If cells in other groups were considered ER81 positive with IRS ≥ 3, ER81 overexpression was detected in 25.7% (9/35) of HUT, 41.2% (7/17) of ADH, 54.5% (12/22) of pure DCIS, and 63.0% (51/81) of IDC. This evidence concerns the gene ETV1 and ductal breast carcinoma in situ.