Abstract: AIM: To observe the apoptosis and cell proliferation induced by adriamycin in mice with breast cancer. METHODS: Therapeutic effect of 1.25 mg·kg^-1 adriamycin (ADR)on mice MCF-7 breast cancer was observed in vivo. Apoptosis and PCNA of tumor cells were also studied by TUNEL and immune his to chemical methods. RESULTS: In the control group, the apoptotic cell index (AI)in tumor cell was 1.11 %and PCNA index (PI)was 56.38 %.In the ADR group, the rate of tumor inhibition was 43 % and the AI was 1.93 % (P <0.05).The 35.75 % of PI in ADR group was lower than that in the control group (P <0.01). CONCLUSION: Adriamycin may induce apoptosis and reduce cell proliferation.

Key words: adriamycin, breast neoplasm, apoptosis, PCNA