Abstract
Microarrays are a powerful tool in modern genome analysis. The massive parallel analysis of the RNA expression level of thousands of genes accelerates the research in molecular biology and leads to new insights in signalling pathways. Furthermore, genomic gains or losses can be analyzed for complete genomes in a single experiment. This creates new opportunities for understanding distinct chromosomal changes in the development of cancer. The ability to genotype patients using single nucleotide polymorphisms is of primordial interest to the pharmaceutical industry and may result in a more individualized medicine. Tissue microarrays are very useful in the investigation of the expression of a particular gene in hundreds of specimens by in situ hybridization. Also, protein microarrays are currently being developed for studying protein-protein interactions. In conclusion, microarrays will revolutionize all aspects of molecular biology, and will probably have the same impact as the polymerase chain reaction.