The two related miRNAs miR-221 and miR-222, which have been implicated in numerous aspects of breast cancer pathology11–13 were reported to be upregulated in HER2-positive primary human breast cancer tissue11, and miR-221-HER2 co-expression was shown to be a negative prognostic marker for distant metastasis-free survival14. The gene discussed is ERBB2; the disease is breast carcinoma.