Interestingly, recent studies suggest that higher HRG mRNA expression, and low HER2 levels predict a clinical benefit from the addition of seribantumab (MM-121) to standard of care therapies in patients with platinum-resistant/refractory ovarian cancer, hormone receptor-positive HER2-low breast cancer and EGFR wild-type NSCLC [91, 92]. This evidence concerns the gene ERBB2 and breast cancer.