Resin Tissue Microarrays: a Universal Format for Immunohistochemistry

Abstract

S U M M A R YTissue microarray (TMA) technology allows the miniaturization and characterization of multiple tissue samples on a single slide and commonly uses formalin-fixed paraffin-embedded (FFPE) tissue or acetone-fixed frozen tissue. The former provides good morphology but can compromise antigenicity, whereas the latter provides compromised morphology with good antigenicity. Here, we report the development of TMAs in glycol methacrylate resin, which combine the advantages of both methods in one embedding format. Freshly collected tissue fixed in Ϫ 20C acetone or 10% neutral buffered formaldehyde were cored and arrayed into an intermediary medium of 2% agarose before infiltration of the agarose array with glycol methacrylate resin. Acetone-fixed resin TMA demonstrated improved morphology over acetone-fixed frozen TMA, with no loss of antigenicity. Staining for extracellular, cell surface, and nuclear antigens could be realized with monoclonal and polyclonal antibodies as well as with monomeric single-chain Fv preparations. In addition, when compared with FFPE TMA, formalin-fixed tissue in a resin TMA gave enhanced morphology and subcellular detail. Therefore, resin provides a universal format for the construction of TMAs, providing improved tissue morphology while retaining antigenicity, allows thin-section preparation, and could be used to replace preparation of frozen and FFPE TMAs for freshly collected tissue.

The Demonstration of Immunohistochemical Biomarkers in Methyl Methacrylate-Embedded Plucked Human Hair Follicles

“…This is not possible with the whole hair method (Camidge et al, 2005b) where the whole sample has to be used for each stain employed.The new methodology subsequently permits considerably greater flexibility in workload scheduling by avoiding the necessity for multiple sampling from each volunteer at each time point in the study. The great advantage of methyl methacrylate in immunohistochemistry over other commonly used resins is the ability to remove the resin by immersion in xylene (Britten et al, 1993;Howat et al, 2005), the consequence being that IHC methods developed on FFPE tissues may be transferred to MMA embedded tissues with little or no modification. This is advantageous to the investigator, saving time in method development and strengthening confidence in the assay.…”

“…The great advantage of methyl methacrylate in immunohistochemistry over other commonly used resins is the ability to remove the resin by immersion in xylene (Britten et al, 1993; Howat et al, 2005), the consequence being that IHC methods developed on FFPE tissues may be transferred to MMA embedded tissues with little or no modification. This is advantageous to the investigator, saving time in method development and strengthening confidence in the assay.…”

An Agarose Matrix Facilitates Sectioning of Tissue Microarray Blocks

“…This involves heating of the block three or four times for 1-8 hr at 35C in an oven and then cooling on a cooling plate (or in a−4C freezer) for 15 min. Howat et al (2005) reported a resin TMA in which a glycol methacrylate resin array block was cut with a rotary microtome. Agarose was used as an intermediary recipient block to produce the resin array block through a long and complicated procedure.…”

Microarrays in Diagnostics and Biomarker Development

“…In the resin tissue microarray technology (Howat et al 2005;Howat and Wilson 2010), the advantage of resin as an embedding medium that allows for very thin (down to 0.5 mm) sections with excellent tissue morphology (Britten et al 1993) has been combined with the improved antigenicity of acetone fixation for immunohistochemistry analysis. An important limitation of the resin technology is that punches cannot be cored from existing resin blocks, so that resin TMAs can only be build from nonembedded (fixed or frozen) tissues.…”