The recent advancement of proteomics technologies has provided us a variety of approaches for protein-expression profiling. Among these approaches, protein and antibody microarrays are promising new ones for biomarker discovery. Although at present they have several limitations with respect to sample preparation, sensitivity, specificity, and so on, protein and antibody microarrays will no doubt become a standard adjunctive method in the actual clinical scene. With this in mind, we have been establishing a novel system for antibody microarray in which surface plasmon resonance (SPR) technology is utilized for the signal detection. Up to 400 real-time antibodytarget bindings could be measured simultaneously within a single hour. Although SPR is assumed to be an expedient technology for protein and antibody microarrays, here we describe its advantages and disadvantaged compared to other detection technologies. This review focuses on the technological aspects of these two methods and a discussion of their clinical usefulness. We further emphasize the interpretation of the protein and antibody microarray results in combination with the results of DNA microarray and intracellular pathways mainly constructed from data on protein-protein interaction.
