ERBB2 and breast cancer: The Kaplan-Meier survival curves demonstrated shorter breast cancer DFS among participants with non–luminal A subtypes (ie, luminal B, basal, and ERBB2 enriched) compared with those with the luminal A subtype, both in the overall cohort and in the HR-positive/ERBB2-negative subgroup (Figure 3; P values represent log-rank tests).