e y ng nt Traditional chemotherapy for tumors produces strong side effects because of the lack of drug specificity and abrupt release behavior involved. Therefore, the development of suitable drug carriers for the targeted anchoring of in situ tumor cells and long-term local delivery is vital to improving the tumor cure rate. Following the emulsification-solvent-volatilization method, adriamycin (DOX)/PLGA microspheres were successfully pre-pared in this work. The size of the microspheres was concentrated at the 2.5-7.5 mu m range, thereby providing the possibility of anchoring and capturing tumor cells. The PLGA microspheres have a high encapsulation rate in relation to the chemotherapeutic drug DOX and have a good slow-release effect when applied in vivo, rendering the DOX/PLGA system applicable for targeted treatment of in situ tumors. Furthermore, the novel system was assessed for its therapeutic activity in breast cancer treatment, and the related mechanism of action was also explored.