ERBB2 and breast cancer: HER2-low expression was associated with a significant benefit in RFS among all patients (HR, 0.90; 95% CI, 0.85-0.95), patients with hormone receptor-positive BC (HR, 0.90; 95% CI, 0.84-0.96), but no significant difference in RFS was found in patients with TNBC (HR, 0.80; 95% CI, 0.55-1.16).<h4>Conclusions</h4>Among patients with early-stage BC, patients with HER2-low expression BC had better OS in the overall population, hormone receptor-positive and TNBC subgroups.