The progress in the knowledge of molecular genetics and the availability of high-throughput technologies offer the opportunity to identify new diagnostic and prognostic markers and new therapeutic targets in human cancer. The recently developed "tissue microarraysî (TMA) technology allows parallel molecular profiling of clinical samples. Using this technique and immunohistochemistry (IHC), fluorescence in situ hybridisation (FISH), or RNA in situ hybridisation (ISH), the pathologist is now able to perform unprecedented large-scale analyses. The advantages are significant: large number of cases assessed simultaneously for numerous markers, processing in identical conditions, reduced amount of archival tissues, excellent correlation with standard methods, reduction in cost and time. This article provides a short review of this technology, and points out several aspects of the TMA construction and its applications for clinical research.