We have used proteomic methodology to identify putative biomarkers for chemo and radioresistance in human tumours.Proteomics has the advantage that results may not be confounded by alternative splicing of messenger RNA and may be translatable to commonly used immunohistochemistry techniques used in pathology laboratories.We have used two proteomic platforms 2D-gel electrophoresis with MALDI-tofrnass spectrometry and antibody microarray.Following identification of differentially expressed proteins, we have subjected these to analysis by ingenuity pathway software.Western blotting and immunohistochemistry have verified differentially expressed proteins.By comparing radioreseistant with radiosensitive breast cell lines and clinical samples, we have demonstrated that dysregulation of the proteasome may be a marker for radioresistance.With chemoresistance we have demonstrated dysregulation of tBID and 14-3-3-3 as putative biomarkers.