ERBB2 and breast cancer: Thus, to unambiguously demonstrate that enhanced basal autophagy causally functioned to protect HER2-dependent human breast cancer cells from cell death upon chronic exposure to Tzb, we firstly measured autophagosome accumulation by fluorescence microscopy of endogenous LC3 (i.e. increase in punctate LC3 -a hallmark of autophagy because it is the first protein identified on the autophagosomal membrane-) and LC3-II immunoblotting (i.e. increase in the amount of the lipidation product of the autophagic conversion of LC3) [45]–[49].