E2 plus FUL-stimulated growth of MCF-7/TAM2 tumors. Twenty-five ovariectomized athymic mice were implanted in the axillary mammary fat pads with 1 mm3 MCF-7/TAM2 tumor pieces, and then treated with 1.5 mg/day TAM po until the tumors were established at 0.24 cm2, then TAM was withdrawn for 1 week. Following 1 week of TAM withdrawal, the tumors reached an average cross-sectional area of 0.37 cm2 and the animals were separated into 5 treatment groups of 5 mice each (10 tumors per group) corresponding to 1.5 mg/day TAM po, 0.3 cm E2 capsule sc, 2 mg/day FUL sc, 0.3 cm E2 capsule sc plus 2 mg/day FUL sc, and Control (no treatment). The data shown represent the average tumor cross-sectional area (cm2) per group ± SE. The cross-sectional areas of MCF-7/TAM2 tumors at day 52 were compared by 1-way ANOVA. The cross-sectional areas of TAM-treated (P = 0.0026), E2-treated (P = 0.0098), and E2 plus FUL-treated MCF-7/TAM2 tumors (P = 0.018) were significantly different from control-treated tumors.