Preliminary comparison of quantity, quality, and microarray performance of RNA extracted from formalin-fixed, paraffin-embedded, and unfixed frozen tissue samples.

Microarrays have been used to simultaneously monitor the expression of thousands of genes from biological samples, an approach that can potentially uncover previously unrecognized functions of genes. Microarray analyses can rarely be conducted retrospectively because of the requirement for RNA to be obtained from fresh or unfixed frozen tissues. Archived pathology specimens would need to be used for retrospective analyses, and these are typically preserved as formalin-fixed, paraffin-embedded (FFPE) tissue.