ABSTRACT
Cancer is a highly complex disease with somatic mutations and epigenetic changes.1 Many of these molecular abnormalities, which are specific to individual neoplasms, influence the expression of genes that control the growth of a tumor, invasiveness, metastatic potential, and responsiveness or resistance to treatment. Accordingly, a major focus in clinical oncology is to develop markers for accurate diagnosis and
precise prognostic prediction based on tumor gene expression profiling.2 Such markers can be useful in the selection of appropriate therapeutic approaches for individual patients and in the design of future therapeutic trials. The final deciphering of the complete human genome, together with the improvement of high-throughput assays, has initiated the development of such markers based on a large proportion of the genes on a genome. DNA microarrays are a new and promising high-throughput assay that allow the simultaneous measurement of the level of expression for thousands of genes, or even an entire genome, from human tumor samples. For an introductive overview of biological and technical aspects of microarray assays, see Nguyen et al.3
