OBJECTIVE To investigate the effect of endostatin and doxycycline on melanoma cellular proliferation and tumor angiogenesis.METHODS The effects of endostatin and doxycycline were studied in mice transplanted with B16 melanoma cells.The mice were divided into 4 groups that were treated as follows:endostatin treatment(E group),doxycycline treatment(D group),endostatin plus doxycycline trearment(DE group),controls(C group) received no treatment.Following 9 days of treatment the tumor tissue was removed to compare the differences in the tumor necrotic rate and micro-vessel density(MVD) among the different groups.Immunohistochemical staining was conducted to detect the expression of proliferating cell nuclear antigen(PCNA)in the di?erent groups. RESULTS The MVD of the 3 experimental groups was significantly less than the control group,(F=10.888,P<0.05),indicating that doxycycline and endostatin can inhibit tumor angiogenesis by decreasing the tumor blood supply.This effect results in inhibition of tumor cellular proliferation and promotion of tumor cell necrosis.The tumor cell necrotic rate of the 3 experimental groups were all significantly higher than the C group(F=7.229,P<0.05) and the difference between the DE and C groups also was statistically significant.PCNA expression in all 3 experimental groups was statistically less than the C group(F=17.729,P<0.05). CONCLUSION The combined use of endostatin and doxycycline in vivo can influence PCNA expression and angiogenesis in melanoma,and significantly inhibit melanoma cellular proliferation. OBJECTIVE To investigate the effect of endostatin and doxycycline on melanoma cellular proliferation and tumor angiogenesis. METHODS The effects of endostatin and doxycycline were studied in mice transplanted with B16 melanoma cells. The mice were divided into 4 groups that were treated as follows: endostatin treatment ( E group, doxycycline treatment (D group), endostatin plus doxycycline trearment (DE group), controls (C group) received no treatment. Popular 9 days of treatment the tumor tissue was removed to compare the differences in the tumor necrotic rate and micro Immunogenic histochemical staining was conducted to detect the expression of proliferating cell nuclear antigen (PCNA) in the di? erent groups. RESULTS The MVD of the 3 experimental groups was significantly less than the control group, (F = 10.888, P <0.05), indicating that doxycycline and endostatin can inhibit tumor angiogenesis by decreasing the tumor blood supply. This effect results in inhibi tion of tumor cellular proliferation and promotion of tumor cell necrosis.The tumor cell necrotic rate of the 3 experimental groups were all significantly higher than the C group (F = 7.229, P <0.05) and the difference between the DE and C groups also was significant significant. PCNA expression in all 3 experimental groups was statistically less than the C group (F = 17.729, P <0.05). CONCLUSION The combined use of endostatin and doxycycline in vivo can influence PCNA expression and angiogenesis in melanoma, and significantly inhibit melanoma cellular proliferation.