PTEN and breast cancer: Our study showed that LY294002, as the PI3K inhibitor which served as a positive control for this experiment, could reduce p-PI3K/p85α and p-PI3K/p110α, increase the expression of PTEN, and block the PI3K/AKT pathway to inhibit the triple-negative breast cancer MDA-MB-231 cell proliferation, which suggested that the inhibitor of PI3K/AKT pathway played an important role in the development of breast cancer.