Treatment of itraconazole significantly suppressed the growth of JIMT-1 cells with marked induction of apoptosis….We have demonstrated that itraconazole, which is FDA-approved drug as an anti-fungal drug, exerts anti-tumor activity in trastuzumab-resistant HER2-positive breast cancer by targeting cancer stem-like properties, suppression of the HER2 signaling as well as induction of autophagy.