A simple and economical method for the manual construction of frozen tissue arrays

Tissue microarray has been developed to enable multiple cores of tissue in one or more new paraffin blocks. Currently, almost all tissue microarrays are made by coring cylindrical tissues from formalin-fixed and paraffin-embedded tissues. The disadvantages of formalin-fixed and paraffin-embedded tissues include the poor preservation of antigenicity of certain proteins and mRNA degradation induced by the fixation and embedding process. However, frozen tissue array construction presents technical difficulties, and tissue array devices are expensive, particularly for small- and medium-sized laboratories. We describe a simple manual method for producing well-aligned tissue arrays by a capsule freeze method that allows us to successfully perform hematoxylin-eosin and immunohistochemical stain. All 120 tissue samples were collected and constructed into blocks by this capsule freeze method. The capsules were not affected during the sectioning process, and the capsule material always disappeared during the aqueous steps of the stain processing. The frozen tissue arrays were smoothly sectioned without the use of a tape transfer system and immunohistochemical study was performed with satisfactory results. This alternative method can be applied in any laboratory, and is both simple and economical.