Invadosome-targeting peptides reduce THP-1 xenograft growth and host cell infiltration. In THP-1–derived xenograft differences were statistically significant at P < .001 and P = .004 for HFDDDE- (A) or DDGW-treated groups (B), respectively, compared with vehicle-treated group. (C) Staining of tumor-infiltrating leukocytes with an α_Mβ₂ integrin antibody (top panel) and tumor vasculature with an anti-CD31 monoclonal antibody (bottom panel). Representative tissue sections are shown from mice treated with saline, HFDDDE, or DDGW. Scale bar, 200 μm.