Utility of two DNA extraction methods using formalin-fixed paraffin-embedded tissues in identifying congenital cytomegalovirus infection by polymerase chain reaction.

ABSTRACT

Formalin-fixed paraffin-embedded (FFPE) tissues are a source of biological material for molecular studies; several methods to extract DNA from FFPE tissues have been reported. This process is challenging because of formaldehyde-induced cross-linking between proteins and DNA as well as molecule fragmentation when unbuffered formalin is used for fixation. Here, 2 methods for DNA extraction from FFPE tissues, based on a chelating resin and silica membrane columns, were modified and compared in their capacity to detect human cytomegalovirus (HCMV) in congenital infections. Both methods were tested on 121 samples of brain, lung, spleen, and liver derived from 36 deceased preterm newborns. Twelve patients were selected, and UL55 and UL75 HCMV genes were detected by polymerase chain reaction in 16/36 samples. These 2 methods represent a useful tool for DNA recovery from FFPE tissues and HCMV molecular identification with the advantage of low cost, minimal steps, minimal sample use, being solvent-free, and being easy to implement in the laboratory.