Mollugin (1, 5, 25, 50 and 100 μM) inhibited HER2-overexpressing cancer cells with IC50 of 50 μM in a dose- and time-dependent manner. Inhibited cell proliferation and promoted apoptosis of breast and ovarian cancer cells by suppressing FAS expression through modulation of a HER2/Akt/SREBP-1c signaling pathway. Inhibited HER2 expression by suppression of NF-kB activation. The gene discussed is SREBF1; the disease is ovarian cancer.