In a study with shorter follow‐up (20 months vs. 10 years) of 843 patients with HER2‐positive breast cancer, NLR was not prognostic without trastuzumab but was associated with better DFS when baseline NLR was low (cut‐off = 1.830) in those receiving one year of adjuvant trastuzumab. This evidence concerns the gene ERBB2 and breast cancer.