Effect of phenethyl isothiocyanate (PEITC) on MCF-7 (high HER2 (HH)) cells. (A) Comparative effect of PEITC treatment in MCF-7 cells with stable overexpression of HER2 relative to the parent cells. Cells were treated for 24 h with 10 μM PEITC and whole lysate was analyzed by western blotting for phosphorylated signal transducer and activator of transcription 3 (p-STAT3) (Y705) and cleavage of poly-ADP ribose polymerase (PARP). (B) MCF-7 (HH) cells were treated with different concentrations of PEITC for 24 h, and the whole cell lysates were analyzed by western blotting. (C) MCF-7 (HH) cells treated with PEITC for 24, 48 and 72 h with increasing concentrations of PEITC and cell survival was measured by sulforhodamine B assay. The figures are representative of at least three independent experiments with eight replicates. *Statistically different compared with control (P < 0.05).