Aim To develop and validate a technique for construction of intermediate density tissue microarray (TMA) slides based on the transfer of tissue from pre-existing routine slides provided for pathology diagnosis with validation to show preservation of morphology and antigenicity of the transferred tissue.

Methods Prostate cancer patch TMAs were constructed using 20 cores acquired from radical prostatectomy histology slides. The preservation of morphology and antigenicity of these patch TMAs were tested with immunohistochemistry (IHC) in comparison to a traditional TMA.

Results After IHC staining, 35 of 39 cores (89.7%) on the patch TMA were intact compared with 39 of 40 cores (97.5%) on the traditional TMA. Expression patterns and density of the antigens (34BE12, p63 and AMACR) on the patch TMA were almost identical to the traditional TMA.

Conclusions Patch TMA represents a viable alternative for tissue-based IHC studies when paraffin blocks are unavailable. This may be a valuable tool for allowing use of archival slide material for IHC 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.