Klauber-DeMore's group had previously discovered that a protein called SFRP2 stimulates blood vessel growth and is expressed in human breast cancers. While investigating the mechanism through which SFRP2 stimulates blood vessel growth, they found that SFRP2 activates calcineurin in blood vessel cells. Based on this mechanism, Klauber-DeMore thought that Tacrolimus might also bind to and inactivate calcineurin in blood vessel cells, thereby blocking new blood vessel growth to tumors. The team tested this theory in a pre-clinical breast tumor model and found that orally administered Tacrolimus inhibited breast tumor growth rate by over 70 percent.

Klauber-DeMore said, "This data is encouraging, but we don't know yet whether Tacrolimus will inhibit breast cancer growth in humans. However, this pre-clinical study provides a reasoning for the next step, which will be to perform a clinical trial using Tacrolimus in patients with breast cancer."

Source: University of North Carolina School of Medicine