Figure 2: Anti-Tumor Activity of A Nanoparticle Formulation of GMP-grade WHI-P131 in the MMTV/Neu Transgenic Mouse Model of Chemotherapy- Resistant Breast Cancer. Tumor growth was determined by the measurement of tumors with a caliper in three dimensions three days a week and expressed as tumor volume in cubic millimeters (mm3). Tumor volumes were calculated using the formula for the volume of a prolate spheroid, V= 4/3 x 3.14 x length/2 x width/2 x depth/2. WHI-P131 [NP] was administered by daily intraperitoneal injections on 5 consecutive days per week. Tumor growth for each mouse was normalized to the starting volume for that particular tumor on day 1 of detection. Therefore, each mouse also served as its own control. The mean and standard error of mean for the normalized tumor volumes (NTV) are depicted for 38 control mice (PBS, Vehicle, 50 mg/kg WHI-P131 [NP]) with 65 target tumors, 17 WHI-P131 [NP] (100-150 mg/kg)-treated mice with 38 target tumors, 20 gefi tinib-treated mice with 28 target tumors, 34 gemcitabine-treated mice with 47 target tumors, and 28 paclitaxel-treated mice with 41 target tumors. The depicted results demonstrate a significant decrease in tumor volume and arrest of tumor growth for WHI-P131 [NP] treated mice (normalized volumes: 0.77±0.04 on day 7, P=7.5x10-9 and 0.70±0.06, P=1.5x10-7 (see Table 1) and continuation of growth for the other three drug treatments.