Tissue Microarray Construction, Cutting, Staining, and Analysis

Saturday 08/01/2009

The construction of tissue microarrays (TMA) from well-characterized tumors is an excellent way to efficiently evaluate tumor markers in large-scale studies. TMAs are constructed by harvesting cylindrical core biopsies from pre-existing paraffin-embedded tissue blocks and assembling hundreds of the cores into a recipient TMA block. Using this method, an entire cohort of patient/tumor samples can be analyzed for new disease biomarkers by testing a few master slides under the same experimental conditions instead of testing hundreds of conventional single slides.

FHCRC Shared Resources provide TMA services in the Specialized Pathology and Experimental Histopathology laboratories:

Since 2001 the Specialized Pathology laboratory has been providing construction, analysis, imaging and interpretation services for many diverse research projects utilizing TMA technology. The resource uses an automated tissue microarrayer to efficiently construct TMA master blocks containing up to 300 tissue cores from 80-100 patient tumors. In general, if the lab is provided with paraffin tissue blocks with corresponding marked H&E’s, two identical TMA blocks can be constructed within 48 hours. Image acquisition of assayed slides is performed using an Olympus (formerly Bacus) Bliss imaging system, which supports TMA image storage and file management using a WebSlide server that can be remotely and securely accessed using any internet capable computer. These images virtually eliminate the need for microscopic evaluation of TMA studies by providing easily accessed, diagnostic quality images that can be shared by many investigators. TMA assays can be viewed via a web interface which links the TMA images to a secure SQL server database.  The interface provides a mechanism for confidently linking TMA results with patient and clinical data.  For questions about these services or for further information please contact Liz Donato at 206-667-4501.

The Experimental Histopathology laboratory staff has extensive expertise in sectioning and preparing slides from TMAs. Our goal is to produce the greatest number of high quality sections from these valuable samples.  In addition, Experimental Histopathology has a great deal of experience performing immunohistochemistry on TMAs. These samples can pose a unique staining challenge. For instance, the tissues in the TMA may come from many different sources using different fixation and processing protocols.  As a result, the cores may exhibit variable baseline staining. The lab has developed efficient strategies to optimize antibody staining to produce more uniform staining across the TMA. Please contact Experimental Histopathology for questions about TMA sectioning and staining (call 206-667-6166 or stop by at DE-360).

Scientific Imaging now has a microscope for scanning slides called Tissuefaxs that can be used to visualize an entire TMA.  It is a Zeiss microscope with bright field and fluorescence that includes a motorized stage capable of loading and scanning 8 slides at a time. This technology is compatible with software that can be used to quantitate staining or analyze many different parameters including staining intensity or localization. Please contact Scientific Imaging for more details (206-667-4205).