As levels of serum miRNAs may reflect the clinicopathologic status of cancer patients and correlate with the dysregulated pattern of the parental tumor, in this study we assessed if the levels of miR-21, miR-10b, and miR-19a in the serum of breast cancer patients were associated with aggressive characteristics of tumor cells (HER2-overexpression or amplification and IBC type), and if they had prognostic value. The gene discussed is ERBB2; the disease is breast carcinoma.