Taken together, we speculate that the longer OS in eribulin-treated patients is associated with modulation of the tumor microenvironment, including the immune regulation system, and the baseline ALC is a potential immunological marker and a beneficial biomarker in patients with HER2-negative advanced breast cancer treated with eribulin, because eribulin exerts immunomodulatory effects via vascular remodeling. The gene discussed is ERBB2; the disease is neoplasm.