Tissue microarrays (TMAs) are used to analyze the expression of genes simultaneously in multiple individual tissue samples on one slide. TMAs are composed of small 0.6 - 3.0 mm cores of tissue from donor tissue paraffin blocks which are arrayed at a high density on a slide.
Technology Insight: identification of biomarkers with tissue microarray technology Jena M Giltnane and David L Rimm Nature Clinical Practice Oncology (2004) 1, 104-111
Tissue Microarrays have allowed tissue traditional analysis of conventional histologic paraffin blocks to become miniturized and high-throughput.
Histochemical and molecular detection techniques can be used on the TMA slides, and thus allow TMAs to be powerful tools to examine gene expression profiling in disease states across a variety of patients and disease conditions.
Tissue Microarray Contents
- 50 - 500 tissues or more can be analyzed per slide block
- high throughput
- relatively low cost
- can be stained with a variety of stains such as H & E stained
- slides can be analyzed with a wide-variety of techniques
- automated analysis and data collection with many techniques
Tissue Microarrays are produced using a microtome which sections tissue into 4 - 5 micrometer sections (see figure 1 above). These core tissue biopsy sections are taken from specific areas of interest from paraffin-embedded tissue blocks. These cynlindrical cores of tissue are re-embedded into an arrayed blank recipient blocks. Using this method, more than 500 tissue cores can be arrayed on a single slide! The master block was developed by Konenen et al.
- Staining of : H & E, HC, ISH,
- In situ hybridization
- Fluorescent in situ hybridization (FISH)
- In situ PCR
- RNA or DNA expression analysis
- TUNEL assay for apoptosis
- Morphological and Clinical Characterisation of Many Patient Tissues
- Experimental uniformity
- Allows amplification (and conservation) of scarce tissue samples
- Saving the assay volume
- Reduces the number of slides examined (conventional slides tissue paraffin)
- Analysis can be automated and data can be computerized
Cryo - Tissue Microarrays : Cryo-TMAs uses frozen tissues which are embedded in an optimal cutting temperature compound. These cryo-TMAs due to their freezing are superior to formalin fixed tissues for RNA and protein analysis. Also, antibodies work much betterl with frozen tissues.
Multi-tumours Tissue Microarrays : multi-tumour TMAs have many different types of tissues aligned on the slide. The technique was first used by Kononen et al., 1998. Kononen used this type of TMA to detect 6 gene amplifications. p53 expression was also examined in breast cancer tissue.
Progression Tissue Microarrays : This type of tissue microarray examines different stages of tumour (or disease) progression within a given organ. For example, examination of tumours in the breast. These slides can then be assayed for markers of interest, or biochemical analysis of the samples can be done.
Prognosis Tissue Microarrays : Disease samples such as tumour biopsies can be taken from patients and examined. These samples can be used for clinical follow-ups to monitor the patient's progression. Data is then analyzed and compared with other clinical data.
Contains the following software:
TMA-Deconvoluter and Stainfinder. The deconvoluter converts raw scoring worksheets from the 3-D Tissue Microarray layout into a 2-D tabulated table format suitable for further data analysis.
Tissue Array Data Analysis : Software to creating an interactive database for TMA image viewing and data input.
TAD : Tissue Array Database Software for Download.
TMAJ : set of software tools used to manage Tissue MicroArray (TMA) data and information..
Battifora H: The multitumor (sausage) tissue block: novel method for immunohistochemical antibody testing. Lab Invest 1986, 55:244-248.
Kononen J, Bubendorf L, Kallioniemi A, Barlund M, Schraml P, Leighton S, Torhorst J, Mihatsch MJ, Sauter G, Kallioniemi OP: Tissue microarrays for high-throughput molecular profiling of tumor specimens. Nat Med 1998, 4:844-847.