Figure 3: Panel A. Differentiating agent which acts on the progenitor cells, transit amplifying cells and the differentiated cells dramatically decreases the tumor cell population but does not lead to the elimination of cancer cells. Panel B. A dual regimen consisting of a combination of a stem cell antagonist and a differentiating agent which acts on the progenitor cells, transit amplifying cells and the pre-differentiated cells causes a rapid depletion of the cell population in all layers and complete resolution of the tumor.