ABSTRACT
With the advent of array-based technology and the sequencing of the human genome, comprehensive analysis of transcriptional variation at the genomic level has become possible. Already, the knowledge derived from gene expression profiling studies is impressive in terms of improving our understanding of the basic biology of breast cancer. Consequently, these discoveries have also challenged the currently used classification of breast cancer and the existing theories about metastatic progression. The findings of some key studies and their implications for clinical practice are discussed in this chapter.
