Some authors have observed an association between HER2 positive and ER- DCIS with increased risk of recurrence, whereas in other studies these associations have not observed.23, 24, 25, 26Endocrine therapy is indicated after BCS for patients with ER+ DCIS aiming to reduce the risk of local relapse and contralateral breast recurrence.22In the sample of the present study, HT was not indicated for all patients with ER+ tumors: ∼ 40% were treated with the hormone treatment. This evidence concerns the gene ESR1 and ductal breast carcinoma in situ.