An Alternative Technology to Prepare Tissue Microarray Using Frozen Tissue Samples

Although most tissue microarray (TMA) slides are currently made from paraffin-embedded tissues, �frozen clinical tissues are also gradually being used to prepare TMAs. This is because frozen tissues contain better quality RNAs and proteins for profiling gene expressions. Here, we introduce another TMA method that is applicable to a broader range of frozen tissue samples. In this method, an agarose-gel-based array recipient block is first made using several simple instruments. Frozen donor tissues are then manually cored and arrayed into the recipient block array at −10�C. After arraying, the array block can be immediately sectioned on a cryostat microtome to make TMA slides for in situ hybridization and immunocytochemistry studies. TMAs made by this method have well-defined array configurations, good tissue/cell morphology, and well-preserved proteins and mRNAs. This low-cost and time-saving method provides an alternative tool for preparing high quality TMAs for gene expression analyses.