Tissue Microarrays: Overview

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Tissue MicroarraysOverview

• Small cylindrical tissue samples (cores) are
  taken from donor formalin-fixed paraffin-embedded
  tissue blocks and placed into a recipient
  paraffin block in a gridded array.Resulting
  histologic sections can contain up to many
  hundred tissue samples (tissue spots)

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Beecher InstrumentsManual Tissue Microarray
Apparatus
Needle holder slides up down to collect
deposit tissue cores
Calipers move the needle holder in precise
increments in the x y directions to form the
TMA grid
Hollow needles punch holes in donor
recipient blocks
Holds recipient block steady during TMA
manufacture
Stage to support donor block during tissue
sampling
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Review of TMA manufacture
A hole is made into the recipient block at a
predetermined position
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Review of TMA manufacture
The stage is placed over the recipient block. A
donor block is placed on the stage. The guide
slide is positioned on the block to best match
the contours of the tissue. Note that the guide
slide has been circled to indicate the position
of the target tissue.
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Review of TMA manufacture
With the guide slide placed in the best
approximation with the tissue in the block, the
donor block is moved such that the circled area
of target tissue is immediately under the needle
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Review of TMA manufacture
Note that the maker of the TMA is guided solely
by the gross visual examination of tissue
contours and the circled area. No microscopic
assessments are made during this phase of TMA
manufacture.
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Review of TMA manufacture
The slide is removed, and the needle is driven
into the donor block.
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Review of TMA manufacture
The needle, containing the tissue sample, is
withdrawn from the donor block, and the stage and
the donor block are removed. The
tissue-containing needle is lowered over the
previously-made hole in the recipient block.
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Review of TMA manufacture
The tissue core is inserted into the recipient
block by pressing on the stylus.
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Tissue core in recipient block
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The tissue cores sizes, their spacing, and their
arrangement in the block are at the discretion of
the designer of the TMA.
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Increasing magnification of a TMA
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