"Deep insight" into microarray technology

So far the classification of tumors relies on the interpretation of clinical, histopathological, immunophenotypic, cytogenetic and molecular genetic findings. Especially in hematological tumors a precise analysis of the malignant cells using classical methods such as cytomorphology and histology which both are supplemented by cytochemistry and multiparameter immunophenotyping are used in routine diagnostics for classification. Furthermore, insights into the genetic basis of the disease, i. e. disease-specific chromosomal aberrations and molecular alterations detected in the malignant cell clone, have substantially increased the importance of cytogenetics, fluorescence in situ hybridization (FISH), and polymerase chain reaction (PCR) and their combination in establishing the diagnosis in each subentity. In the clinical setting this not only implies a better understanding of the course of distinct disease subtypes but also allows the selection of disease-specific therapeutic approaches, e. g. the use of all-trans retinoic acid (ATRA) in acute promyelocytic leukemia or of imatinib in chronic myeloid leukemia. This is also true for an early application of allogeneic transplantation strategies in AML with complex aberrant karyotypes. Given this genetic background the microarray technology may become an essential tool for the optimization of the classification of tumors and thus may be used as a routine method for diagnostic purposes in the near future.