In the post-genomic era, proteomic strategies are at the forefront of cancer research. By studying the complement of all expressed genes, proteomics aims to provide knowledge of biomarkers indicative of the physiological state of cancer cells at a specific time, enabling screening, early diagnosis, monitoring the course of cancer development/progression, and gauging the efficacy and safety of novel therapeutic agents. Onco-proteomics thus has the ability to revolutionize oncology practice by delivering highly selective and individualised clinical care. One of the proteomic techniques, two-dimensional (2D) difference in gel electrophoresis (DIGE) enables simultaneous examination and comparison of multiple samples using cyanine dyes to label amino acid residues that are then separated based on charge and mass. This technique reduces variability, improves reproducibility, and allows easier quantitation when compared with traditional 2D polyacrylamide gel electrophoresis (PAGE). These advantages combined with universal availability makes 2D-DIGE a first method of choice in cancer proteome analysis of diverse specimens, including tissues, cell lines, blood, and other body fluids.