Breast cancer pathology: the impact of molecular taxonomy on morphological taxonomy.

The concept of having an 'intrinsic subtype,' or a molecular taxonomy, lets us clearly recognize that breast cancers have characteristically different patterns of gene expression, thus giving newfound significance to morphological taxonomy. In this review, the concept of the 'intrinsic subtype' is discussed, research questions are introduced to refine the significance of morphological taxonomy, and a corresponding example is presented between microarray analysis and 'immunohistochemical subtype,' or histological taxonomy.