According to this arresting discovery, coupled with the subtle relationship between PTEN-Akt-GSK-3β signaling and EMT and tumor metastasis, we speculated that the anti-metastasis effect of fisetin on breast cancer was mediated by PTEN-Akt-GSK-3β signaling pathway, and in which, PTEN was the most important kernel molecule. The gene discussed is GSK3B; the disease is breast cancer.