To construct a tissue microarray (TMA), small core biopsies (usually about 0.6mm diameter) are taken from viable, morphologically representative areas of paraffin embedded tumour tissues and assembled on a recipient paraffin block.
Making a Tissue Microarray
Production of the TMA is carried out using a specially designed instrument (Beecher Instruments, Silver Spring, Maryland) that uses two separate core needles for punching the donor and recipient blocks and a micrometre-precise coordinate system for tissue assembly on a multi-tissue block.
Paraffin Block for Tissue Microarray
Use of a 0.6mm diameter core has been validated in a number of studies, and is judged to be sufficient for assessing morphological features of the analysed tissues and allows the combination of up to 1000 cores on a single paraffin block. The position of each core taken from each block is recorded as a set of coordinates on a simple computer database. Sections of the TMA block are cut in the same way as the conventional paraffin blocks which contain material from a single patient are cut. Up to 250-300 5 micron sections can be obtained from a single TMA block. These are then mounted on a glass slide and can be used for a variety of studies, usually involving localisation of proteins using immunocytochemistry or mRNA using in situ hybridisation. In addition to the tissues of interest, control tissue material can be included in the block.
Custom made arrays will be considered. Please contact the secretariat for further details and prices.