The current study was the first to discover that silencing PRR11 down-regulated Bcl-2 expression and up-regulated Bax expression, and siPRR11 transfection with microbubble and ultrasound further enhanced such effects, suggesting that siPRR11 transfection with microbubble and ultrasound could promote the apoptosis of breast cancer cells in vitro. This evidence concerns the gene BAX and breast cancer.