Functional proteomics of breast cancer for signal pathway profiling and target discovery.

The near completion of human genome sequencing and the introduction of mass spectrometry combined with advanced bioinformatics for protein identification have led to the emergence of proteomics as a powerful tool for characterizing new markers and therapeutic targets. Breast cancer proteomics has already identified proteins of potential clinical interest, such as the molecular chaperone 14-3-3 sigma and the heat shock protein HSP90, and technological innovations such as large scale and high throughput analysis are now driving the field. Methods in functional proteomics have also been developed to study the intracellular signaling pathways that underlie the development of breast cancer cells. As illustrated by fibroblast growth factor-2 and the H19 noncoding oncogenic mRNA, proteomics is a pertinent approach to identify signaling proteins and to decipher the complex signaling circuitry involved in tumor growth and metastasis. Together with genomics, proteomics is now providing a way to define molecular processes involved in breast carcinogenesis and to identify new therapeutic targets. The next challenge will be the introduction of proteomics as a tool for the clinic, for the establishment of diagnosis, prognosis, and the monitoring of treatment; however, this ambitious goal still requires further technological progress in the field.