Navigating Tissue Microarray Construction: A Guide for Avoiding Pitfalls and Mastering Key Technical Aspects

Abstract

Introduction: Tissue Microarray (TMA) is a novel technique that is now integral in pre-clinical and translational research. In resourcelimited settings, automated microarrayers and molds are out of reach, and manual TMA construction may be done instead. Aim: To explore the pitfalls encountered while constructing manual TMAs and to troubleshoot these problems using the available resources. Materials and Methods: A cross-sectional study was done between September 2019 and March 2021 in the Department of Pathology at a tertiary healthcare center in New Delhi using 60 mastectomy specimens. Five manual TMAs were constructed using simple, cheap, and readily available resources. Problems encountered during the construction were identified and documented. Solutions attempted to troubleshoot the common problems were documented, and their outcomes were evaluated. Results: Difficulty in core extraction, cracking of TMAs during core insertion, loss of cores, misalignment of cores, bulging of blocks, difficulty in sectioning due to non-uniform cores, and loss of cores during sectioning were major problems identified. Simple measures such as prior warming of both donor and recipient blocks, use of punch biopsy needles with a plunger, maintaining a margin around the cores, using wax cores to align cores, and adequate cooling prior to sectioning helped in overcoming these problems. Other solutions that were attempted but did not yield satisfying results included the use of agarose in paraffin blocks and the use of liquid wax to seal cracks and gaps. Conclusion: Manual TMA is not only feasible, it is easy to construct once the technique is learned and the problems that commonly arise in its construction are tackled. The modifications suggested in the present study can aid in constructing these microarrays faster and avoid both wastage of time and resources. TMAs can thus be used as an alternative to traditional paraffinbased techniques for research applications in resource-limited centers with high patient loads.