panels <b>a</b> and <b>c</b> we set and , and vary (i.e., the drug effect on cancer stem cells) along the horizontal axis. In panels <b>b</b> and <b>d</b>, we set and , and vary (i.e., the drug effect on cancer progenitors) along the horizontal axis. In panels a and b, the vertical axis corresponds to the number of differentiated cancer cells after 500 days of treatment, including resistant and sensitive cancer cells. In panels <b>c</b> and <b>d</b>, the vertical axis corresponds to the number of differentiated cancer cells after 5000 days of treatment, including resistant and sensitive cancer cells.