Comment on Nietner et al. [Virchows Arch (s2012) 461:259–269]
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KeywordsPublic Health Acetone Dehydration Xylene Molecular Approach
We have read the study of Nietner et al. [Virchows Arch (2012) 461:259–269] with interest. In general, such studies are necessary and new fixatives are needed within the growing demand for immunohistochemical and molecular approaches. The results obtained here with the HOPE technique are not surprising, since the procedure was not done according to the manufacturer's prescriptions (http://www.dcs-diagnostics.de/data/HOPE_Manual_070801.pdf). The authors did the deparaffinization with a ‘usual dehydration process’, which means an ascending series of ethanol and xylene or another intermedium. This dehydration is not compatible with the HOPE technique since first of all ethanol itself is a fixative, which influences antigenic properties, and, secondly, the HOPE I solution needs to be washed out by acetone in order to achieve a good preservation of the morphology. This explains the poor morphology and the need for pretreatment in immunohistochemistry. The right way to dehydrate HOPE-fixed materials (by acetone) is long known , which is why we cannot agree with the procedure used and the results obtained here.
With our best regards