Growth of T47D:A18/neo and T47D:A18/PKCα xenograft tumors. Xenograft tumors were formed as described in materials and methods. A. T47D:A18/neo tumors (NT, 15 mice/group and E2, 3 mice/group). B. T47D:A18/PKCα tumors (10 mice/group). C. T47D:A18/PKCα tumors. Tumors were grown to an average size of 0.5 cm2. Mice were then randomized into NT, RAL or E2 groups (large arrow, 9 mice/group). Two weeks later RAL treatment was stopped (small arrow). D. T47D:A18/PKCα tumors (5 mice/group). Tumors were grown to an average size of 0.3 cm2. Mice were then randomized into NT or E2 groups (arrow).