Tissue array is a composite paraffin block that contains tens and hundreds of individual tissue samples. The term "tissue macroarray" is used to designate those tissue array blocks that have 10 to 75 samples in the tissue array. Those arrays that contain greater than 100 samples are termed "tissue microarray."
Tissue arrays are created by taking a small, i.e. 0.6 to 5 mm round "punch" of representative tissue sample from routinely prepared whole section paraffin block and arranging the punched tissue cores in a grid-like fashion in a tissue array block. This technique allows high throughput analyses on paraffin-embedded tissues, for example an immunocytochemical analysis from 600 different tissues can be completed in a day.
Our laboratory can produce both tissue macro- and microarrays. Tissue macroarrays are prepared manually using custom instruments and use 2, 3, 4 and 5 mm punches and creates tissue array blocks containing 54, 30, 20 and 12 specimens per array block, respectively. For tissue microarray, we use Beecher instruments manual microarrayer, which uses 0.6 and 2 mm in diameter tissue punches and these blocks contain 150 to 500 specimens each.