[Pathology--on a molecular level (determination of nucleic acids from fixed embedded samples)]

Molecular biological techniques may open new avenues to pathological archives. Fixed and paraffin embedded blocks are a suitable source of nucleic acids, especially of DNA, for retrospective analysis. The quality of DNA depends mainly on the fixation procedure. High molecular weight DNA allows Southern hybridization, but fragmented DNA also became a target with the appearance of polymerase chain reaction (PCR). PCR has rising applicability and enables amplification of required sequence even from one section. Using these techniques on archieved materials a wide variety of informations, e.g. correlation between morphology, phenotypic expression and gene alteration, will be available.