ERBB2 and breast cancer: In contrast, the combination of HLX22 and HLX02 not only enhanced HER2/HER2 homodimers internalization, but also induced HER2/EGFR heterodimers internalization both in HER2 3 + gastric cancer cell lines and in HER2 3 + breast cancer cell lines, which inhibited tumor growth promoting signals to a greater extent (Fig. 2e, h).