Abstract: OBJECTIVE: The ability of erythropoietin(EPO) to regulate tumor growth and the anticancer activity of dacarbazine(DTIC) and cisplatin(DDP) was assessed in a murine melanoma model. METHODS: C57BL/6 mice were inoculated with melanoma cell line B16 and treated with EPO alone, the designated chemotherapeutic drug (DTIC or DDP) alone, or EPO and the drug, mice treated with saline was designated as control. Tumor growth and tumor appearance were assessed daily. The day after stopping the drugs, eye balls were removed and whole blood collected in EDTA-containing tubes from some mice, the blood was used to analyze the levels of red blood cell(RBC), hematocrit(Hct), hemoglobin(Hb) and white blood cell(WBC). Subsequently, mice were sacrificed and the tumors were separated from the surrounding muscles and skin, and weighed. The remaining mice were used to study survival time. RESULTS: Tumor volume and weight of mice injected with EPO alone was not different compared to tumor-bearing animals injected with saline(P>0.05). Mice treated with EPO and DTIC was not different in tumor volume compared to those injected with DTIC alone(P>0.05). A significantly greater reduction in tumor mass was observed in EPO and cisplatin group compared to the group treated with cisplatin alone(P<0.05). Blood analysis indicated that a significant increase in RBC, Hct, and Hb was found in animals injected with EPO compared to animals that was not treated with EPO(P<0.05). CONCLUSION: EPO alone could not effect melanoma growth engrafted in mice. EPO could modulate the antitumor activity of various chemotherapeutic agents in melanoma-bearing mice, and the effect was drug related.

Key words: erythropoietin, melanoma, dacarbazine, cisplatin