Three flavonoids (IH, GN, and Aca) induced cell cycle arrest at G2/M phase, apoptosis, and autophagy in human breast cancer cells, in which downregulation of PI3Kγ-p110 and consequent interruption of PI3K/AKT/mTOR/p70S6K/ULK signaling pathway might be closely involved. Here, PIK3CD is linked to breast cancer.