Evaluating the Risk of Upstaging HER2-Positive DCIS to Invasive Breast Cancer.

Background: Overexpression of human epidermal growth factor 2 (HER2) in invasive breast cancer (IBC) is an independent poor prognostic factor. However, the significance of HER2 overexpression in ductal carcinoma in situ (DCIS) is not well defined. The current study assessed the correlation of HER2 DCIS with the rate of upstaging to IBC on the final pathology.