In vivo efficacy of H2aL2a and H2aL2a conjugated DM1 in breast tumor model treatment beginning 24 hours after tumor implantation. A) 1 × 107 MDA-MB- 231 cells were injected into female SCID mice intra-mammary gland on day 0. Antibody treatment began on day 1 and animals were given i.p. injection of PBS, naked H2aL2a (30 mg/kg), or H2aL2a-DM1 (15 mg/kg). Arrows indicate injection days. n = mice per group. Tumor growth was monitored for 50 days using caliper. A shows the first 30 days of treatment, B is the full 50 day experiment. Two-way ANOVA Analysis of PBS versus H2aL2a-DM1 *P = .05, **P = .01, ****P < .001. C) Bar graphs representing the mean tumor weights ± S.E in the control and antibody treatment groups of tumors removed at day 50. * Unpaired t test was used to analyze the PBS control versus H2aL2a-DM1.