Why aren't there as many tissue spots on my section of the array as are listed on the TMA key?

The key represents the original TMA design. Tissue cores are of various lengths, hence at deeper sections, some cores have been exhausted while others remain. In addition, some tissue spots may be lost during the process of transferring the TMA section to the glass slide.

Why isn't the target tissue type present in the tissue spot?

Although TMA manufacture is guided by a histologic section that represents the surface of the donor tissue, this target tissue may not be uniformly represented in the deeper sections of the tissue. This problem is greatest with small structures (e.g. breast ducts and lobules).

Why doesn't the representative microscopic image of the target tissue in the guide sheets exactly match the tissue spot on my TMA?

The representative images have been taken from a single spot from a single QA section from a single array. Four different replicate TMA blocks were made for this series, each of which has different tissue cores. Even the same tissue core at a deeper section would not exactly match a more superficial section due to the variability inherent in tissue architecture.

Can I use antigen retrieval methods (boiling, microwave, pressure cooker, etc) on these sections?

Yes.

Can I perform in situ hybridization on these sections?

Yes.