Tissue microarray service

It depends on the size of punch you select to obtain the cores. Our paraffin block size is 30 X 24 mm and 30 X 27 mm and fits the following maximum number of cores: 

30 x 24 mm

30 X 27 mm

Most studies suggest that the results from triplicate TMA cores have up to 98% concordance with the result from full sections. However, some recent studies recommend at least four cores whereas other authors achieved greater than 95% accuracy with only two cores. Beyond heterogeneity, basic technical issues mandate the use of more than one core of tissue per case. Tissue cores can be lost during sectioning and subsequent procedures, or subsequent interpretation is compromised by folding of the tissue core. Thus, by having multiple tissue cores per case, the potential impact of such loss is minimized. 

The area of interest should be identified and marked on the donor block or glass slide (or annotated on the virtual slide) using chemical resistance pen, xylene free marker or a permanent sharpie. Circle the area of interest with an appropriately sized circle, e.g., 1 mm circle for 1mm core. Use only a light touch to circle the area of interest on the block face. Please note that while marking on the block the marker tip will get clogged with paraffin. Do not press into the paraffin. It is not necessary to circle the area of every core. Just circle the area to be cored. Arrange the blocks and slides in order that they will go into the array. The array is built from left to right all the way to the end of the row (10 blocks) and then down to the left of the second row and so on. 

We recommend marking the corresponding H&E-stained slide that is the current representative of the donor block. A new H&E will be made if the block and H&E slide significantly differed. 

The TMA construction fee includes $2 fee per core harvest and transfer and the fee for empty TMA block. Other costs could be attributed to cutting and staining H&E slides of the original donor block for identification of regions to be punched in the block and final sectioning and staining of the TMA. Sectioning and staining of donor block, could be requested by filling out the “Donor block Sectioning and Staining“ form in Infinity.  

Donor blocks dimension values should not be higher than 24mm (W) x 37mm (H) x 10mm (D). If the paraffin blocks are larger, an extra charge for re-embedding will be applied. Ideally the depth of the tissue should be more than 2mm deep. Less depth will mean a lesser number of TMA slides that the constructed TMA will be able to produce.  

To make a 2mm core, the tissue area (within the donor block) should be at least 0.25 cm2. The same ratio applies to other core diameter(s). 

TMA block(s), an excel file with the donor and recipient block IDs, the TMA layout with the position of the punches within the TMA block, donor block images with the superimposed annotations as jpg file.

The exported file can be transferred to the investigator’s external hard drive.