ERBB2 and breast cancer: Another in vitro study conducted by Chen et al. proved that autophagy is a potential novel therapeutic target for reversing lapatinib resistance of HER2-positive breast cancer cells.39 Our previous studies have demonstrated that chrysin is capable of potentiating autophagy in tumor cells by activating ER stress.21 In the present study, we uncovered that the combination treatment of pyrotinib and chrysin could yield a synergistic effect in apparently increasing autophagy within HER2-positive tumor cells by inducing ER stress.