ERBB2 and amenorrhea: The rates of treatment-induced amenorrhea were similar in the four anti-HER2 treatment arms, being 72.6% with trastuzumab alone, 74.0% with lapatinib alone, 72.1% with trastuzumab followed by lapatinib and 74.8% with dual anti-HER2 blockade of trastuzumab plus lapatinib (Figure 1) [4].