We hypothesized that the modest response to PZ in PDX line PH026, despite expressing high levels of HER2 protein, was underestimated due to the fact that the tumor at the start of the treatment was too bulky (considering the tumor to body size ratio) and did not match the most common clinical scenario where debulking surgery usually precedes standard chemotherapy treatment given to eliminate residual disease (Lee et al., 2012; Winter et al., 2008) Alternatively, the benefit of HER2‐targeted therapy might be restricted to sensitization to chemotherapy when the two are given in combination. This evidence concerns the gene ERBB2 and neoplasm.