Currently, no precise morphologic or biologic prognostic factors reliably identify patients with ductal carcinoma in situ (DCIS) who ore at high risk of disease progression.DCIS is a disease with an extremely favourable prognosis and a small likelihood of dying form breast cancer, regardless of what type of treatment is received.No retrospective of prospective study to date has demonstrated a significant difference in breast cancer specific mortality regardless of treatment.The similarities between DCIS and invasive cancer suggest that an important area for future research should be elucidating the processes that can either unleash or contain the invasive potential of DCIS cells.Thus, an understanding of the biology of DCIS can assist in the prevention, the assessment, and the diagnosis of invasive breast cancer.