[The role of molecular genetics in dermatologic diagnosis].

Modern molecular techniques have tremendously expanded our knowledge about the biologic processes in healthy individuals as well as our understanding about the pathologic events in an increasing number of dermatological diseases. These technologies initially came from basic molecular biology and genetic research but have become firmly anchored in clinical diagnosis approaches. Included in this group are immunohistochemistry (IHC), polymerase chain reaction (PCR), fluorescence in situ hybridization (FISH), chromogen in situ hybridization (CISH), comparative genomic hybridization (CGH), and microarray technology. IHC and PCR already belong to the armamentarium for routine daily diagnostics due to their high degree of standardization and reproducibility, ease of use and relatively low costs. Others like FISH and CISH are currently employed for specific indications in a growing number of larger laboratories, whereas CGH and microarray technology still remain in the hands of a few highly specialized laboratories. These new ancillary methods will help to improve diagnostic accuracy particularly in cases in which conventional histopathology is ambiguous. In addition, they will provide new and important information concerning the prognosis, progression and response rate to therapies in several particular malignant diseases.