ERBB2 and breast cancer: Overall, we have shown that sabizabulin is an effective and well-tolerated agent with activity against four HER2+ breast cancer cell lines, BT474, SKBR3, AU565 and JIMT cells, and in two HER2+ xenograft models, and that sabizabulin, but not paclitaxel, sensitizes AU565 and JIMT cells to lapatinib treatment.