ERBB2 and breast cancer: On the other hand, when ERBB2 was overexpressed in breast cancer cell lines MDA-MB-231 (ERBB2-negative) and MCF 7 (ERBB2-positive) (Figure 2A) and autophagy was measured by LC3-II Western blotting, basal and amino acid starvation-induced levels of autophagy were increased by at least 40%, respectively (Figure 2B,C).