Effect of hirudin treatment on growth of MDAMB 231 cells in nude mice 4 to 8 days after subcutaneous implantation. (A) Tumors were grown for 8, 10, or 14 days prior to the initiation of hirudin treatment (20 mg/kgm) for 5 days. ▪ indicates hirudin injection; □, PBS injection (n = 4). (B) Initiation of treatment with hirudin (20 mg/kg × 5 days) 4 days after implantation of tumor when tumor nodule was neither visible nor palpable. Bars indicate SEM.