Patch TMA Construction Using Pre-Existing Slides as Source of Tissue When Paraffin Blocks Are Unavailable.
Fang-Ming Deng, Yan Zhao, Xiangtian Kong, Peng Lee, Jonathan Melamed. New York University Langone Medical Center, NY
Background: Tissue microarray (TMA) has evolved as a useful platform for tissue based studies with the advantage of miniaturization permitting entire studies on single slides. This allows standardized experimental conditions on large numbers of cases for tissue based studies. Additionally, the “same slide” platform also facilitates image analysis techniques for more standardized interpretation. Construction of tissue microarrays however has required the original paraffin block to be available to provide donor tissue. Institutions that treat referral patients receive consultation slides from many different hospitals and laboratories and are therefore often limited on studies of these materials without the original paraffin block. We describe a technique for construction of intermediate density tissue microarray slides based on transfer of tissue from pre-existing routine slides provided for pathology diagnosis in situations where the original paraffin block is unavailable.
Design: A prostate cancer TMA was constructed using 20 cores from radical prostatectomy slides. Briefly, this technique entails removal of the coverslip on each slide and reinforcement of the tissue by covering with Mount-Quick liquid mounting medium. Once the medium has hardened, the attached tissue with its new scaffold may be “biopsied” using a tissue microarray needle (1.5 mm in diameter). The resultant biopsy disk is then transferred onto a recipient slide, with adhesion of the disc to the slide accomplished using heavy pressure. The utility of this patch TMA relies on preservation of morphology and antigenicity of the tissue for immunohistochemistry and confidence that it can be performed without substantial loss of tissue. We therefore tested this in comparison to a traditional TMA by applying a patch TMA on the same slide side by side next to a traditional TMA. The slide was then subject to immunohistochemical staining with antigen retrieval and assessed for expression of the antigen and loss of tissue.
Results: After immunohistochemistry, 19 of 20 cores were intact on the traditional TMA compared with 16 of 20 cores on the patch TMA. Expression of the marker (34BE12) was similar on both the patch TMA and traditional TMA.
Conclusions: Patch TMA represents a viable alternative for tissue-based immunohistochemical studies when paraffin blocks are unavailable. This may be a valuable tool for allowing use of archival slide material and enable a standardized TMA platform to be used when the slides sent for review from other institutions are the only source of tissue available.
Monday, February 28, 2011 1:00 PM
Poster Session II # 284, Monday Afternoon