Methodological Approach to Tissue Microarray for Studying the Normal and Cancerous Human Breast

Tissue microarray (TMA) technology is a tool that allows for the rapid evaluation of a large number of tissue samples on a single section of a microscope slide [1]. Cores of paraffin embedded tissue are removed from the original donor block and re-embedded into a recipient block in an ordered pattern of hundreds of cores. The cores can be from a variety of normal and abnormal types of tissue or stages of tumor and can be used to survey marker expression. This is more expedient than staining and scoring full sections from each donor block; it conserves the reagents used in the assay (e.g., immunohistochemistry or fluorescent in situ hybridization) [1–9], and extends the use of the original donor blocks. Many techniques for preparing the TMAs are in use with variable performance characteristics depending upon the tissue type, the coring procedure, and instrumentation (Fig. 4.1). The advantage of TMA is that it allows for examination of markers with clinical features, associations to be made between different markers and of markers with response to therapy or prognosis, and assessment of markers for the purpose of guiding treatment.