Appraisal of progenitor markers in the context of molecular classification of breast cancers

Clinical management of breast cancer relies on case stratification, which increasingly employs molecular markers. The motivation behind delineating breast epithelial differentiation is to better target cancer cases through innate sensitivities bequeathed to the cancer from its normal progenitor state. A combination of histopathological and molecular classification of breast cancer cases suggests a role for progenitors in particular breast cancer cases. Although a remarkable fraction of the real tissue repertoire is maintained within a population of independent cell line cultures, some steps that are closer to the terminal differentiation state and that form a majority of primary human breast tissues are missing in the cell line cultures. This raises concerns about current breast cancer models.