Microarray-based gene expression profiling of hematologic malignancies: basic concepts and clinical applications.

Each cell in our body contains a set of tens of thousands of genes, out of which a set of several thousands determines the cell's characteristics. The deciphering of the sequence of the human genome combined with the technical feasibility to simultaneously measure the gene expression levels of thousands of genes had revolutionized our understanding of cellular processes. This ability has great significance in our comprehension of the mechanisms that bring about diseases in general and hematologic malignancies in particular. Several new high-throughput technologies, commonly referred as microarrays, enable us to perform such measurements and concurrently, bioinformatic and statistical tools were developed to analyze the data obtained by using microarrays. In this review we present examples of analyses of hematologic malignancies using microarrays which contribute to refinement of diagnosis, identification of novel disease subtypes and of relationships between diseases that were previously considered to be unrelated, prediction of response to treatment and identification of genes and pathways linked to pathogenesis, thus defining targets to rational therapy.