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TISSUE MICROARRAY PRESENTATION.pptx
- 1.
- 2. Tissue microarray(TMA) is a method used to evaluate numerous samples of tissue in a short time. First introduced { Battifora (1986) } Multiple tissue samples arranged in a single paraffin block
- 3. Microarray containsmany small representative tissue samples from hundreds of different cases assembled on a single histologic slide Allows high throughput analysis of multiple specimens at same time
- 4. In thetissue microarray technique, a hollow needle is used to remove tissue cores as small as 0.6 mm in diameter from regions of interest in paraffin-embedded tissues such as clinical biopsies or tumor samples. These tissue cores are then inserted in a recipient paraffin block in a precisely spaced, array pattern.
- 6. Tissue microarraysare paraffin blocks produced by extracting cylindrical tissue cores from different paraffin donor blocks and re-embedding these into a single recipient (microarray) block at defined array coordinates.
- 10. Experimental applications Clinical applications
- 11. Array comparativegenomic hybridization (aCGH) Genotyping Sequencing Genome tiling Gene expression
- 12. Gene expressionprofiling as an ancillary diagnostic tool for the pathologist Predicting disease behavior Predicting survival Predicting therapeutic response Nontumor pathology
- 13. Genotyping Genomecopy number Methylation DNA sequencing
- 14. Amplification ofa scarce resource Simultaneous analysis of very large numbers of specimens Experimental uniformity Decreased assay volume, time and cost effective Does not destroy original block for diagnosis and conserves valuable tissue
- 16. Used asquality control in H&E and IHC Used for wide range of staining procedures, IHC, ISH, FISH, Special stains and H&E Enable study and evaluation of many diseases(diagnostic tool) In Clinical pathology as quality control for new antibodies
- 17. Tissue heterogenity One of the most common criticisms of tissue microarray is that the small cores sampled may not be representative of the whole tumor, particularly in heterogenous cancers such as prostate adenocarcinoma and Hodgkin lymphoma
- 18. Determine whichblocks will be arrayed Mark the area of interest either on the slide or block Both should be marked in same area At least 1mm thick If marked area< 1mm thick , two cores are stacked on top of each other
- 19.
- 20. Four sizes: 0.6 , 1.0 , 1.5 , and 2.0mm General use Ideal spacing-----------0.1mm
- 21. Blank paraffinwax block There should be no holes in the block caused by air bubbles 1.0mm needle preferred: gives a desireable core and leaves little distortion in donor block Ensure the alignment of punches
- 27. Smoothing andSectioning Microtomy Troubleshooting and tips: Core doesn’t come out easily, punch tip is bent, change it Tissue core pushed too deep
- 28. Insufficient spacingof core Thinning of cores in the block, uneven cores Loss of tissue on water bath Refacing block Refacing angle