Tissue microarray construction from gross specimens: Development of a novel simple technique

Background: The tissue microarray (TMA) technique is becoming a useful tool for research and quality control methods in surgical pathology. However, the widespread use of this technique in routine surgical pathology practice, especially in developing nations, is hampered by the high cost of commercially available instruments. The authors describe a novel, inexpensive technique of construction of TMA from gross specimen. Methods: The authors used a 16-gauge bone marrow trephine biopsy needle to obtain cores from 150 specimens of breast carcinoma. These cores were processed in the tissue processor as per the routine processing techniques of the department. A recipient block was prepared, followed by drilling of a suitable number of holes. The processed tissue cores were arrayed into the recipient block. These blocks were used for immunohistochemistry and compared with conventional whole tissue sections. Results: Of the 150 cases, only two showed suboptimal preservation in the TMA block, and this was also reflected in the conventional tissue sections. Immunohistochemical staining for oestrogen receptor, progesterone receptor, Her2.neu and Ki-67 was found to be satisfactory in 148 cases with the staining intensity comparable with that performed on the conventional sections. Conclusion: This study describes a satisfactory technique for construction of TMA from a gross tumour specimen. Such a technique is well suited to centres which handle a high number of cases of a particular type, such as breast carcinoma. Further studies on other tumour types would help in validating these results.