Tissue Microarray

Tissue chip, also known as tissue microarray (TMA), is a new technology of molecular biology based on morphology, in which dozens to thousands of small tissue specimens are neatly arranged in regular arrays on the same carrier and made into tissue sections. It is another important biochip after GeneChip and ProteinChip, which is mainly used to study the expression of the same gene or protein in different cells or tissues, and has the advantages of high throughput, large samples, time-saving and rapid.

Tissue microarray is an integration of traditional nucleic acid in situ hybridization or immunohistochemistry test, which detects the expression of one gene in one tissue at a time, while tissue microarray detects the expression of one gene in multiple tissues at a time. Depending on the method of production, there are two types of tissue microarrays: paraffin-embedded tissue microarrays and frozen microarrays. Paraffin-embedded tissue microarrays are commonly used in oncology, in which dozens to hundreds of small cylindrical tissues (tissue core) are collected from a large number of tissue wax blocks (known as donor wax blocks, donors) by punching holes with a fine needle in a tissue microarray making machine and neatly arranged in another empty white wax block (known as recipients, recipients) to make a tissue microarray wax block. The tissue core is then sliced and transferred to a slide to make a tissue microarray.

However, paraffin-embedded tissue microarrays also have their limitations; they cannot detect changes in DNA, mRNA and protein at the same time because the optimal fixation conditions for the three are different, and frozen tissue microarrays can overcome the above shortcomings, but the procedure is complicated, and the overall effect needs to be improved. In addition, there may be some invalid tissues, displacement or detachment of tissue microarrays, false-positive or false-negative reactions and other problems.