ERBB2 and breast cancer: In particular, MCF-7 (HR-positive, HER2-negative), BT474 (HR-positive, HER2-positive), KPL-4 (HR-negative, HER2-positive), and SUM159 (triple-negative) BC cell lines with PIK3CA mutation were treated for 3 days with taselisib or ipatasertib and VRL, eribulin, and paclitaxel in concentrations of IC50.