Definitions

Donor block

a tissue paraffin block (see below) that contains tissue of the desired type to be placed into the tissue microarray.

Histologic section

a flat sheet of paraffin-embedded tissue cut from a paraffin block on a microtome. The thickness of the section can vary, but a typical thickness is 4 microns (micrometers).

QA

quality assurance

Recipient block

The blank paraffin block into which tissue cores are inserted to form the tissue microarray.

Tissue core

the cylindrical tissue sample removed from the donor block, which is placed in the recipient block.

TMA

tissue microarray. A recipient paraffin block into which tissue cores have been inserted in a gridded array.

Tissue paraffin block

a sample of tissue that has been fixed in formalin, processed to remove water, then infused with molten paraffin, which is allowed to harden within and around the tissue in a square mold. This is the standard method of preparing tissue for clinical histologic analysis. The paraffin block is subsequently cut on a microtome to produce thin histologic sections which are placed on glass slides. In the manufacture of TMAs, these become the donor blocks.

Tissue spot

the tissue sample present on a histologic section of a tissue microarray that corresponds to a tissue core.

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