Morphologic and Molecular Features of Breast Ductal Carcinoma in Situ.

Ductal carcinoma in situ (DCIS) encompasses a highly heterogeneous group of lesions that differ with regard to their clinical presentations, histologic features, biomarker profiles, genetic abnormalities, and potential for progression. DCIS is a nonobligatory precursor for invasive carcinoma. With the advent of screening mammography, the incidence of DCIS has significantly increased. There is an argument that many of these lesions will not progress to invasive carcinoma within the lifetime of a patient. In addition, many studies have found enormous heterogeneity within DCIS. There is a need for biomarkers that can stratify patients with DCIS into different prognostic groups based on the biology of the disease. Estrogen and progesterone receptors are the established biomarkers that are used for clinical decision making. In addition, a number of biomarkers, such as human epidermal growth factor receptor 2 protein, p53 tumor suppressor gene, Ki-67 proliferation marker, and tumor-infiltrating lymphocytes, carry prognostic significance, although their use is considered investigational and has not been transferred to clinical practice. On the molecular level, low-grade and high-grade DCIS have different molecular alterations, and the intrinsic molecular subtypes that exist in invasive carcinoma also exist in DCIS with prognostic implications. In this article, we review the morphologic features, prognostic biomarkers, and molecular features of DCIS.