Abstract: A method of determining a therapeutic regimen for the treatment of cancer with Dickkopf (Dkk) protein in which a mathematical model of differential equations describing the major signaling pathways involved in stem cell regulation is created and used to simulate signals from the cancer stem cell environment based upon administration of at least a single dose of Dkk in vitro and/or in vivo. A method of modulating cancer stem cells is also provided in which the stem cell computer model is simulates the effect of Dkk and performs a calibration test to determine a threshold value above which Dkk induces cell differentiation and a threshold value below which Dkk induces stem cell proliferation.