Biomarkers of chemotherapy resistance in breast cancer identified by proteomics: current status.

This review describes and discusses the advantages and limitations of proteomic approaches in the identification of biomarkers associated with chemotherapy resistance. Both gel-based (two-dimensional polyacrylamide gel electrophoresis) and gel-free (shotgun and quantitative) mass spectrometry approaches are discussed. Non-mass spectrometry approaches including antibody microarray platforms are described as complementary proteomic strategies. Methods for technical confirmation and clinical validation of putative biomarkers are presented. Use of this proteomic toolbox in the quest for biomarkers of chemotherapy resistance in breast cancer is reviewed. Technical aspects of sample selection, acquisition, storage and analysis are discussed and putative biomarkers identified through proteomic approaches are presented.