PIK3CA and neoplasm: (1) LNT interacts with MCF-7 cells and induces cell cycle arrest at G2/M phase via MDM2/p53- and ERα-dependent pathways, leading to cell proliferation inhibition in vitro; (2) LNT suppresses activation of PI3K/Akt/MDM2/p53 and PI3K/Akt/mTOR pathways, as well as activates the ERK-dependent pathway, responsible for MCF-7 cell proliferation inhibition and apoptosis promotion in vivo (Figure 7); (3) LNT activates caspase 3-dependent signaling pathway to induce tumor cell apoptosis in vivo (Figure 7).