Our results, as well as the results from other dual HER2 blockade studies, have not lent support to this hypothesis, though a recent study on T-DM1 cardiotoxicity suggests that more CEs occur with T-DM1+pertuzumab.3,16–18 In fact, T + L arm had a lower, albeit non-statistically significant, incidence of CEs. The gene discussed is ERBB2; the disease is cat-eye syndrome.